1. 1997. PNWTIRC Annual Report 1996-97, Pacific Northwest Tree Improvement Research Cooperative. Oregon State University, Oregon, USA. ii + 29 p.

Keywords:      genetic tree improvement

                        tree/stand protection     

                        tree phenology

                        growth

                        wood quality

                        tree physiology

Abstract: The report describes highlights for 1996-97, current research (3 projects), student project updates (3 projects), planned Douglas fir [Pseudotsuga menziesii] seed orchards for the new millennium and other planned activities of the PNWTIRC, a research cooperative operating in the Pacific Northwest area of North America (USA and Canada). Details are included of publications and finances. Details of the 3 current research projects and the 3 student projects, which all concern Douglas fir, are presented as short papers including brief results: (1) Influence of second flushing on cold hardiness; (2) Seedling drought physiology study; and (3) Quantitative trait loci influencing cold hardiness; (4) Seedling cold hardiness; (5) Growth response of saplings to drought; and (6) Measurement study follow-up: age-age correlations in forking defects.

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2. Adams, T., T. Anekonda and C. Lomas. 1999. Annual Report 1998-99, Pacific Northwest Tree Improvement Research Cooperative. 33 p.

Keywords:      genetic tree improvement

                        tree/stand protection

                        tree/stand health

                        growth

                        tree physiology

Abstract: Summaries are given of research projects on improvement of Douglas fir [Pseudotsuga menziesii] in the Pacific Northwest: seedling drought physiology; genetics of dark respiration and its relationship with drought hardiness; response of saplings to drought, as measured by growth ring variables; use of microsatellite marker loci to identify pollen contamination in seed orchards; and evaluation of miniaturized seed orchard designs.

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3. Adams, W.T., S.N. Aitken, D.G. Joyce, G.T. Howe and J. Vargas-Hernandez. 2001. Evaluating efficacy of early testing for stem growth in coastal Douglas-fir. Silvae-Genetica 50(3/4): 167-175.

Keywords:      genetic tree improvement

                        nursery operations

                        growth

                        genetic relationships

Abstract: In a test to evaluate the ability to predict stem growth of families in the field from nursery performance (i.e., early testing), 67 open-pollinated families and 66 full-sib families of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were sown in two nursery conditions, each replicated as separate experiments: two bareroot nursery trials established in successive years in the same nursery, and two container-sown greenhouse trials sown in different greenhouses in the same year. First year heights in the seedling trials were compared to mean stem volumes of the same open-pollinated families in eight 15-year-old field progeny tests and the same full-sib families in eleven 12-year-old tests. Family mean nursery-field correlations (rxy) were similar for all four seedling trials for both open-pollinated (OP) and full-sib (FS) families, and generally ranged between 0.30 and 0.40. Although low, it is shown that nursery-field correlations of this magnitude can be quite useful in tree improvement programmes. For example, based on the data in this study, it is estimated that a single stage of family selection for first year seedling height would be about 50% as effective in improving 15-year volume as direct selection for this trait in field tests. Early testing, however, is probably of more practical significance as a tool for culling families prior to out-planting field tests in two-stage selection schemes. It is estimated that 25% of the OP families in this study could have been culled in an early test (first stage selection), with gain in 15-year volume after subsequent field testing and selection of the remaining families (second stage selection) being nearly the same as if all families had been field tested. Thus, early testing is an effective tool for reducing the size and cost of field progeny tests without sacrificing genetic gain.

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4.
Adams, W.T. and D.G. Joyce. 1990. Comparison of selection methods for improving volume growth in young coastal Douglas-fir. Silvae-Genetica 39(5-6): 219-226.

Keywords:      genetic tree improvement

                        growth

Abstract: Data from a Douglas fir (Pseudotsuga menziesii) open-pollinated progeny test in Oregon were used for evaluating methods of selection for bole volume. Tree height and bole diameter at breast height (DBH) were measured on 12 to 13-year-old individuals from 90 families at each of 3 plantations in the central Oregon coast range, and bole-volume estimates were derived with a quadratic volume equation. Four methods were compared for both parental and progeny selection: (1) indirect selection based on height, (2) indirect selection based on DBH, (3) direct selection based on volume, and (4) selection based on an index that included all 3 traits. Two-stage selection was also explored, where test trees are culled on the basis of DBH in the first stage; height is measured only on the remaining trees, so that final selections (the second stage) are based on volume. Estimated genetic gains in volume from progeny selection were 8-11% greater than those from parental selection. The relative efficiencies of the various selection methods, however, were similar for parental and progeny selection. The greatest estimated gains in single-stage selection, which were achieved with the multitrait index, were only 1% better than those from selections based on volume alone. Indirect selection based on DBH produced about 90% of the gain achieved by direct selection for volume, and indirect selection based on height was about 92-94% as efficient as direct selection. With 2-stage selection, up to two-thirds of the trees could be culled in stage 1 without significantly lower gains in bole volume than those expected if the height of all trees had been measured.

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5.
Alvarez, I.F. and J.M. Trappe. 1983a. Dusting roots of Abies concolor and other conifers with Pisolithus tinctorius spores at outplanting time proves ineffective. Canadian-Journal-of-Forest-Research 13(5): 1021-1023.

Keywords:      planting operations

                        site preparation

                        mechanical preparation

                        growth

                        tree/stand health

                        mycorrhizal response

Abstract: Dusting roots of Abies concolor, Abies magnifica var. shastensis, Pseudotsuga menziesii and Pinus ponderosa with Pisolithus tinctorius (Pt) spores when planted out produced no Pt mycorrhizae at the end of the first growing season. In the 3rd yr occasional Pt mycorrhizae had formed on A. concolor. Inoculations reduced seedling survival in some cases. High rates of spore application may have desiccated roots of the true firs and spore amounts applied need careful attention. Soil scarification and ripping significantly promoted growth of A. concolor seedlings compared with scarification alone.

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6.
Alvarez, I.F. and J.M. Trappe. 1983b. Effects of application rate and cold soaking pretreatment of Pisolithus spores on effectiveness as nursery inoculum on western conifers. Canadian-Journal-of-Forest-Research 13(3): 533-537.

Keywords:      nursery operations

                        growth

                        mycorrhizal response

Abstract: Ponderosa pine, Douglas fir, Shasta red (Abies magnifica var. shastensis), and white fir (Abies concolor) seedlings were inoculated in a bare root nursery with basidiospores of Pisolithus tinctorius. The spores were applied at 3 rates with or without cold/wet pretreatment of 7 or 21 days. Pretreatment did not affect spore efficiency as inoculum. Only ponderosa pine increased growth in response to inoculation. Inoculations in the greenhouse with a wider range of spore application rates revealed that a higher concn. of spores was needed to induce an increase in growth and mycorrhiza formation of Douglas fir than ponderosa pine. These levels were much higher than those used in nursery inoculations.

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7.
Amaranthus, M.P. and D.A. Perry. 1987. Effect of soil transfer on ectomycorrhiza formation and the survival and growth of conifer seedlings on old, nonreforested clear-cuts. Canadian-Journal-of-Forest-Research 17(8): 944-950.

Keywords:      planting operations

                        tree/stand health

                        growth

                        mycorrhizal response

Abstract: Small amounts (150 ml) of soil from established conifer plantations and mature forest were transferred to planting holes on 3 sites in the Klamath Mts., S. Oregon and N. California. The sites had been clear felled and burned 8-27 yr earlier and unsuccessfully reforested. At Cedar Camp, a high alt. (1720 m) southerly slope with sandy soil, transfer of soil from a Douglas fir plantation increased first-yr survival of Douglas fir seedlings by 50%, mycorrhizal formation and b.a. growth. Soil from mature forest did not enhance survival and growth. Soil transfer was less effective on 2 sites at lower alt. with clayey soils. Douglas fir seedlings at Crazy Peak showed similar, but less well defined, patterns to those at Cedar Camp. All Pinus lambertiana seedlings at Wood Creek survived well and were generally unaffected by soil transfer. Results suggest that adequate mycorrhizal formation is critical to seedling growth and survival on cold, droughty sites. Transfer of soil from a suitable source may offset the decline in native mycorrhizal fungi if reforestation is delayed.

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8.
Amaranthus, M.P. and D.A. Perry. 1989a. Interaction effects of vegetation type and Pacific madrone soil inocula on survival, growth and mycorrhiza formation of Douglas-fir. Canadian-Journal-of-Forest-Research 19(5): 550-556.

Keywords:      planting operations

                        growth

                        tree/stand health

                        mycorrhizal response

Abstract: One-yr-old non-mycorrhizal Douglas fir (Pseudotsuga menziesii) seedlings were planted in 1985 in cleared blocks within 3 adjacent vegetation types in SW Oregon, viz., whiteleaf manzanita (Arctostaphylos viscida), annual grass meadow, and an open stand of Oregon white oak (Quercus garryana). Within subplots in each block, either pasteurized or unpasteurized soil from a nearby Pacific madrone (Arbutus menziesii) stand was transferred to the planting holes of the seedlings; control seedlings received no madrone soil. Second-year survival averaged 92, 43 and 12% for seedlings planted on the manzanita, meadow and oak sites, respectively. Growth differences generally paralleled survival differences. Added madrone soil, whether pasteurized or unpasteurized, did not influence survival. Unpasteurized madrone soil substantially increased the growth of seedlings on the manzanita site, but not in the meadow or oak stand. Pasteurized madrone soil did not affect growth in any of the vegetation types. Unpasteurized madrone soil nearly tripled the number of mycorrhizal root tips forming on seedlings and resulted in formation of a new mycorrhiza type on the manzanita site, although it had little or no effect on the meadow or oak sites. These results suggest that manzanita and madrone impose a biological pattern on soils that stimulates Douglas fir growth and survival, and support results of other studies indicating that root symbionts and rhizosphere organisms mediate interactions among plant species.

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9.
Anekonda, T.S., M.C. Lomas, W.T. Adams, K.L. Kavanagh and S.N. Aitken. 2002. Genetic variation in drought hardiness of coastal Douglas-fir seedlings from British Columbia. Canadian-Journal-of-Forest-Research 32(10): 1701-1716.

Keywords:      genetic tree improvement

                        tree/stand protection

                        growth

                        tree/stand health

                        genetic relationships

                        tree physiology

Abstract: Genetic variation in drought hardiness traits and their genetic correlations with growth potential and recovery traits were investigated in 39 full-sib families of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) from southwestern British Columbia, Canada. Seedlings of these families were grown in raised nursery beds and subjected to three moisture regimes each in the second (well-watered or control, mild, and moderate drought) and third (control, severe drought, and recovery from second-year moderate drought) seasons. Traits assessed included drought hardiness (foliage damage, cavitation of xylem tracheids, xylem hydraulic conductivity, and height and diameter growth increment) in the drought treatments, growth potential (total height and diameter) in the control treatment, and height and diameter growth increments in the recovery treatment. Xylem cavitation in the growth ring produced in a particular year was nearly three times greater under the moderate drought and four times greater under the severe drought than in the control treatment. Xylem hydraulic conductivity of seedlings in the severe drought treatment was 40% lower than conductivity of seedlings under the control treatment. Mean foliage damage in seedlings subjected to severe drought (third season) was much greater (33%) than in seedlings subjected to mild or moderate drought (second season). Families differed significantly in most drought hardiness traits, with individual tree heritabilities averaging 0.19. Thus, much potential exists for identifying drought-hardy families at the seedling stage and using this information for deployment or breeding purposes. In addition, most hardiness traits were strongly intercorrelated (genetic correlations often exceeded |0.80|) indicating that these traits are controlled largely by the same set of genes and that selection for hardiness based on one trait will increase hardiness as reflected in the other traits as well. Genetic correlations were only moderate (0.49) between hardiness traits measured in different years, perhaps due to the large difference in severity of the drought applied in the two seasons. Although injury to seedlings, as reflected in foliage damage and xylem cavitation, was relatively low under the moderate drought of the second season, it did result in reduced growth increment the following (recovery) year. Growth potential under favourable moisture regimes was nearly uncorrelated with drought hardiness, suggesting that drought hardiness could be improved in this southwestern British Columbia breeding population without negatively impacting growth potential in favourable moisture conditions.

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10.
Arnott, J.T. and D. Beddows. 1982. Influence of Styroblock container size on field performance of Douglas-fir, western hemlock, and Sitka spruce. Tree Planters' Notes 33(3): 31-34.

Keywords:      nursery operations

                        growth

                        tree/stand health

Abstract: Pseudotsuga menziesii, Tsuga heterophylla and Picea sitchensis seeds were sown in April 1971 in BC/CFS Styroblocks sizes 2 and 8 with volumes of 40 and 125 cmsuperscript 3 respectively. The seedlings in the larger containers were kept in a heated greenhouse for 2-3 months to stimulate growth to fill the containers, before joining those in the smaller containers in an outdoor shadehouse nursery. Seedlings were planted out in British Columbia in March 1972. A second trial was started in April 1972 and seedlings planted out in April 1973. Survival and ht. growth were recorded for 5 growing seasons. The larger containers produced larger seedlings at planting. There were n.s.d. in survival of seedlings grown in the different sized containers for all 3 species. The seedlings grown in the larger containers were significantly taller after the first growing season in the field, a difference which persisted for the 5 seasons. Growing seedlings in the larger containers was more expensive and the seedlings took longer to plant than those grown in the smaller containers.

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11.
Arnott, J.T. and F.T. Pendl. 1994. Field performance of several tree species and stock types planted in montane forests of coastal British Columbia. Canadian-Forest-Service, Pacific and Yukon Region Information Report BC-X-347. viii + 45 p.

Keywords:      nursery operations

                        planting operations

                        growth

                        tree/stand health

                        wood quality

Abstract: Planting trials were established at sites within the Mountain Hemlock and montane Coastal Western Hemlock biogeoclimatic zones. Six test areas were chosen within each zone. Amabilis fir (Abies amabilis), noble fir (A. procera), yellow cedar (Chamaecyparis nootkatensis) and mountain hemlock (Tsuga mertensiana) were the species selected for planting in the Mountain Hemlock zone. In addition to Abies amabilis and A. procera, western white pine (Pinus monticola), western redcedar (Thuja plicata), Douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) were planted in the Coastal Western Hemlock zone. Plug (PSB 211), plug transplant and bareroot stock types were used for the eight species across both zones. Seedlings were planted during the autumn (September/October) and spring (May) in each of two successive years: 1978-79 and 1979-80. Survival, growth and tree form 13 years after planting were used as indicators of the reliability (a combination of tree survival and form) and productivity of the planting treatment combinations. Noble fir and amabilis fir were the most reliable species in the Mountain Hemlock zone; i.e. these species have average survival rates higher than 80% and few form defects. Yellow cedar crowns were badly broken by snow, which reduced the reliability of this species in the early years of plantation establishment. The growth, survival and form of mountain hemlock ranked between that of the true firs and yellow cedar. Noble fir was by far the most productive species in the Mountain Hemlock zone. Within the Coastal Western Hemlock zone no single species demonstrated a superior combination of productivity or reliability. Douglas fir, western hemlock and western redcedar were good species in the lower elevations of the zone, whereas noble fir and amabilis fir were better species at the upper elevational limits of the zone. Western white pines should be avoided until rust-resistant seed sources are available. Little variation was found among the three planting stock options and even less between the two planting seasons. Plug transplant stock was more reliable than bareroot or plug stock; productivity ranked from greatest to least in the following order within both zones: plug transplant, bareroot and plug stock. This ranking among stock types may well change as different stock types are developed. However, the relative size and design differences among stock types, no matter when they become available, will always have an effect on the ultimate reliability and productivity of planted trees. Autumn planting gave significantly lower survival in the Coastal Western Hemlock zone only.

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12.
Axelrood, P.E., M. Neumann, D. Trotter, R. Radley, G. Shrimpton and J. Dennis. 1995. Seedborne Fusarium on Douglas-fir: pathogenicity and seed stratification method to decrease Fusarium contamination. New-Forests 9(1): 35-51.

Keywords:      nursery operations

                        tree/stand protection

                        tree/stand health

                        growth

Abstract: Twelve Douglas-fir (Pseudotsuga menziesii) seedlots from coastal British Columbia were assayed for seedborne Fusarium; all of the seedlots were contaminated. The percentage of non-stratified seeds from individual seedlots harbouring Fusarium ranged from 0.3 to 95.4. Sixty-seven percent of the seedlots had Fusarium on less than 2% of the seeds. Post-stratification seedborne Fusarium levels were significantly less for running water imbibition compared with standing water imbibition. However, seedling growth at a container nursery was not consistently different for stratified seed imbibed initially in standing or running water. Fusarium disease symptoms were not observed in the nursery environment. The species of Fusarium isolated from seed were F. acuminatum [Gibberella acuminata], F. avenaceum [G. avenacea], F. lateritium [G. baccata], F. moniliforme [G. fujikuroi], F. oxysporum, F. poae and F. sambucinum [G. pulicaris]. Twelve Fusarium isolates, comprising 6 species, were assessed for pathogenicity. Disease symptoms were observed after 4 weeks incubation and Fusarium isolates ranged in virulence from low to high. Fusarium oxysporum isolates were the most pathogenic.

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13.
Ballard, T.M. 1984. A simple model for predicting stand volume growth response to fertilizer application. Canadian-Journal-of-Forest-Research 14(5): 661-665.

Keywords:      fertilization

                        growth

Abstract: The equation R=KTACZQ is used to predict cumulative stand volume growth response (R) to fertilizer application, where K is a constant and the last 5 (dimensionless) multipliers represent functions of time, amount of fertilizer applied, stand composition, stocking, and site quality, respectively. Site-specific input data requirements are stand composition expressed as percent responding species, stocking expressed as a percentage of normal stocking, and site index. The model was calibrated for Douglas-fir response to nitrogen using data from Washington and Oregon. A preliminary test of the model and its calibration compared predicted responses with estimates of actual response derived from some fertilizer trials on Vancouver Island. Soil drainage class and foliar analysis data may help in qualitatively inferring whether the model's site quality function leads to overestimation of response. Future development of the model may include development and calibration of a predictively better site quality function which quantitatively uses site water regime and stand nutrient data.

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14.
Ballard, T.M. and N. Majid. 1985. Use of pretreatment increment data in evaluating tree growth response to fertilization. Canadian-Journal-of-Forest-Research 15(1): 18-22.

Keywords:      fertilization

                        growth

Abstract: The use of pretreatment increment can lead to improved estimates of individual and average tree growth response to fertilizing, by helping to adjust for site as well as stand structure differences between fertilized and control areas. It has applications in research using either single-tree or plot fertilizing, and also in estimating responses to operational fertilizing. Equations for analysing increment response to fertilizing are presented and discussed and 2 particularly useful ones were evaluated by examining branch length increment data from foliar spray application of iron and copper to Pinus contorta and of nitrogen and iron to Pseudotsuga menziesii, in field trials in British Columbia.

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15.
Barclay, H., H. Brix and C.R. Layton. 1982. Fertilization and thinning effects on a Douglas-fir ecosystem at Shawnigan Lake: 9 year growth response. Pacific-Forestry-Centre, Canadian-Forest-Service Information-Report BC-X-238. 35 p.

Keywords:      fertilization

                        thinning

                        growth

Abstract: Further results are given for a trial established in 1970 in a 24-yr-old stand in British Columbia, last measured 6 yr after treatment. Volume increments over 9 yr for heavy thinning alone, heavy fertilizer (urea) treatment alone, or both together, were 46%, 75% and 120%, respectively.

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16.
Barclay, H.J. and H. Brix. 1984. Effects of urea and ammonium nitrate fertilizer on growth of a young thinned and unthinned Douglas-fir stand. Canadian-Journal-of-Forest-Research 14(6): 952-955.

Keywords:      fertilization

                        thinning

                        growth

                        tree physiology

                        tree/stand health

Abstract: The effects were studied of 2 sources of nitrogen fertilizer applied at rates of 224 and 448 kg/ha N on growth of thinned and unthinned plots established in 1970 in a 24-yr-old stand on southern Vancouver Is., British Columbia. Ammonium nitrate yielded higher growth of diam. and vol. than urea over a 9-yr period, particularly with thinning. Ht. growth was not affected by nitrogen source. The efficiency of nitrogen fertilizing in terms of stem vol. response per kilogram of nitrogen applied was greatest with ammonium nitrate in thinned plots. Tree mortality increased substantially with fertilizing for both sources, and decreased markedly with thinning.

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17.
Barclay, H.J. and H. Brix. 1985a. Effects of high levels of fertilization with urea on growth of thinned and unthinned Douglas-fir stands. Canadian-Journal-of-Forest-Research 15(4): 730-733.

Keywords:      fertilization

                        thinning

                        growth

                        tree physiology

                        tree/stand health

Abstract: Diameter height and volume growth were documented for 9 yr after thinning and fertilizing in a 24-yr-old stand on a poor site on southern Vancouver Is. The treatments involved 3 thinning treatments (0, 1/3, and 2/3 b.a. removed) and 6 fertilizer treatments (0-1344 kg/ha N) with urea. Increments for both diameter and gross volume increased with the rate of fertilizer application and responses were still apparent 9 yr after treatment. For unthinned plots, the 9-yr volume growth responses were 30, 50, and 80% with fertilizer rates of 224, 448, and 896 kg/ha N, respectively. The efficiency of fertilizer use, measured as stem volume response per unit of nitrogen applied, decreased with rate of fertilizer application, but this result may change over a longer response period. There was a positive interaction between fertilizing and thinning such that high amounts of both mutually enhanced growth. Mortality increased with fertilizing, but only noticeably in unthinned plots.

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18.
Barclay, H.J. and H. Brix. 1985b. Fertilization and thinning effects on a Douglas-fir ecosystem at Shawnigan Lake: 12-year growth response. Pacific-Forestry-Centre, Canadian-Forest-Service Information-Report BC-X-271. 34 p.

Keywords:      fertilization

                        thinning

                        growth

Abstract: [See FA 45, 2316] Further results are given from the study established in 1970 in a 24-yr-old stand in British Columbia. Fertilizers (urea) and thinning both increased vol. increments over 12 yr. Refertilization 9 yr after initial treatment has produced substantial increases in vol. increment.

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19.
Barclay, H.J. and Y.A. El-Kassaby. 1988. Selection for cone production in Douglas-fir adversely affects growth. In Proceedings: 10th North American Forest Biology Workshop: 'Physiology and genetics of reforestation', University of British Columbia, Vancouver, British Columbia, July 10-22, 1988. Eds. J. Worrall, J. Loo-Dinkins and D.P. Lester. pp. 149-151.

Keywords:      genetic tree improvement

                        genetic relationships

                        growth

                        reproduction

Abstract: Cone production and radial growth increment were studied for 8 years in a Douglas fir (Pseudotsuga menziesii) seed orchard on Vancouver Island, British Columbia, in 365 trees representing 29 open-pollinated (half-sib) families. Genetic correlations for the two traits were compared for each of the 8 years. Six of the correlations were significantly negative, while the remaining two were significantly positive. The predominantly negative correlation between cone production and growth indicates that selection for one of these two characters will effectively select against the other. The practice of selecting for high cone-producing trees in seed orchards may also be expected to yield slower-growing trees.

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20.
Barclay, H.J. and C.R. Layton. 1990. Growth and mortality in managed Douglas fir: relation to a competition index. Forest-Ecology-and-Management 36(2-4): 187-204.

Keywords:      fertilization

                        thinning

                        growth

                        tree/stand health

Abstract: Twelve-year increments of diameter at breast height (DBH), height, and volume in thinned and fertilized 45-year-old Douglas fir (Pseudotsuga menziesii) stands on Vancouver Island, Canada, were related (by regression) to degree of thinning, amount of fertilizer (3x3 factorial), initial DBH, and a competitive stress index (CSI). The ability of the CSI to predict growth after treatment was examined. Causes of tree death, and CSI data, are presented, and the relationship between them discussed. The CSI was found to be only moderately good at predicting Douglas fir growth and mortality: initial DBH provided a better predictor. Most mortality in unthinned plots resulted from suppression, and correlated reasonably well with CSI; mortality in thinned plots was not correlated with CSI, and resulted principally from snow damage. Tree height variability generally became less over the 12 years following treatment, which is more consistent with two-sided than one-sided competition predictions, a result which is contrasted to that of many other species.

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21.
Beddows, D. 2002. Levels-of-growing-stock cooperative study in Douglas-fir: Report No. 16 - Sayward Forest and Shawnigan Lake. Pacific-Forestry-Centre, Canadian-Forest-Service Information-Report BC-X-393. viii + 67 p.

Keywords:      thinning

                        growth

                        tree morphology

Abstract: Results from the two levels-of-growing-stock installations at Sayward Forest and Shawnigan Lake on Vancouver Island, British Columbia, Canada, are summarized. Volume growth at both the site-III Sayward Forest installation to age 51 and the site-IV Shawnigan Lake installation to age 52 has been strongly related to level of growing stock. Basal area growth followed a similar, though weaker, trend. Thinning has affected stand development through tree size distribution and live crown development. Periodic annual increments in volume at both installations are still two to three times the mean annual increment, indicating the potential for productivity gains as the treated stands age. Results to date from both installations are similar to results from other cooperative installations, generally differing from the more productive sites only in the rate and degree of response associated with a lower site quality.

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22
. Berch, S.M. and A.L. Roth. 1993. Ectomycorrhizae and growth of Douglas-fir seedlings preinoculated with Rhizopogon vinicolor and outplanted on eastern Vancouver Island. Canadian-Journal-of-Forest-Research 23(8): 1711-1715.

Keywords:      nursery operations

                        mycorrhizal response

                        growth

Abstract: Ectomycorrhizal colonization of container-grown Douglas fir (Pseudotsuga menziesii) inoculated with Rhizopogon vinicolor was determined after cold storage and one growing season after outplanting (in March 1988) on a clear felled area on eastern Vancouver Island, British Columbia. Inoculated Douglas fir seedlings were taller than noninoculated controls when outplanted, but perhaps because of browse damage, no growth differences were found after one growing season in the field. R. vinicolor colonized all of the inoculated but none of the control seedlings examined after cold storage. Volunteer Thelephora terrestris colonized almost half of the control and 10% of the inoculated seedlings before outplanting. After one field season, inoculated and control seedlings were colonized by 15 ectomycorrhizal fungi each, only eight of which were found on both. R. vinicolor persisted on the roots of inoculated plants, but was also present in the field soil since the control seedlings also bore these mycorrhizas after one growing season. The relative abundance of T. terrestris decreased from the nursery to the field. The other common ectomycorrhizas in the field included Mycelium radicis atrovirens, Cenococcum geophilum and types resembling Tuber and Endogone.

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23.
Binkley, D. 1984. Importance of size-density relationships in mixed stands of Douglas-fir and red alder. Forest-Ecology-and-Management 9(2): 81-85.

Keywords:      thinning

                        growth

                        tree/stand health

Abstract: Pairs of Douglas-fir, and Douglas-fir and red alder (Alnus rubra) stands were examined at four locations (in Oregon, Washington and British Columbia) for patterns in average tree size as a function of stand density. On fertile sites, the mixed stands experienced higher mortality than the pure conifer stands. On infertile sites, the pure conifer stands were well below the maximum tree size and density relationship compared to fertile sites or mixed stands, suggesting under-utilized site resources were available for nitrogen-fixing alder.

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24.
Binkley, D. and P. Reid. 1984. Long-term responses of stem growth and leaf area to thinning and fertilization in a Douglas-fir plantation. Canadian-Journal-of-Forest-Research 14(5): 656-660.

Keywords:      fertilization

                        thinning

                        tree morphology

                        carbon allocation

                        growth

Abstract: Replicated thinning and nitrogen fertilization plots in a 53-year-old plantation in Washington State were examined for repsonses in stem growth, leaf area, and stem growth per unit leaf area. Although measurements occurred 20-30 yr after plot installation, substantial effects from the various treatments were still present. Thinning reduced leaf area of the stands but increased stem growth per unit leaf area, resulting in little difference in stem growth per ha over the 5-yr measurement period (1977-81). Fertilization increased both stand leaf area and stem growth per unit leaf area, and more than doubled 5-yr stem growth per ha. Consideration of the role of leaf area and stem growth per unit leaf area in determining stand treatment responses may account for much of the variation found among replicates of treatments or between studies on different sites.

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25.
Binkley, D. and P. Reid. 1985. Long-term increase of nitrogen availability from fertilization of Douglas-fir. Canadian-Journal-of-Forest-Research 15(4): 723-724.

Keywords:      fertilization

                        growth

                        tree physiology

                        soil properties

Abstract: [See FA 44, 4708; 46, 1837] Most Douglas-fir stands respond to nitrogen fertilizing by increasing stem growth for less than 8 yr, but one plantation at the United States Forest Service Wind River Experimental Forest in Washington State has responded for over 15 yr. In this study nitrogen concn. of foliage and fresh litter were shown to be higher in the fertilized plots (470 kg/ha N) 18 yr after fertilizing. Retranslocation of N from senescent needles was not affected and stem growth per unit N in the canopy was similar between unfertilized and fertilized plots. An index of soil N availability in the fertilized plots was twice that of unfertilized plots. The higher stem growth, leaf area, and stem growth per unit leaf area demonstrated in an earlier study appeared to be related to a sustained increase in soil N availability rather than increased N-use efficiency. An examination of soil N transformation processes is needed to complete the explanation of the unusually prolonged fertilizer response in these plots.

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26.
Birchler, T.M., R. Rose and D.L. Haase. 2001. Fall fertilization with N and K: effects on Douglas-fir seedling quality and performance. Western-Journal-of-Applied-Forestry 16(2): 71-79.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

                        tree morphology

                        tree/stand health

Abstract: Coastal Douglas fir (Pseudotsuga menziesii) 1+1 seedlings from coastal Oregon, USA, were applied with two fertilizers (NH4NO3+K2SO4 and (NH4)2SO4+KCl) at four rates (0, 80, 160, 320 kg N and K/ha) split over three application dates (September 19, October 13, November 1, 1996). Fertilizer type did not affect total Kjeldahl nitrogen (TKN) levels on any of the sampling dates. By January 10, TKN concentrations had increased 16, 30 and 34%, and chloride concentrations had increased 57, 77 and 112% relative to the seedlings without fertilizer, for 80, 160 and 320 kg N+K/ha treatments, respectively. Nitrate levels increased briefly after the first application of NH4NO3+K2SO4. Potassium levels remained relatively unchanged. Levels of most other nutrients, as well as foliar dry weight, increased between September 16 and January 10, but these increases were generally unrelated to the fertilizer treatments. Root growth potential and cold hardiness did not differ among treatments. Seedlings that received 160 or 320 kg N/ha broke bud an average of 3 days earlier than the seedlings without fertilizer. Chlorophyll fluorescence (Fv/Fm) of seedlings with fertilizer was consistently higher than that of seedlings without fertilizer on November 13 and December 30. These treatment differences were not reflected in seedling outplanting performance after one growing season.

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27.
Birot, Y. and C. Christophe. 1983. Genetic structures and expected genetic gains from multitrait selection in wild populations of Douglas fir and Sitka spruce. I. Genetic variation between and within populations. Silvae-Genetica 32(5/6): 141-151.

Keywords:      genetic tree improvement

                        genetic relationships

                        growth

                        tree phenology

                        tree morphology

Abstract: For Douglas fir, 371 open-pollinated progenies from 26 provenances ranging from N. to S. along the western foothills of the Cascade Mts., Washington, were tested. For Sitka spruce, 292 open-pollinated progenies from 21 provenances ranging from S. British Columbia to middle-Oregon were tested. Observations were made on growth, phenology and form from the nursery stage up to age 12. Classical patterns of geographic variation were observed for both species. Heritability and genetic correlations varied from one provenance to another, especially for Douglas fir, and also changed over time. Sitka spruce showed high additive effects, offering good prospects of future genetic gains. It was concluded that preliminary investigations on genetic parameters were necessary before setting up a breeding strategy.

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28.
Black, C.H. 1988. Interaction of phosphorus fertilizer form and soil medium on Douglas-fir seedling phosphorus content, growth and photosynthesis. Plant-and-Soil 106(2): 191-199.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

                        photosynthesis

Abstract: Douglas-fir seedlings were grown in containers in peat-vermiculite or mineral soil each amended with different levels of concentrated superphosphate (CSP) or a granulated North Carolina phosphate rock (RP). Dilute acid-fluoride extractable phosphorus (DAP), seedling photosynthesis, weights, and tissue P concentrations were measured at 65 + 3 and 105 + 3 days.DAP was highly correlated with soluble fertilizer P (but not total P) added at the beginning of the experiment. Considerable soluble P was lost from peat-vermiculite but not from the mineral soil. Seedling total P content was proportional to the amount of soluble P per container at both harvests, but was greater for a given level of soluble P in the organic versus the mineral medium. Added soluble P increased foliar P concentrations, plant P content, and dry weight. Net carbon uptake was highly correlated with added levels of soluble P, foliar P concentrations, and with total P content. The internal efficiency of P from the RP source was less than P from CSP with respect to P content versus growth, net CO2 uptake, and net photosynthesis rates. At the end of the experiment, seedling P content plus DAP remaining in the media for the higher fertilizer rates accounted for 75% of the originally added soluble P in the mineral soils, but for only 15% in the organic media.

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29.
Blake, J., S.R. Webster and S.P. Gessel. 1988a. Soil sulfate-sulfur and growth responses of nitrogen-fertilized Douglas-fir to sulfur. Soil-Science-Society-of-America-Journal 52(4): 1141-1147.

Keywords:      fertilization

                        soil properties

                        growth

Abstract: Two studies were conducted to determine the growth response of N-fertilized Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] to S supplements. The relationship between response and soil SO4-S extracted with Morgan's solution, 1.22 M NaOAc + 0.53 M HOAc (pH 4.8), was used to establish critical levels for S. Douglas fir seedlings were grown in the greenhouse in the surface mineral layer (0 to 0.15 m) of 20 forest soils from western Washington and Oregon. On the average, significant increases in total dry weight (17.5%), stem diameter (10.1%), and height (6.9%) occurred when soils were fertilized with N and S in comparison to N alone. Using the Cate-Nelson procedure, growth responses to N and S were most likely to occur when soil SO4-S was below 14 mg S kg-1. Twenty eight installations were established in the field containing five treatments, three rates of N as urea, and one plot of 336 kg N ha-1 with P, K, Ca, and S. Differences in percent basal area growth between N alone and N with P, K, Ca, and S were significantly related to soil SO4-S. Over the initial 5-yr period, response over N alone was improved by 74% when soil SO4-S was <20 mg S kg-1. When the N with P, K, Ca, and S plots were retreated with only N and S, response over the next 3 yr was more than doubled compared with N alone. Identification of S responsive stands was improved by the inclusion of stand age weighted subsoil SO4-S concentrations.

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30.
Blake, J.I., H.N. Chappell, W.S. Bennett, S.R. Webster and S.P. Gessel. 1990. Douglas fir growth and foliar nutrient responses to nitrogen and sulfur fertilization. Soil-Science-Society-of-America-Journal 54(1): 257-262.

Keywords:      fertilization

                        tree physiology

                        growth

Abstract: Nitrogen-fertilizer response in conifer stands of the Pacific Northwest has been related to soil and foliar S, and growth has sometimes been enhanced by the addition of S. Five stands of Douglas fir (Pseudotsuga menziesii) in Washington or Oregon, with low to moderate quantities of sulfate in the mineral soil horizon, were treated with N (urea) alone or with S (as ammonium sulfate). The results indicated that levels of soil sulfate did not provide local or site-specific predictions of the magnitude of the gain from applying N with S. The observed treatment effects were highly variable. Foliar N concentrations in the N plus S treatment were generally higher than in the N treatment. Little change in foliar S content occurred in the N plus S plot. Periodic annual growth response to N over the study period was inversely related to site index and directly related to foliar N content.

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31.
Bledsoe, C.S. and R.J. Zasoski. 1983. Effects of ammonium and nitrate on growth and nitrogen uptake by mycorrhizal Douglas-fir seedlings. In Tree root systems and their mycorrhizas. Ed. D. Atkinson. pp. 445-454.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

                        tree morphology

                        tree/stand health

Abstract: In a greenhouse pot study, 1-yr-old mycorrhizal (inoculated with Hebeloma crustuliniforme) and non-mycorrhizal Douglas fir seedlings were grown in sandy forest soil amended with 10% of clay minerals (bentonite and/or kaolinite) and ammonium or nitrate fertilizer. Ht. growth, root and shoot DM and accumulation of nitrogen and P were greater in mycorrhizal than non-mycorrhizal seedlings, especially in the nitrate treatment. Ammonium interacted with kaolinite to reduce survival which again was poorer in the absence of mycorrhiza.

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32.
Brand, D.G. 1986a. A competition index for predicting the vigour of planted Douglas-fir in southwestern British Columbia. Canadian-Journal-of-Forest-Research 16(1): 23-29.

Keywords:      planting operations

                        tree/stand health

                        growth

Abstract: As a method of quantifying brush competition, data from 124 planted Douglas firs, age 1-5 yr, were used to derive a competition index to predict changes in tree vigour measured as a relative production rate. The index, which includes measures of brush proximity, relative ht. and % ground cover, appears to act as a measure of light interception around the tree crown. Tree vigour was found to be largely a function of the age of the tree from planting and the competition index. Foliage-based measures of growth vigour were related more strongly to the index than measures of b.a. or ht. The index has potential for assessing interspecific competition problems on suitable sites. Caution must be used in extrapolating results outside Douglas fir plantations on moist rich sites in coastal BC.

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33.
Brand, D.G. 1986b. Competition-induced changes in developmental features of planted Douglas-fir in southwestern British Columbia. Canadian-Journal-of-Forest-Research 16(2): 191-196.

Keywords:      planting operations

                        tree morphology

                        tree physiology

                        growth

Abstract: From measurements in 1- to 5-yr-old plantations, developmental characteristics of Douglas fir were tested against a competition index based on measures of the brush canopy surrounding individual trees. The most promising characteristics for assessing competition were specific leaf area, the allometric relationship of ht. to b.a. and bud production on nodal shoots. Measures of foliar N and leaf internode length were less well correlated with the competition index. Comparing these results with those of laboratory studies indicated that, on the study sites, brush competition effects on planted trees are expressed through adaptation to reduced light intensity. Developmental variables relating to moisture and nutritional status were not as strongly related to the competition index. This may reflect reduced tree demand or secondary brush canopy effects.

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34.
Brandeis, T.J., M. Newton and E.C. Cole. 2001. Underplanted conifer seedling survival and growth in thinned Douglas-fir stands. Canadian-Journal-of-Forest-Research 31(2): 302-312.

Keywords:      planting operations

                        thinning

                        commercial thinning

                        site preparation

                        chemical preparation

                        release treatments

                        chemical release

                        growth

                        tree/stand health

                        regeneration

Abstract: In a multilevel study conducted at the Oregon State University's McDonald-Dunn Research Forest, Oregon, USA, to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), western redcedar (Thuja plicata) and western hemlock (Tsuga heterophylla) seedlings were planted in January 1993 beneath second-growth Douglas-fir stands that had been thinned in 1992 to basal areas ranging from 16 to 31 m2/ha. Understorey vegetation was treated with a broadcast herbicide (glyphosate + imazapyr) application prior to thinning, a directed release herbicide (glyphosate, plus triclopyr for tolerant woody stems) application 2 years later, or no treatment beyond harvest disturbance. Residual overstorey density was negatively correlated with percent survival for all four species. Broadcast herbicide application improved survival of grand fir and western hemlock. Western redcedar, grand fir and western hemlock stem volumes were inversely related to overstorey tree density and this effect increased over time. There was a strong indication that this was also the case for Douglas-fir. Reduction of competing understorey vegetation resulted in larger fourth-year stem volumes in grand fir and western hemlock.

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35.
Brandeis, T.J., M. Newton and E.C. Cole. 2002. Biotic injuries on conifer seedlings planted in forest understory environments. New Forests 24:1-14.

Keywords:      planting operations

                        site preparation

                        chemical preparation

                        release treatments

                        chemical release

                        thinning

                        tree/stand protection

                        growth

                        tree/stand health

Abstract: The effects of partial overstorey retention, understorey vegetation management, and protective Vexar(R) tubing on the frequency and severity of biotic injuries in a two-storied stand underplanted with western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), and western hemlock (Tsuga heterophylla) were investigated. The most prevalent source of damage was browsing by black-tailed deer (Odocoileus hemionis columbiana); deer browsed over 74% of Douglas-fir and over 36% of western redcedar seedlings one or more times over the four years of this study. Neither the spatial pattern of thinning (even or uneven) nor the density of residual overstorey affected browsing frequency. Spraying subplots may have slightly increased browsing frequency, but the resulting reduction of the adjacent understorey vegetation increased the volume of all seedlings by 13%, whether or not they were browsed. Vexar(R) tubing did not substantially affect seedling survival, browsing damage frequency, or fourth-year volume. Greater levels of overstorey retention reduced frequency of second flushing. Chafing by deer and girdling by rodents and other small mammals began once seedlings surpassed 1 m in height. Essentially all grand fir seedlings exhibited a foliar fungus infection.

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36.
Brix, H. 1984. Effects of thinning and nitrogen fertilization on growth of Douglas-fir: relative contribution of foliage quantity and efficiency. Canadian-Journal-of-Forest-Research 13(1): 167-175.

Keywords:      fertilization

                        thinning

                        growth

                        carbon allocation

                        tree morphology

Abstract: [See FA 43, 1948, 3839] On Vancouver Island, aboveground biomass and annual production over 7 yr was studied in relation to thinning and nitrogen fertilization at 24 yr old. Biomass yield of both treatments increased during the first 3-4 yr then decreased for fertilization but not with thinning. Treatments doubled biomass production of individual trees over the study period when applied separately and quadrupled it when combined. Annual biomass production per unit of foliage (E) increased during the first 3-4 yr, but was at or below control level after 7 yr. E accounted for 20, 37, and 27% of the stemwood dry matter response to thinning, fertilization and the combined treatments, respectively; the remainder was attributed to an increase in foliage biomass. Thinning, but not fertilization, influenced distribution of radial growth along the stem, increasing growth only below the top one-third of the stem. This pattern was related to crown development.

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37.
Brix, H. 1993. Fertilization and thinning effect on a Douglas-fir ecosystem at Shawnigan Lake: a synthesis of project results. B.C. Ministry of Forests FRDA-Report 196. X + 64 p.

Keywords:      fertilization

                        thinning

                        growth

                        tree morphology

                        tree/stand health

                        carbon allocation

                        wood quality

                        tree physiology

                        photosynthesis

                        economics

Abstract: Treatments were initiated in 1970-71 in a 24-year-old Douglas fir (Pseudotsuga menziesii) near Shawnigan Lake, Vancouver Island, British Columbia, to determine the effects of 3 intensities of thinning (removing none, one-third and two-thirds of basal area) and 3 levels of urea fertilizer (0, 224 and 448 kg N/ha) on the growth and biology of the trees. Subsidiary experiments were established during 1972-87 to examine the effects of high doses of urea (672-1344 kg N/ha), ammonium nitrate as an N source instead of urea, understorey response to thinning and fertilizer, and responses to P and S fertilizer.

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38.
Busse, M.D., G.O. Fiddler and A.W. Ratcliff. 2004. Ectomycorrhizal formation in herbicide-treated soils of differing clay and organic matter content. Water, Air, and Soil Pollution 152:23-34.

Keywords:      release treatments

                        chemical release

                        growth

                        tree morphology

                        tree/stand health

                        soil properties

                        mycorrhizal response

Abstract: Herbicides are commonly used on private timberlands in the western United States for site preparation and control of competing vegetation. How non-target soil biota respond to herbicide applications, however, is not thoroughly understood. We tested the effects of triclorpyr, imazapyr, and sulfometuron methyl on ectomycorrhizal formation in a greenhouse study. Ponderosa pine, Douglas-fir, and white fir seedlings were grown in four forest soils ranging in clay content from 9 to 33% and organic matter content from 3 to 17%, and treated with commercial formulations of each herbicide at 0, 1.0, and 2.0 times the recommended field rate. Many of the possible herbicide-soil combinations resulted in reduced seedling growth. Root development was particularly sensitive to the three herbicides, with an average of 51% fewer root tips compared to the control treatment. The ability of mycorrhizal fungi to infect the remaining root tips, however, was uninhibited. Mycorrhizal formation was high, averaging 91% of all root tips, regardless of herbicide, application rate, soil type, or conifer species. In agreement, soil microbial biomass and respiratory activity were unaffected by the herbicide treatments. The results show that these herbicides do not alter the capability of mycorrhizal fungi to infect roots, even at concentrations detrimental to seedling growth.

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39.
Cameron, I.R. 1988. An evaluation of the density management diagram for coastal Douglas-fir. BC Ministry of Forests FRDA-Report 024. vi + 17 p.

Keywords:      planting operations

                        growth

                        yield

Abstract: Yield predictions based on Drew and Flewelling's (1979) density management diagram for coastal Douglas fir (Pseudotsuga menziesii) were compared with remeasured plot data from British Columbia. The diagram overestimated standing volume by 64% and mean diameter by 24% on average. Volumes predicted for plantations established at initial densities between 300 and 3000 trees per hectare exceeded nearly all the plots in the database. Because of the unattainable production targets set by the diagram, strategic plans based on its predictions would be seriously in error. Consequently, the diagram cannot be used in its current form as a silvicultural planning tool in stands of Douglas fir on the coast of British Columbia.

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40.
Carr, W.W. 1987. Restoring productivity on degraded forest soils: two case studies. B.C. Ministry of Forests FRDA-Report 002. vi + 21 p.

Keywords:      site preparation

                        fertilization

                        tree physiology

                        growth

                        soil properties

Abstract: The use of green fallowing was studied at 2 sites, viz. (a) a coastal site at Koksilah, 15 km NW of Shawnigan Lake, British Columbia, where extensive subsoil exposure had resulted from roading operations in a highly productive Douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) stand, and (b) an inland site 30 km S. of Vanderhook including several landings and skid roads which had been deep-ripped to a depth of 50 cm, reducing soil density to 1350 kg/msuperscript 3. Plots at (a) were seeded in 1976 at 100 kg/ha with a grass/legume mixture including 3 spp. of Trifolium and Lotus corniculatus, and received NPK (10:30:10) at 450 kg/ha. Site nutrient levels improved substantially over 5 yr with N showing the greatest gains, and Douglas fir seedlings (1+2) planted in 1977 responded with increased foliar N and K contents and 300% greater ht. growth. Plots at (b) were seeded in 1981 at 40 kg/ha with a legume mixture of 3 spp. of Trifolium, Medicago sativa and L. corniculatus, and received NPK (19:19:19) at 300 kg/ha. Nutrient gains were found after 2 yr for P, K and especially N, and although foliar nutrient contents and growth of lodgepole pine (Pinus contorta) seedlings showed no increase, the enhancement of site nutrient capital is considered to be a gain likely to benefit commercial forestry production.

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41.
Carter, R. and K. Klinka. 1992. Use of ecological site classification in the prediction of forest productivity and response to fertilisation. South-African-Forestry-Journal (160): 19-23.

Keywords:      fertilization

growth
soil properties

Abstract: The results are presented of two related studies in southern coastal British Columbia. A total of 149 study plots in even-aged immature Douglas fir (Pseudotsuga menziesii) stands were categorized into 6 ecologically similar site associations (indicated best by climax plant communities) and into 15 soil moisture and soil nutrient combinations, for the prediction of site index. Fifty-one of these plots were used to predict basal area growth response to nitrogen fertilizer (225 kg N/ha as urea). Regression models indicated strong correlations between Douglas fir site index (m (height)/50 yr) and both indirect and direct measures of soil moisture and nutrient regimes (Rsuperscript 2 >0.72; p <0.01). Third-year basal area response to N fertilizer varied significantly among site associations (Rsuperscript 2 = 0.60; p <0.01). Site index also showed a significant relation with third-year basal area response (Rsuperscript 2 = 0.52; p <0.01), while the best predictive model included site associations and pretreatment foliar N and sulfate-S (Rsuperscript 2 = 0.64; p <0.01). It is suggested that the approach and methods of the study are applicable to predicting site-specific growth performance and response to fertilization of other tree species, including eucalypts.

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42.
Carter, R. and R. Scagel. 1989. The effects of stand density and fertilization on stand development in immature coastal Douglas-fir. B.C. Ministry of Forests FRDA-Report 094. i + 15 p.

Keywords:      fertilization

                        thinning

                        growth

                        tree morphology

Abstract: The effects of urea fertilizer were studied in Pseudotsuga menziesii stands spaced to 500, 750 and 1000 stems/ha in coastal British Columbia.

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43.
Carter, R.E. and R.P. Brockley. 1990. Boron deficiencies in British Columbia: diagnosis and treatment evaluation. Forest-Ecology-and-Management 37(1-3): 83-94.

Keywords:      fertilization

                        growth

                        tree/stand health

Abstract: Two case-studies are presented, outlining methods of diagnosis and treatment evaluation of boron deficiencies in a Douglas fir (Pseudotsuga menziesii) stand in coastal southern British Columbia and a lodgepole pine (Pinus contorta) stand near Burns Lake, in the interior of the province. Site conditions commonly associated with B deficiency are outlined, and relations between dormant-season foliar B concentration and growing-season precipitation and moisture stress are suggested. Diagnostic methods used in the study include examination of deficiency symptoms, and foliar-analysis techniques; evaluation of response for corrective fertilizer treatments is based on changes in frequency and severity of deficiency symptoms and growth responses, measured by graphical-analysis and changes in shoot length between treatments. Boron deficiencies and response to B fertilizers are difficult to confirm. Results of graphical-analysis and examination of frequency and severity of deficiency symptoms were inconclusive, while changes in shoot length identified a measurable response in the Burns Lake fertilizer trial with lodgepole pine. Deficiencies appear to be acute rather than chronic, and may not occur in untreated control trees for several years after establishment of fertilizer trials. Alternative causes for deficiency symptoms are also common, further complicating diagnosis and evaluation of response to treatment. It is concluded that all future trials should include nitrogen and/or other limiting nutrients with and without B to aid in identification of acute B deficiencies and deficiencies induced by increasing growth.

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44.
Carter, R.E., E.R.G. McWilliams and K. Klinka. 1998. Predicting response of coastal Douglas-fir to fertilizer treatments. Forest-Ecology-and-Management 107(1/3): 275-289.

Keywords:      fertilization

growth
soil properties

Abstract: A broadly-based, intensive Douglas-fir (Pseudotsuga menziesii) fertilizer experiment throughout southern coastal British Columbia (48 sites) was used to examine 3- and 6-yr crop tree growth responses to prescribed fertilizer applications (N alone, and N + additional nutrients identified as potentially deficient by foliar analysis). Absolute and relative basal area responses were evaluated in relation to site associations of the provincial ecosystem classification system, site index (SI), and a large number of site and stand chemical and physical properties. Few of the site and stand variables examined as possible response prediction criteria appeared to have any real utility. The strongest relationships found were between relative basal area response and (1) site index (Rsuperscript 2 0.46 for both 3- and 6-yr responses), (2) mineral soil mineralizable-N (Rsuperscript 2 0.50 and 0.46 for yr 3 and 6 responses, respectively), and (3) total mineralizable-N (Rsuperscript 2 0.47 and 0.50 for yr 3 and 6 responses, respectively). In all cases average relative response declined with increasing site quality. However, there were highly productive sites (SI50 <more or =>35 m) characterized by an absence of growing-season water deficits and relatively low foliar N concentrations (12-13 g/kg) which showed significant fertilizer responses. These sites are where the greatest financial returns from fertilizing may be realized. Relationships identified between site and stand variables and basal area responses were, in many cases, different from those found by other researchers for coastal Douglas fir. This brings the portability of identified relationships into question.

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45.
Carter, R.E., I.M. Miller and K. Klinka. 1986. Relationships between growth form and stand density in immature Douglas-fir. Forestry-Chronicle 62(5): 440-445.

Keywords:      planting operations
wood quality
tree morphology
growth

Abstract: Spacing was found to affect stem and crown characteristics and branching at whorls 6-10 in 27-yr-old Douglas fir established at 3 spacings (1.8x1.8, 3.6x3.6 and 4.6x4.6 m) near Haney, British Columbia. Ht., d.b.h. and stem diam. at the base of the live crown increased significantly with spacing, while age and ht. at the base of the live crown decreased. Increased spacing resulted in significantly greater branch diam. at whorls 6-10 and, in some whorls, an increase in branch number. Swelling of the stem at branch whorls, the number of Lammas whorls, knottiness ratio and a subjective index of stem form (where higher index indicated poorer form) increased with spacing. The selection of initial spacing is discussed and it is concluded that intensive management practices, e.g. thinning and pruning, will be necessary in all regimes if clear wood is to be produced over short rotations.

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46.
Castellano, M.A. and J.M. Trappe. 1985. Ectomycorrhizal formation and plantation performance of Douglas-fir nursery stock inoculated with Rhizopogon spores. Canadian-Journal-of-Forest-Research 15(4): 613-617.

Keywords:      nursery operations
growth
mycorrhizal response

Abstract: Basidiospores (0, 106, 107 or 108) of 7 species of hypogeous, ectomycorrhizal fungi were applied to 1-msuperscript 2 plots sown with 4 conifer species (Pseudotsuga menziesii, Pinus lambertiana, Abies concolor and Tsuga heterophylla) in a bare-root nursery in Oregon. Inoculation with either Rhizopogon vinicolor or R. colossus succeeded with 2 provenances of Douglas-fir only. For R. vinicolor, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings. For R. colossus, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings of one seed source, while the medium rate did better with the other. Stem height and root collar diameter of seedlings did not differ significantly between treatments and controls. Douglas-fir seedlings inoculated or not inoculated with spores of R. vinicolor were outplanted at 2 yr old in southwestern Oregon. After 2 yr, inoculated seedlings had significantly greater survival, stem height, root collar diameter, and biomass than noninoculated seedlings. Although new feeder roots of both noninoculated and inoculated seedlings were colonized by indigenous fungi, R. vinicolor persisted on the old root systems of inoculated seedings and colonized new feeder roots.

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47.
Castellano, M.A. and J.M. Trappe. 1991. Pisolithus tinctorius fails to improve plantation performance of inoculated conifers in southwestern Oregon. New-Forests 5(4): 349-358.

Keywords:      nursery operations

growth
mycorrhizal response

Abstract: Bare root seedlings of Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), white fir (Abies concolor), and grand fir (Abies grandis) were inoculated with Pisolithus tinctorius and subjected to standard nursery and cold storage practices. At age 2 years, seedlings were assessed for mycorrhizal status, and were planted out on a variety of sites in SW Oregon. After 1, 2 and 3 growing seasons root collar diameter and current year's shoot growth were measured (or a lateral branch if browsing had damaged main shoot). Results showed that inoculated seedlings performed no better than those which had not been intentionally inoculated but which had formed mycorrhizae with indigenous, nursery fungi (e.g. Thelephora terrestris, and possibly Inocybe spp.). Climate, planting sites and nursery practices in the Pacific Northwest differ drastically from those in the southeastern United States, where P. tinctorius has increased plantation survival and growth. It is concluded that further research is necessary on P. tinctorius and nursery inoculation of tree seedlings in the Pacific Northwest.

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48.
Chanway, C.P. 1997. Inoculation of tree roots with plant growth promoting soil bacteria: an emerging technology for reforestation. Forest-Science 43(1): 99-112.

Keywords:      nursery operations
tree/stand protection
growth

                        tree/stand health

                        mycorrhizal response

Abstract: Results from studies performed with beneficial asymbiotic tree root associated bacteria are reviewed in this article in relation to the possible uses of such microorganisms for artificial forest regeneration. The review includes sections on plant growth promoting bacteria for pine (Pinus spp.), spruce (Picea spp.), Douglas fir (Pseudotsuga menziesii) and hemlock (Tsuga heterophylla). Seedling root systems are colonized heavily by asymbiotic soil bacteria, many of which have the potential to influence plant growth significantly. A heterogeneous group of these microorganisms is well known for their ability to colonize roots and stimulate growth of agricultural plant species, sometimes doubling seedling biomass accumulation only a few weeks after inoculation, but more usually resulting in less spectacular biomass gains (e.g., 15%-30% greater than uninoculated controls within a growing season). Plant growth promoting soil bacteria may exert such effects through a variety of mechanisms, and include microorganisms that stimulate seedling emergence or infection by symbiotic fungi and bacteria. Other plant beneficial soil bacteria possess biological control activity or are capable of transforming plants genetically. Inoculation of tree seedlings with such bacterial before outplanting would be an inexpensive, environmentally benign, and easily applied nursery treatment, but comparatively little work has been performed with these microorganisms in forestry. Recent results with various tree species, however, indicate that seedling performance can be significantly enhanced through bacterial inoculation of root systems: pine and spruce biomass increased 32%-49% 1 yr after inoculation and outplanting at a reforestation site. In addition, infection by desired species of ectomycorrhizal fungi can also be enhanced by inoculation with certain strains of root colonizing bacteria.

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49.
Chanway, C.P., R.A. Radley and F.B. Holl. 1991. Inoculation of conifer seed with plant growth promoting Bacillus strains causes increased seedling emergence and biomass. Soil-Biology-and-Biochemistry 23(6): 575-580.

Keywords:      nursery operations

                        growth

                        tree morphology

Abstract: Seeds of lodgepole pine (Pinus contorta), Douglas fir (Pseudotsuga menziesii) and white spruce (Picea glauca) were collected from 3 sites in British Columbia. Inoculation with Bacillus strains L5 and L6 significantly increased the rate of seedling emergence of spruce but did not affect subsequent seedling growth. Pine root growth was promoted by strain L5 in sterilized, but not non-sterile, growth medium. Strain L6 promoted pine root growth in sterilized medium, but also caused significant increases in seedling emergence, shoot weight and height, root weight and surface area, and root collar diameter when tested in non-sterile peat-vermiculite medium. The positive effects due to a single inoculation of pine with strain L6 at sowing were not detectable after 12 weeks growth. However, root growth was stimulated after 16 weeks growth if seedlings were re-inoculated with strain L6 mid-way through the experiment. Shoot-growth promotion was also detected when 1-yr-old pine seedlings were planted in pots and inoculated with strain L6. Douglas fir seedlings grown from seed inoculated with strain L5 had increased root collar diameters, whereas those inoculated with strain L6 exhibited increased root surface area.

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50.
Chapman, R.J. 1984. Growth, nitrogen content and water relations of sludge-treated Douglas-fir seedlings. Forestry-Abstracts 45(7): 385-386.

Keywords:      fertilization
growth

                        tree physiology

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51.
Cochran, P.H., W. Lopushinsky and P.D. McColley. 1986. Effect of operational fertilization on foliar nutrient content and growth of young Douglas-fir and Pacific silver fir. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Note PNW-RN-445. 10 p.

Keywords:      fertilization

                        tree physiology

                        growth

Abstract: During 1979-80, sulfated urea (pelletted) was applied to conifer stands in the Wenatchee National Forest, west of Cle Elum, Washington. Nitrogen concn. in current needles of Pacific silver fir (Abies amabilis) showed a significant 1.9-fold increase after fertilizer treatment compared with a non-significant 1.3-fold increase in Douglas fir (Pseudotsuga menziesii). A significant 2.5-fold increase in foliar N also occurred in bracken (Pteridium aquilinum). Analysis of foliage from untreated trees indicated N deficiency in A. amabilis, but N concn. in Douglas fir was above threshold values. Fertilizer treatment did not affect foliar S in either species, but increased needle surface area for A. amabilis. Tree diam. growth, stand b.a. growth and vol. growth were all increased by fertilizer treatment.

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52.
Cole, D.W., M.L. Rinehart, D.G. Briggs, C.L. Henry and F. Mecifi. 1984. Response of Douglas fir to sludge application: volume growth and specific gravity. In Proceedings of the Technical Association of the Pulp and Paper Industry 1984 Research and Development Conference, Appleton, Wisconsin, September 30-October 3. pp. 77-84.

Keywords:      fertilization

                        thinning

                        growth

                        wood quality

Abstract: In 1977 and 1980 municipal sludge was applied to a 60-yr-old lowland Douglas fir stand in Washington State. Application procedures and rates and suitable sites for treatment are described. There was a 6 yr av. diam. growth response of 93% in unthinned and 48% in thinned stands treated with 142 t/ha sludge and a vol. growth response of 53 and 42%, respectively. The accelerated rate of growth has not shown signs of decreasing since treatment. Relative density of sludge-grown wood was 10-15% less than that of untreated wood, but within the range for Douglas fir grown on higher land. This is thought to be a result of the change in forest site produced by the sludge treatment.

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53.
Cole, E.C. and M. Newton. 1987. Fifth-year response of Douglas-fir to crowding and nonconiferous competition. Canadian-Journal-of-Forest-Research 17(2): 181-186.

Keywords:      release treatments

                        chemical release

                        growth

                        tree morphology

Abstract: Measurements were made in autumn 1982 in 5-yr-old plantations with trees spaced 17-123 cm apart, alone or with grass or red alder (Alnus rubra) on 3 site types in the Oregon Coast Range. Crowding and competition from both grass and alder reduced aboveground dry wt. per tree. Dry wt./ha was higher at higher tree densities, but this is expected to change with time as the larger trees at low densities form fully stocked stands. Grass showed the greatest effect on growth at the driest site. Although red alder decreased growth on all sites, the effect was most significant at the coastal site where light is most limiting and moisture least limiting. For the production of max. individual tree size, low stocking with control of competing vegetation is recommended.

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54.
Cole, E.C. and M. Newton. 1989a. Height growth response in Christmas trees to sulfometuron and other herbicides. Proceedings-of-the-Western-Society-of-Weed-Science (Vol. 42): 129-135.

Keywords:      release treatments

                        chemical release

                        growth

                        tree/stand health

                        stand conditions

Abstract: Abies procera, A. grandis and Pseudotsuga menziesii cv. Menziesii were evaluated for tolerance to sulfometuron (0.05-0.21 kg/ha), atrazine (4.5 kg/ha) and hexazinone (2.2 kg/ha). Herbicides were applied pre-budbreak and sulfometuron was also applied post-budbreak. Weeds were suppressed equally effectively by all rates and herbicides pre-em. Low rates of sulfometuron were less effective post-em. There was no significant damage to A. procera seedlings, although the highest rate of sulfometuron slowed growth significantly. A. grandis was not affected by any treatment. All treatments caused injury to 1-year-old P. menziesii, primarily needle chlorosis and slight stunting. Growth was best in atrazine-treated plots. For 3-year-old P. menziesii, injury was not significant but high rates of sulfometuron caused cosmetic damage. Best growth was observed with hexazinone and worst with sulfometuron. Post-budbreak applications and high rates of sulfometuron reduced growth more than pre-budbreak application and low rates.

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55.
Coleman, M., J. Dunlap, D. Dutton and C. Bledsoe. 1987. Nursery and field evaluation of compost-grown conifer seedlings. Tree-Planters' Notes 38(2): 22-27.

Keywords:      nursery operations

nursery fertilization
growth

tree physiology
tree/stand health

Abstract: Seedlings of Douglas fir (Pseudotsuga menziesii), noble fir (Abies procera) and ponderosa pine (Pinus ponderosa) were raised in beds that had been treated with 0, 2, 4 or 6 inches of compost (fir/hemlock sawdust and municipal sewage sludge, 3:1) at a nursery in Carson, Washington. In autumn 1983, the 2+0 stock was lifted, stored until spring 1984 and then planted out on Mt. St. Helens, Washington (Douglas fir), near Estacada, Oregon (noble fir) or E. of the Cascade crest near Leavenworth, Washington (ponderosa pine). Data are given on the ht., biomass and concn. of N, P, Zn, Cu, Pb, Ni and Cd after 1 yr in the nursery beds and on the ht. and survival for 2 yr after planting. The responses of the seedlings to the compost, the immobilization of nutrients and the accumulation of heavy metals are discussed.

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56.
Colinas, C., D. Perry, R. Molina and M. Amaranthus. 1994b. Survival and growth of Pseudotsuga menziesii seedlings inoculated with biocide-treated soils at planting in a degraded clearcut. Canadian-Journal-of-Forest-Research 24(8): 1741-1749.

Keywords:      planting operations

                        fertilization

                        growth

                        tree/stand health

                        tree morphology

Abstract: To determine the factors of transfer soils responsible for increased seedling survival and growth, planting holes, at a site in SW Oregon, were inoculated with forest, plantation, and clear-cut soils subjected to one of 8 treatments: (i) treated with fertilizer to test for effects of nutrients; treated with biocides to test for effects of (ii) grazers (microarthropods or nematodes), (iii) protozoa, (iv) fungi, or (v) bacteria; (vi) pasteurized; (vii) Tyndallized; or (viii) untreated. Douglas fir (Pseudotsuga menziesii) seedlings were planted in June 1990 and seedling growth and survival was assessed in December 1990. Survival was increased by inoculation with untreated plantation soils, but not if they were fertilized or treated with dimethoate + carbofuran (grazercide), fumagillin (protozoacide), or oxytetracycline + penicillin (bactericide). Addition of untreated forest soil did not increase survival. For all soils, survival was increased by captan (fungicide), pasteurization and Tyndallization. Untreated plantation and forest soil transfers increased dry weights whereas neither did when treated with dimethoate + carbofuran. Dry weights of seedlings given clear-cut soil were increased by fertilization, pasteurization and Tyndallization of the soil; the latter two treatments also increased the number of short roots. It is hypothesized that stimulation of seedling growth by soil transfers was related to an increased rate of nutrient mineralization due to microbivorous soil animals contained within the transfer soils. Soil transfers may have enhanced seedling survival by at least two mechanisms: (i) by providing a safe site for beneficial rhizosphere organisms to proliferate, free from competing organisms that have proliferated in the clear-cut soil; and (ii) through volatile organic compounds, especially ethylene, that stimulated seedling root growth.

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57.
Copes, D.L. 1980. Effect of root stock vigor on leader elongation, branch growth, and plagiotropism in 4- and 8-year-old Douglas-fir grafts. Tree-Planters' Notes 31(1): 11-14.

Keywords:      genetic tree improvement

                        tree grafting

                        growth

                        tree morphology

Abstract: In treatment (a) 2-yr-old seedling rootstocks were planted in containers in 1969 and scions from Oregon and Washington plantations grafted on in April 1970. The grafted trees were moved to transplant beds in Nov. 1970 and finally to field positions in Oregon in Dec. 1979. In treatment (b), rootstocks of the same age were bare-root planted in Nov. 1970 and scions grafted in April 1974. Graft growth was examined in May 1978. Field-grafted trees (b) showed upright tree form, significantly greater leader growth p.a. and longer branches in the 1976 whorl. Some 61% of container-grafted trees (a) showed a noticeable lean from vertical compared with none of the field grafted trees.

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58.
Copes, D.L. 1983. Failure of grafted Douglas-fir planted at Monterey, Calif. Tree-Planters' Notes 34(3): 9-10.

Keywords:      genetic tree improvement

                        tree grafting

                        growth

                        tree/stand health

                        tree phenology

Abstract: Trees were grafted onto established rootstocks (grown from rooted cuttings from Oregon or seedlings from California) in Oregon in April 1979, and in Dec. 109 of these were transplanted to a site on the Monterey Peninsula, California. Grafts were examined in July 1981. More than 30% of the transplanted grafts had died of early incompatibility and the cumulative 1980 and 1981 leader growth of the survivors averaged 12 cm. Identical grafts in Oregon showed 2-10% death due to incompatibility and av. leader growth of 1-2 m. It is suggested that the atypical unreliable budflush and reduced leader elongation in Monterey was due to winter temperatures that were not cool enough to satisfy bud dormancy requirements. It had been hoped to establish seed orchards out of range of pollen contamination from local Douglas fir stands.

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59.
Copes, D.L. 1999. Breeding graft-compatible Douglas-fir rootstocks (Pseudotsuga menziesii (MIRB.) FRANCO). Silvae-Genetica 48(3/4): 188-193.

Keywords:      genetic tree improvement

                        tree grafting

                        tree/stand protection

                        growth

                        tree phenology

                        tree/stand health

                        genetic relationships

Abstract: A study encompassing 24 years was conducted to determine if a breeding programme could produce highly graft-compatible rootstocks for P. menziesii. A total of 27 trees of apparent high graft compatibility were selected and crossed to produce 226 control-pollinated families. Seedlings were grown, field planted and grafted with test scions. Graft unions from field tests were evaluated anatomically for internal symptoms of incompatibility. Average compatibility of progeny from the 226 crosses was 90.6%, compared with 65% in native populations. Breeding values were calculated for each parent by the best linear prediction (BLP) procedure. Average compatibility resulting from crossing among the top 10 parents was estimated by breeding values as 95.4%. Field-test results of progeny from 34 crosses among the 10 most compatible parents showed 96% compatibility. In addition to field-tests for graft compatibility, nursery tests of seedlings from 124 crosses were evaluated for second-year vegetative bud flush and seedling height. It was possible, while maintaining adequately high levels of graft compatibility, to breed both for resistance to spring frost damage and for increased seedling height.

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60.
Crouch, G.L. and M.A. Radwan. 1981. Effects of nitrogen and phosphorus fertilizers on deer browsing and growth of young Douglas-fir. Pacific-Northwest-Forest-and-Range-Experiment-Station,-USDA-Forest-Service. Research-Note PNW-RN-368. 15 p.

Keywords:      fertilization

                        tree/stand health

growth
tree physiology

Abstract: N and P fertilizers were applied in March 1968 singly or in combination at a rate equivalent to 200 lb/acre of N or P to young trees (2-5 ft tall) in Oregon and Washington. Trees were examined and measured for up to 4 yr. In the first year after treatment trees given the N-only fertilizer in Washington were more heavily browsed by black tailed deer (Odocoileus hemionus columbianus), but this effect disappeared in the second year. Height growth was increased by N-only treatment in taller trees in Oregon after 1 and 2 yr, but the effect had disappeared after 4 yr. Total N content was significantly increased by the N and N + P treatments in the first year, but this effect also disappeared after 2 yr. The amounts of moisture, ash, Ca and P, and diam. growth were not affected by any treatments.

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61.
Curtis, R.O. 1987. Levels-of-growing-stock cooperative study in Douglas-fir: Report No. 9 - some comparisons of DFSIM estimates with growth in the levels-of-growing stock study. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-376. 34 p.

Keywords:      thinning

                        commercial thinning

                        growth

tree/stand health
computer modeling

Abstract: Initial stand statistics for the 9 levels-of-growing-stock (LOGS) study installations in Oregon and Washington, USA, and Vancouver Island, British Columbia, Canada, were projected by the Douglas fir (Pseudotsuga menziesii) stand simulation program (DFSIM) over the available periods of observation. Thinnings were simulated by use of observed top height trends, actual residual basal areas, and actual ratios of cut tree diameters to stand diameter before cutting (d/D). Estimates were compared with observed gross and net volumes and basal area growth, net change in quadratic mean diameter, and change in number of trees. Although the LOGS installations included regimes quite different from those in most of the data used to construct DFSIM, overall agreement was reasonably good. Results indicated some density-related bias in the thinned stands and a need for revision in the method used to control the maximum density in the DFSIM program and in the associated mortality estimates.

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62.
Curtis, R.O. and D.D. Marshall. 1986. Levels-of-growing-stock cooperative study in Douglas-fir. Report no. 8 - The LOGS study: twenty-year results. Pacific Northwest Research Station, USDA Forest Service Research-Paper PNW-RP-356. v + 113 p.

Keywords:      thinning

                        commercial thinning

                        growth

Abstract: A further report in a series on 9 study areas in Oregon, Washington and British Columbia. The programme aimed to determine relations between growing stock and vol., b.a. and diam. growth for 8 thinning regimes. Results presented are mainly from 5 site class II installations. Growth was strongly related to growing stock. Thinning treatments produced marked differences in volume distribution by tree sizes. There were considerable unexplained differences in productivity between installations, beyond those attributable to site quality. During the 4th treatment period (32-42 yr old in site class II sites) c.a.i. was approx. twice m.a.i. An evaluation is given of the LOGS study design.

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63.
Curtis, R.O. and D.D. Marshall. 2002. Levels-of-growing-stock cooperative study in Douglas-fir: report no. 14 - Stampede Creek: 30-year results. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-543. xi + 77 p.

Keywords:      thinning

                        commercial thinning

                        growth

                        yield

                        tree morphology

                        tree/stand health

Abstract: Results of the Stampede Creek installation of the levels-of-growing-stock (LOGS) study in Douglas-fir (Pseudotsuga menziesii) are summarized. To age 63 (planned completion of 60 feet of height growth), volume growth on the site III natural stand has been strongly related to level of growing stock, but basal area growth-growing stock relations were considerably weaker. Marked differences in tree size distributions have resulted from thinning. Periodic annual volume increments at age 63 are two to three times greater than mean annual increment; this stand is still far from culmination. Results for this southwest Oregon installation are generally similar to those reported from other LOGS installations, although development has been slower than on the site II installations that make up the majority of the series.

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64.
Curtis, R.O., D.D. Marshall and J.F. Bell. 1997. LOGS: a pioneering example of silvicultural research in coast Douglas-fir. Journal-of-Forestry 95(7): 19-25.

Keywords:      thinning

                        commercial thinning

                        growth

                        yield

Abstract: A regional levels-of-growing-stock (LOGS) study of young Douglas fir (Pseudotsuga menziesii) stands in western Oregon and western Washington, USA and Vancouver Island, British Columbia, Canada, was conducted between 1961 and 1970. The objective was to determine how the amount of growing stock retained in repeatedly thinned stands of P. menziesii affects cumulative wood production, tree size and growth:growing stock ratios. Nine LOGS installations were established during the study period, each consisting of 27 one-fifth acre plots, with 8 thinning treatments (and controls). All plots received initial calibration thinning. After the first 10 feet of height growth and at intervals of 10 feet thereafter, 5 subsequent thinning treatments were made. As of 1994, all installations on site class II, and most installations on site classes III and IV had completed the planned thinning sequence over 60 ft of height growth. Periodic annual increment of both basal area and volume was clearly related to basal area of growing stock and several measures of density. Thinning accelerated diameter growth, and diameter and volume distributions differed greatly among treatments. Mean annual increment and periodic annual increment showed no sign of approach to culmination in either total or merchantable cubic volume. Cumulative volume production (live stand plus thinning) of the controls exceeded all thinning treatments to date when measured in total cubic volume of all trees, although when volume was measured in merchantable cubic feet several thinning treatments exceeded net volume production of the controls. A discussion of the results includes: a comparison with other thinning studies; an analysis of application of the Langsaeter hypothesis (that the same cubic volume production could be obtained over a wide range of stand densities); growth trends and rotations; thinning gains; non-timber values; and critical analysis of the study design. The continuing value of the demonstration stands is discussed.

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65.
Dangerfield, J. and H. Brix. 1981. Comparative effects of ammonium nitrate and urea fertilizers on tree growth and soil processes. In Proceedings: Forest Fertilization Conference, University of Washington, Seattle, Washington, USA. Eds. S.P. Gessel, R.M. Kenady and W.A. Atkinson. pp. 133-139.

Keywords:      fertilization

                        thinning

                        growth

                        tree physiology

Abstract: Growth response of Douglas-fir to ammonium nitrate and urea, applied at rates of 200 and 400 pounds per acre (224 and 448 kilograms of nitrogen per hectare), was studied over a 7-year period at Shawnigan Lake, B.C. Diameter growth was 21 and 9 percent better, respectively, for the two rates with ammonium nitrate than with urea in unthinned plots and 7 percent better for plots that had been thinned and received 400 pounds per acre (448 kilograms nitrogen per hectare). Foliar nitrogen concentrations also increased most with ammonium nitrate fertilzization during the first 2 years, indicating that nitrogen from this source was initially more readily available to the trees. This is explained in part by the greater mobility of nitrate supplied by ammonium nitrate and by nitrogen immobilization in buildup of bacterial populations with urea.

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66.
DeBell, D.S., C.A. Harrington and J. Shumway. 2002. Thinning shock and response to fertilizer less than expected in young Douglas-fir stand at Wind River Experimental Forest. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-547. ii + 20 p.

Keywords:      fertilization

                        thinning

                        precommercial thinning

                        growth

Abstract: Three thinning treatments (thinned to 3.7 by 3.7 m, thinned to 4.3 by 4.3 m, and an unthinned control treatment with nominal spacing averaging 2.6 by 2.6 m) were installed in a 10-year-old Douglas-fir (Pseudotsuga menziesii) plantation growing on a low-quality site at the Wind River Experimental Forest in southwest Washington, USA. Two years after thinning, two fertilizer treatments were superimposed on the design (0 and 224 kg per ha of nitrogen applied as ammonium nitrate). Diameter growth increased with increasing spacing throughout the 6-year study period, and it was also increased by fertilizer in both the thinned and unthinned (control) treatments. Thinning shock, a reduction in height growth after thinning, was expected at this study site because severe thinning shock had been documented in earlier nearby trials. Height growth was initially reduced slightly by thinning, but by the third 2-year period after thinning, height growth in thinned, unfertilized treatments was equal to or greater than height growth in the unthinned, unfertilized treatment. Fertilizer application increased height growth on average by 13 per cent in the first 2 years after fertilizer application. In the third and fourth years after fertilizer application, however, fertilizer increased average height growth by 9 per cent, but the increase was substantial (16 per cent) only in the unthinned control treatment. The mild, ephemeral nature of thinning shock in our study was in contrast to the severe, long-lasting shock in earlier studies at Wind River. The milder shock in our study could be related to one or more of the following: (1) thinning was done at an early age, (2) impacts of fire (natural or prescribed) preceding planting were minor, and (3) seed source of the planted stock was appropriate for the location. Based on comparisons with other studies at Wind River and elsewhere, we suspect that use of nonlocal, maladapted seed sources in the earlier studies may have predisposed those trees to thinning shock. Furthermore, we suspect that the much higher responses to fertilizer application reported in the earlier studies may be associated with intense natural fires prior to planting, and the reduced nutritional status of those sites may have been further exacerbated by the use of maladapted seed sources.

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67.
DeBell, D.S., R.R. Silen, M.A. Radwan and N.L. Mandel. 1986. Effect of family and nitrogen fertilizer on growth and foliar nutrients of Douglas-fir saplings. Forest-Science 32(3): 643-652.

Keywords:      fertilization

                        growth

                        tree physiology

Abstract: Urea (224 kg N/ha) was applied to 12-yr-old Douglas fir of 12 open-pollinated families growing near Corvallis, Oregon. Ht. and d.b.h. were measured before fertilization in Feb. 1979 and 4 growing seasons later, and tree vol. were estimated. Vol. increment varied among families, but was increased by an av. 7% by fertilizer. Concentrations of foliar nutrients, analysed in winter 1979 and 1980, differed significantly between families and in response to fertilization. The familyxfertilizer interaction was not significant for any growth or foliar nutrient measured.

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68.
Dimock, E.J., II and E.B. Collard. 1981. Postplanting sprays of dalapon and atrazine to aid conifer establishment. Pacific-Northwest-Forest-and-Range-Experiment-Station,-USDA-Forest-Service Research-Paper PNW-RP-280. iii + 16 p.

Keywords:      release treatments

                        chemical release

                        growth

                        tree/stand health

                        stand conditions

Abstract: A mixture of dalapon and atrazine at 8 and 4 lb/acre, respectively, or dalapon or atrazine alone were applied to control perennial grasses and forbs competing with newly planted seedlings of ponderosa pine and Douglas fir. In 4 studies in Oregon in 1975, herbicides were spot sprayed around individual seedlings. In 2 studies in Washington and Oregon in 1976, herbicides were broadcast sprayed. The mixture consistently controlled grass and forbs better than either herbicide alone, reducing grass and forb cover respectively by 80-82% and 48-58% in the first year. Control persisted for 2-4 yr. Varying results are reported as to the effects of the different treatments on height growth and survival.

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69.
Donald, D.G.M. and D.G. Simpson. 1985. Shallow conditioning and late fertilizer application effects on the quality of conifer nursery stock in British Columbia. B.C.-Ministry-of-Forests Research-Note 99. viii + 36 p.

Keywords:      nursery operations

                        nursery fertilization

                        tree/stand protection

                        tree morphology

                        tree/stand health

                        growth

Abstract: Eight trials on 2+0 stock of Picea engelmannii, P. glauca, P. sitchensis, Pinus contorta and Pseudotsuga menziesii (var. glauca and var. menziesii) in 4 nurseries were conducted to compare the effects of shallow conditioning (undercutting and wrenching at 10 cm deep) with those of the standard conditioning regime (undercutting and wrenching at 20 cm) on nursery performance, storage and field performance. The application of a complete NPK fertilizer 50 days before lifting was also evaluated. Shallow conditioning and late fertilizer application improved the root growth capacity at lifting, but could not replace cold exposure for hardening Pseudotsuga menziesii. Shallow conditioning had little effect on survival after planting and reduced initial ht. increment of all species. Application of fertilizer just before lifting improved the early growth of the trees without adversely affecting survival. Planting seedlings some 5 cm deeper than they stood in the nursery improved establishment.

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70.
Dosskey, M.G., L. Boersma and R.G. Linderman. 1993. Effect of phosphorus fertilization on water stress in Douglas fir seedlings during soil drying. Plant-and-Soil 150(1): 33-39.

Keywords:      fertilization

                        tree/stand protection

                        growth

                        tree physiology

                        photosynthesis

Abstract: A growth chamber experiment was conducted to determine if P fertilizing to enhance the P nutrition of otherwise N and P deficient Douglas fir (Pseudotsuga menziesii) seedlings reduces water stress in the seedlings during drought periods. Seedlings were grown in pasteurized mineral soil under well watered conditions and fertilized periodically with a small amount of nutrient solution containing P at three levels: 0, 20, or 50 mg/litre. By age 6 months, leaf nutrient analysis indicated that N and P were deficient in control (0 mg P/litre) seedlings. The highest level of P fertilizer, which doubled leaf P concentration, did not affect plant biomass, suggesting that N deficiency was limiting growth. When these seedlings were subjected to drought, there was no effect of P fertilizing on leaf water potential or osmotic potential. Furthermore, P fertilized seedlings had lower stomatal conductance and net photosynthesis rate. These results indicate that enhanced P nutrition, in the presence of N deficiency, does not reduce water stress in Douglas fir seedlings during drought periods.

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71.
Drew, A.P. 1983. Optimizing growth and development of 2-0 Douglas-fir seedlings by altering light intensity. Canadian-Journal-of-Forest-Research 13(3): 425-428.

Keywords:      nursery operations

                        tree/stand protection

                        growth

                        tree morphology

                        carbon allocation

Abstract: Seedlings were grown outdoors in Michigan in pots under 71% of full light the first growing season and full light the second. Another group of seedlings was given full light continuously for 2 yr. At the end of the 1st year, seedlings given initial shade had grown larger in total wt. (root + shoot) than those grown under full light. With removal of shading, the larger plants began to allocate increased dry matter to root development relative to their shoots. By the end of 2 yr, shoot/root ratios for the 2 groups were no different, yet the plants shaded in their 1st year were significantly heavier (dry wt.) By proper use of shading during development, larger 2+0 planting stock with good root development may be produced. Such stock, grown without the use of costly fertilizer, may be better suited to regeneration of droughty sites in the Pacific Northwest USA than the usual 2+0 planting stock, nursery grown under full light.

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72.
Driessche, R.v.-d. 1983. Growth, survival, and physiology of Douglas-fir seedlings following root wrenching and fertilization. Canadian-Journal-of-Forest-Research 13(2): 270-278.

Keywords:      nursery operations

                        nursery fertilization

                        tree/stand health

                        tree morphology

                        tree physiology

                        growth

Abstract: Seedlings at different nurseries on Vancouver Island were subjected to wrenching treatments during their 2nd year of growth using a fixed blade at 20-25 cm below the bed surface. In the first experiment, wrenching reduced water potential of trees on unirrigated loam soil by an av. of 300 kPa during Aug. and Sept. Wrenched trees lifted in Oct. and stored at 2 degrees C until May, showed 25% higher survival than unwrenched trees 1 yr after planting. Trees lifted in Dec. had uniformly high survival (98%) and showed no effect of wrenching. Wrenched trees from irrigated plots had lower shoot length relative growth rates (RGR) than unwrenched trees during the year after planting. In the second experiment, wrenching treatments were applied to seedlings, growing in a loamy sand, for different periods between 15 May and 11 Sept. as follows: (a) no wrenching, (b) early summer, (c) midsummer, (d) late summer and (e) all summer. Three fertilizer treatments (none, and 2 amounts of NPK) were applied to each wrenching treatment, and seedlings were lifted for storage at 2 degrees C in Oct. and Dec. Stored trees and freshly lifted trees were planted at 700 m alt. on 3 March. Wrenching increased root dry wt., particularly when additional fertilizer was applied, but had no measurable effect on cold hardiness or root growth capacity. Nevertheless, late summer wrenching increased survival 5 and 7% above control 1 and 2 yr after planting. Wrenching had little subsequent effect on new shoot growth of planted trees during the 2 yr after planting. However, late-summer wrenched trees showed significantly more new shoot growth than all-summer wrenched trees. More fertilizer reduced cold hardiness and survival of cold-stored trees, but increased root growth capcity. Cold hardiness (measured by electrical impedance) was correlated with survival of cold-stored trees after planting (rsuperscript 2 = 0.82). Root growth capacity, averaged over all fertilizer treatments was closely correlated with survival of stored and freshly lifted trees (rsuperscript 2 = 0.93). Foliar nutrient concn. were reduced by wrenching, but fertilizing increased nutrient reserves within the seedling.

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73.
Driessche, R.v.-d. 1984a. Response of Douglas fir seedlings to phosphorus fertilization and influence of temperature on this response. Plant-and-Soil 80(2): 155-169.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

                        carbon allocation

                        tree morphology

Abstract: In pot experiments levels of P fertilizers equivalent to 300 kg/ha were adequate for maximum growth of Douglas fir (Pseudotsuga menziesii var. menziesii) seedlings over 14-18 weeks, and resulted in available soil P levels of 80 ppm after 15 weeks' growth. Maximum growth in pots was obtained with shoot P concentrations of 0.18%-0.20%, with higher values at lower temperatures, but the optimum concentration for one-year-old (1-0) nursery seedlings was 0.16% P. Growth of seedlings was greatly restricted at a soil temperature of 5 degrees C and an air temperature of 12 degrees C. At a soil temperature of 10 degrees C and an air temperature of 14 degrees C seedling P requirement was greater than at soil and air temperatures of 20 degrees C. Monoammonium phosphate was more effective than calcium superphosphate in stimulating growth in pots and nursery beds. Triple superphosphate was also effective in the nursery. Diammonium phosphate, potassium dihydrogen phosphate and phosphoric acid had no advantages as P sources in the nursery. Available P levels of 100-130 ppm, in the loamy sand and sandy loam nurseries studied, and needle P concentrations of 0.18%, when sampled in October, were associated with maximum growth of two-year-old (2-0) seedlings. P fertilization decreased the root/shoot ratio, but did not alter the allometric relationship of shoot to root. Improving the P status from a low level increased the root growth capacity in 2-0 seedlings and P fertilization of potted seedlings increased the dry weight/height ratio. Uptakes per seed bed ha of 236 kg N, 31 kg P, 81 kg K and 73 kg Ca by 2-0 seedlings were comparable with, or greater than, uptake rates of agricultural crops. Recoveries of 6-11% of P from fertilizer were recorded in the nursery.

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74.
Driessche, R.v.-d. 1984b. Seedling spacing in the nursery in relation to growth, yield, and performance of stock. Forestry-Chronicle 60(6): 345-355.

Keywords:      nursery operations

                        growth

                        tree morphology

                        carbon allocation

                        tree physiology

                        tree/stand health

Abstract: In 3 experiments at nurseries in coastal British Columbia Picea sitchensis, P. glauca, Pinus contorta var. latifolia, Thuja plicata and coastal and interior varieties of Pseudotsuga menziesii were sown in May 1979, 1980 or 1982 and grown at spacings ranging from 0.5 to 12 cm. A 1-cm increase in spacing increased seedling dry wt. by 0.5-1.5 g and root collar diam. by 0.2-0.25 mm up to a spacing of about 8-10 cm. Above this, response was less. Ht. of 2-yr-old seedlings was increased slightly or even decreased by wider spacing. Height : diameter ratios decreased sharply and shoot : root dry wt. decreased or remained unchanged with wider spacing. The number of needle primordia in 2-0 P. menziesii buds increased up to a spacing of 2 cm, and the number of 1st and 2nd order branches were also increased by wider spacing. Increases in root growth capacity were associated with wider spacing in T. plicata and Picea sitchensis. In a test of 3 types of precision seeders, none produced anything like accurate seed placement. Irregularity was increased by 10-20% non-viable seed and winter mortality. Increased spacing of 2-5 cm between seedlings was justified by the yield of acceptable seedlings only when the culling standard was increased to a root collar diam. of about 6 mm. Three yr after planting out the survival of P. glauca was increased 11% by wider spacing. After 2 yr P. sitchensis survival was increased 13% by wider spacing. Both species grown at wider spacing maintained a ht. and diam. advantage over those from close spacing.

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75.
Driessche, R.v.-d. 1988a. Nursery growth of conifer seedlings using fertilizers of different solubilities and application time, and their forest growth. Canadian-Journal-of-Forest-Research 18(2): 172-180.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        carbon allocation

                        tree physiology

                        tree/stand health

Abstract: Beginning in May 1982, seedlings of Douglas fir and white spruce were grown for 2 yr in a bare-root nursery in southern British Columbia. Seedlings were treated with four types of commercial fertilizers (slow-release Osmocote, ammonium phosphate, ammonium sulphate and Hi-Sol, a soluble fertilizer with 20-20-20 NPK) at 2 different frequencies during both years to give total N applications of 0, 210 or 350 kg/ha. In addition, Douglas fir seedlings that had been grown for 2 yr without fertilizer were treated with the same amounts of fertilizer as a late season treatment during 1 Sep.-20 Oct. 1983. Ammonium fertilizers produced larger seedlings than Osmocote and Hi-Sol. Dry wt. increased with application rate, but frequency of application had only a small effect. Fertilizer increased the proportion of stem dry matter and decreased the proportion of needle and root dry matter. Dry wt. of 2+0 white spruce seedlings was correlated with soil pH, extractable NO3 and available P measured in Sep. of the first growing season. Douglas fir seedlings were planted out in Mar. 1984. Late-season fertilized seedlings had greater N and P tissue concn. than seedlings fertilized during the growing season. Survival and growth rate after planting were also both greater in late-season fertilized seedlings. Results suggested that fertilizer composition was more important than fertilizer solubility for nursery growth.

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76.
Driessche, R.v.-d. 1988b. Response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to some different fertilizers applied at planting. New-Forests 2(2): 89-110.

Keywords:      nursery operations

                        nursery fertilization

                        fertilization

                        growth

                        tree/stand health

                        tree physiology

Abstract: Four fertilizer experiments to assess type of fertilizer, dosage and timing, were conducted on eastern Vancouver Island, BC, Canada. Two-yr-old, bare root planting stock was used except in experiment 3, where container stock was compared with bare root stock. Little growth response was obtained after one year, but height growth responses of 12 to 31% were measured after 3 to 6 yr with fertilizers supplying 8.4 to 16.8 g N per tree. Growth responses were little affected by type of fertilizer and were primarily due to N, with release rate having no marked effect. The exception to this was triple superphosphate which did not increase growth but did increase survival. Survival was reduced by ammonium sulphate and to a lesser extent by Agriform (NPK). Container seedlings responded more to fertilization at planting than bare root seedlings. Seedling N, P and K concn. and contents declined following planting for 6 months and only started to recover after July. Application of fertilizer caused a small increase in seedling nutrient concn. regardless of date, but this had no detectable effect on dry weight measured 6 wk later.

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77.
Driessche, R.v.-d. 1991a. Influence of container nursery regimes on drought resistance of seedlings following planting. I. Survival and growth. Canadian-Journal-of-Forest-Research 21(5): 555-565.

Keywords:      nursery operations

                        tree/stand protection

                        growth

                        tree morphology

                        carbon allocation

                        tree/stand health

Abstract: In a 2 year study, Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta) and white spruce (Picea glauca) seedlings, grown in Styroblock containers in a container nursery from February to July 1988, were exposed to three temperatures and three levels of drought stress applied factorially during 18 July to 29 September 1988. Mean temperatures of 13, 16 and 20 degrees C were imposed in growth chambers, in a cooled plastic house, and in an ambient plastic house, respectively. Control, medium and severe levels of drought stress were imposed in a series of eight cycles, resulting in mean xylem pressure potentials of -0.32, -0.50 and -0.99 MPa, respectively. Seedlings were kept in the ambient plastic house until January 1989, when they were lifted and cold-stored until transplanting to covered 0.5-m deep sand beds, which provided hygric, mesic, and xeric conditions for testing all species and treatments. At the end of nursery growth, an increase in nursery temperature increased height and height : diameter ratio in all species and shoot:root dry weight ratio in Douglas fir and lodgepole pine. Increase in temperature also increased the number of seedlings with large well-formed buds in white spruce, but reduced the number in Douglas fir. Drought stress reduced height and dry weight in all species and bud length in lodgepole pine. After 9 weeks in sand beds, low nursery temperature increased survival (19% for lodgepole pine and white spruce grown in the xeric bed), except for Douglas fir grown in the xeric bed. Nursery drought stress also increased survival (16% for Douglas fir and lodgepole pine in the xeric bed), but had little effect on white spruce. Low temperature and drought stress treatments that increased survival also reduced height and dry weight of lodgepole pine and white spruce after one growing season in sand beds. Survival showed significant negative correlations with height, dry weight and height:diameter and shoot : root weight ratios. Low nursery temperature continued to affect growth 16 weeks after planting, increasing relative growth rate and allometric ratio (K) of Douglas fir and reducing K of white spruce.

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78.
Driessche, R.v.-d. 1992a. Absolute and relative growth of Douglas-fir seedlings of different sizes. Tree-Physiology 10(2): 141-152.

Keywords:      nursery operations

                        growth

Abstract: Douglas fir (Pseudotsuga menziesii) seedlings of a single (Vancouver Island) seed source were grown in a nursery on Vancouver Island, British Columbia, Canada, for two years to produce five different bare rooted stock types through varying spacing and transplanting treatments: spacing of 1.2, 7.7 and 14.3 cm; 14 cm 1+1 transplant; and 14 cm container transplant. They were then planted in the forest together with one-year-old container seedlings of the same seed source (a sixth treatment). Stem volume mean relative growth rate (Rv) was low immediately after planting for all stock types except the container seedlings, and increased over the following 7.6 years. An 8-week greenhouse test of the six stock types showed that dry weight mean relative growth rate (Rw) generally decreased with seedling dry weight, but this effect was less obvious after planting because only the three smaller stock types showed a decrease in Rw with size. In another experiment, bare root Douglas fir seedlings were grown at five different spacings (1.9, 2.8, 5.0, 7.4 and 10.6 cm) in a nursery for two years, and seedlings from each spacing treatment were sorted into 'large' or 'small' by height. Resulting 10 treatments were outplanted and stem volumes determined over 6.7 years. Effect of nursery spacing on stem volume was linear up to 3.6 years after planting, but large seedlings had greater stem volume than small seedlings throughout the 6.7 years of the study. There was no indication that Rv decreased with time, but small seedlings had a greater Rv than large seedlings. Relative growth rates of 2-year-old Douglas fir were depressed for a year or two after planting, but then remained relatively constant, or increased during the ensuing 5 years. Relative growth rates of smaller seedlings were greater than those of larger seedlings so that relative biomass differences decreased with time, and the time advantage of larger stock decreased. Absolute size differences increased with time.

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79.
Driessche, R.v.-d. 1992b. Changes in drought resistance and rootgrowth capacity of container seedlings in response to nursery drought, nitrogen, and potassium treatments. Canadian-Journal-of-Forest-Research 22(5):740-749.

Keywords:      nursery operations

                        nursery fertilization

                        tree/stand protection

                        tree/stand health

                        growth

                        carbon allocation

                        tree physiology

Abstract: Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), and white spruce (Picea glauca) seedlings, each represented by two seed lots, were grown in Styroblock containers in a greenhouse and plastic shelter house from February 1989 to January 1990. The seedlings were exposed to two N treatments (20 and 200 mg/litre) and three K treatments (5, 25 and 100 mg/litre) arranged factorially within three drought treatments. After winter storage, seedlings from a complete set of treatments were planted into hygric, mesic and xeric sand beds during 12-14 March. Increasing nursery drought stress increased survival of Douglas fir and lodgepole pine after planting, and high N treatment level increased survival of lodgepole pine and white spruce. Under xeric conditions, combined nursery drought and high N treatments increased survival of lodgepole pine by 33%, indicating the importance of nursery cultural regime for stock quality. Increase in nursery drought stress did not decrease seedling size by much; increase in N increased seedling size one season after planting. A positive relation between shoot : root ratio and survival in lodgepole pine and white spruce indicated that increase in N increased both shoot growth and drought resistance over the N range investigated. Only Douglas fir showed an interaction between drought and N treatment and a small response in both survival and dry weight to K application. Root growth capacity, measured at the time of planting, showed an approximate doubling in all species due to high N treatment, and was also increased in white spruce by drought stress. Survival and root growth capacity were poorly correlated, but dry-weight growth in sand beds was well correlated with root growth capacity. Shoot dry weight and percentage N in shoots measured after nursery growth were correlated with root growth capacity. Manipulation of root growth capacity by changing nursery treatment was possible without altering resistance to drought stress after planting.

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80.
Dunsworth, B.G. 1985. Three-yr survival and height growth of 2+0 bareroot Douglas-fir seedlings treated with a Symbex root dip. Tree-Planters' Notes 36(1): 24-25.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree/stand health

Abstract: Seedling roots were dipped in a sol. of Symbex [a stimulant containing fertilizer and microorganisms?] diluted 40:1 with water, or water before planting out in May 1980 on Vancouver Island, British Columbia. Although the ht. growth of Symbex-treated trees was significantly greater in 1981, there were n.s.d. in total ht., ht. growth or survival after 3 growing seasons.

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81.
Dunsworth, B.G. 1988. Douglas-fir fall root phenology: a bioassay approach to defining planting windows. In Proceedings: 10th North American Forest Biology Workshop, 'Physiology and genetics of reforestation', University of British Columbia, Vancouver, British Columbia, July 10-22, 1988. Eds. J. Worrall, J. Loo-Dinkins and D.P. Lester. pp. 295-307.

Keywords:      planting operations

                        growth

                        tree/stand health

                        tree phenology

Abstract: Natural seedling root phenology during the autumn and spring was observed in Douglas fir [Pseudotsuga menziesii] and western hemlock [Tsuga heterophylla] over several seasons on Vancouver Island, British Columbia. These observations were used to determine the soil climate conditions under which peak activity occurred. Mitotic indexing and total root tip counts were used to quantify root activity. Peak activity for both spring and autumn in both species could be reasonably bracketed by soil climate conditions of -1 bar soil tension and 4 degrees C. The hypothetical planting window defined by these soil climate conditions was then tested with a series of timing of planting studies for Douglas fir (autumn) and western hemlock (spring) containerized stock. The results indicated that although quality of planting stock and the season following planting are influential, a 10 to 15% survival and growth advantage can be gained by planting within the hypothetical window.

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82.
Duponnois, R., J. Garbaye, D. Bouchard and J.L. Churin. 1993. The fungus-specificity of mycorrhization helper bacteria (MHBs) used as an alternative to soil fumigation for ectomycorrhizal inoculation of bare-root Douglas-fir planting stocks with Laccaria laccata. Plant and Soil 157:257-262.

Keywords:      nursery operations

                        growth

                        mycorrhizal response

Abstract: Mycorrhization helper bacteria (MHBs) isolated and selected from the Douglas fir (Pseudotsuga menziesii)-Laccaria laccata symbiotic system have previously been shown to be fungus-specific: they promote ectomycorrhizal establishment of Laccaria laccata but inhibit mycorrhizal formation by other fungi. In this paper, two experiments in a nursery producing 2-yr-old bare rooted Douglas fir planting stock confirmed the specificity of MHBs (9 strains were tested) under field conditions. Mycorrhizal formation by Laccaria laccata, and the closely related L. bicolor was promoted by the specific MHBs tested, but mycorrhizal formation by Hebeloma cylindrosporum and a contaminant white fungus was inhibited; the strain of Paxillus involutus used was only poorly infective and not affected by MHBs. The experiments also showed that, by selectively helping the introduced L. laccata against the resident symbionts, MHBs are an interesting alternative (safer and easier) to soil fumigation for the success of routine controlled mycorrhization of planting stock in forest nurseries. The MHB strain BBc6 (a Pseudomonas fluorescens) is suggested as a suitable candidate for this system.

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83.
Duryea, M.L. and S.K. Omi. 1987. Top pruning Douglas-fir seedlings: morphology, physiology, and field performance. Canadian-Journal-of-Forest-Research 17(11): 1371-1378.

Keywords:      nursery operations

                        nursery pruning

                        tree phenology

                        tree/stand health

                        growth

                        yield

Abstract: Seedlings from 9 seed sources at 6 nurseries in Washington, Oregon and California were treated with various pruning treatments including tall and short ht. (25 and 15 cm, respectively), early and late timing (6 wk after bud burst or 6 wk after bud set, respectively), pruning twice or no pruning. Seedlings were evaluated for phenology and quality, and graded in the nursery. For each seed source, seedlings were planted at field sites in their own zone and on one common site. Seedlings pruned tall and early began growing again within 5 wk and set buds 2 wk later than unpruned seedlings. Shippable yield of seedlings pruned tall and early and of unpruned seedlings were n.s.d, although more pruned seedlings had multiple leaders. Pruned seedlings were smaller than unpruned seedlings at the time of planting. Survival and growth were the same for pruned and unpruned seedlings in the 1st year after planting. Pruned seedlings grew more than unpruned seedlings in the 2nd year, but were still shorter after 2 yr. Field growth was greater in seedlings pruned tall or early than in seedlings pruned short or late. It is concluded that pruning should be continued as a cultural practice if it benefits nurseries, but that late short pruning should be avoided.

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84.
Edgren, J.W. 1981. Field performance of undercut coastal and Rocky Mountain Douglar-fir 2+0 seedlings. Tree-Planters' Notes 32(3): 33-36.

Keywords:      nursery operations

                        tree/stand health

                        growth

Abstract: Seedlings from 1 seed source each of Pseudotsuga menziesii var. menziesii (coastal) and P. menziesii var. glauca (Rocky Mountain) were grown in a nursery in Washington and half were undercut at 15 cm below the surface at 1-yr-old. Seedlings were lifted in March the next yr (1968) and planted out at 2 sites in Oregon. Survival of undercut coastal firs 3 yr after planting was significantly better than controls. Survival of Rocky Mountain fir was not significantly affected by undercutting. Ht. growth of control seedlings of both varieties was significantly greater in their 1st season than that of undercut seedlings, but the differences disappeared the following year.

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85.
Edmonds, R.L. and T. Hsiang. 1987. Forest floor and soil influence on response of Douglas-fir to urea. Soil-Science-Society-of-America-Journal 51(5): 1332-1337.

Keywords:      fertilization

                        thinning

                        growth

                        soil properties

Abstract: Data from the Regional Forest Nutrition Research Project (RFNRP) in Washington and Oregon were analyzed to improve stand-specific prediction of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] response to urea fertilization. The response variable (relative difference in volume growth between fertilized and control plots 4 yr after fertilization with 448 kg N/ha) was regressed against 28 stand and site variables (e.g., age, elevation, forest floor C/N ratio, soil cation exchange capacity, etc.) using stepwise multiple regression analysis. Data from 120 installations were stratified by thinning level (thinned or unthinned), geographic location (provinces), and site quality (site index and class). Forest floor C/N ratio was the dominant variable related to response. In thinned installations of high site quality (site classes 1 and 2), 60% of variation in response was explained by the forest floor C/N, and 75% of the variation in response was explained with inclusion of surface soil exchangeable K. In thinned, low site quality stands, response was not as well related to forest floor C/N. Analysis of the data by province indicated that S may be limiting in southwest Oregon and P in coastal Washington.

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86.
El Kassaby, Y.A. and Y.S. Park. 1993. Genetic variation and correlation in growth, biomass, and phenology of Douglas-fir diallel progeny at different spacings. Silvae-Genetica 42(6): 289-297.

Keywords:      genetic tree improvement

                        nursery operations

                        genetic relationships

                        growth

                        carbon allocation

                        tree phenology

Abstract: Parents of coastal Douglas fir (Pseudotsuga menziesii) selected from natural stands on sites ranging from 0 to 450 m altitude on Vancouver Island and in southeastern British Columbia were crossed and the resulting 104 full-sib families evaluated for 3 years after germination. The full-sib families were produced by a disconnected diallel mating scheme, consisting of 7 sets of 6-parent partial diallels, grown under 2 spacing treatments in a nursery. The objectives of the study were to determine the extent of genetic control of growth traits, biomass distribution and allocation strategies, and vegetative phenology. Spacing had a significant effect on 6 of the 11 traits studied. Significant GCA variance was found for all traits except 1-year height. Individual tree narrow-sense heritability varied from 0.06 to 0.69 for root dry weight and vegetative phenology, respectively. Spacing x family interaction variance was significant for only 2 traits. Two harvest indices, based on total and above-ground dry weights, were used to assess dry matter allocation strategy and to explore potential usefulness in tree breeding. Both indices had similar heritability estimates and their genetic correlation was high (0.91), indicating that use of an index based on above ground dry weight is a good surrogate for that based on total dry weight. Genetic correlations among growth and biomass traits were generally high, while those correlations with the harvest indices were variable.

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87.
Entry, J.A., K. Cromack, Jr., R.G. Kelsey and N.E. Martin. 1991. Response of Douglas-fir to infection by Armillaria ostoyae after thinning or thinning plus fertilization. Phytopathology 81(6): 682-689.

Keywords:      thinning

                        fertilization

                        tree/stand protection

                        growth 

                        tree morphology

                        carbon allocation

                        tree/stand health

                        tree physiology

Abstract: Second-growth stands of Douglas-fir (Pseudotsuga menziesii) were thinned to a 5- x 5-m spacing (TT); additional plots were thinned and fertilized once with 360 kg of N (as urea)/ha (TF). An unthinned, unfertilized stand (UT) served as a control. Ten years after treatment, trees were inoculated with 2 isolates of A. ostoyae. Trees receiving the TF and TT treatments produced greater diameter growth, leaf area, and wood production/msuperscript 2 leaf area per year than did those under the UT treatment. Rates of infection by A. ostoyae were highest in trees that received the TF and lowest in trees that received the TT treatment. Concn of sugar, starch and cellulose in root bark tissue were highest in trees receiving the TF treatment and lowest in trees receiving TT treatment. Concn of lignin, phenolics and protein-precipitable tannins were highest in root bark from TT trees and lowest in root bark from TF trees. Biochemical parameters of root bark tissue were regressed with incidence of infection; coefficients of determination (rsuperscript 2) ranged from 0.07 (starch) to 0.57 (phenolic compounds). Ratios of the energetic costs of phenolic and of lignin degradation to the energy available from sugars (Epd:Eas and Eld:Eas) were correlated with incidence of infection (rsuperscript 2 = 0.77 and 0.70, respectively). It is concluded that thinning combined with fertilization may predispose P. menziesii trees to infection by A. ostoyae by lowering concn of defensive compounds in root bark and increasing the energy available to the fungus to degrade them.

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88. Feller, M.C. 1990. Herbicide application followed by prescribed fire to convert a brushfield into a conifer plantation in south coastal B.C.: a combination of the initial effects of two treatments. B.C. Ministry of Forests FRDA Report 146. 40 p.

Keywords:      site preparation

                        chemical preparation

                        prescribed fire

                        growth

                        tree/stand health

                        soil properties

                        stand conditions

Abstract: A field study was carried out in Pseudotsuga menziesii stands in British Columbia, Canada, to investigate the effects on vegetation of glyphosate applications in September 1987 or July 1988, followed by burning in October 1988. Results did only show slight differences between treatments.

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89.
Figueroa, P.F. 1993. Efficacy and cost of ground-applied herbicide methods for red alder control. Down to Earth 48(1): 6-10.

Keywords:      release treatments

                        chemical release

                        stand conditions

                        growth

                        tree/stand health

Abstract: The effects on red alder [Alnus rubra] mortality, diam. at breast height and height, and any phytotoxic effects to Douglas fir [Pseudotsuga menziesii] of Garlon 4 (triclopyr) at 4 lb/gallon and Chopper EC (imazapyr) at 2 lb, applied by stream line, thin line and low vol. treatments, and of Garlon 3A (triclopyr) at 3 lb, Roundup (glyphosate) at 3 lb and Arsenal (imazapyr) at 4 lb applied by cut stump treatment were evaluated in streamside buffer zones in two 6-year-old P. menziesii plantations in SW Washington. All treatments resulted in good control of A. rubra, but the most cost-effective control was achieved by the stream line application of Garlon 4, followed by low vol. basal or thin line treatments of Garlon 4 and cut stump treatment with 50% Garlon 3, 45% Roundup and 10% Arsenal. Negligible P. menziesii damage was caused by cut stump treatments, but damage occurred with basal-bark treatments although Garlon 4 generally caused less injury than Chopper EC.

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90.
Figueroa, P.F., R.C. Heald and S.R. Radosevich. 1990. Sensitivity of actively growing Douglas-fir to selected herbicide formulations. Proceedings-of-the-Western-Society-of-Weed-Science 43: 45-52.

Keywords:      release treatments

                        chemical release

                        growth

                        tree/stand health

Abstract: The results of field studies at 2 sites in Washington and California indicated that aerial spraying of 2,4-D at 4 lb/acre, triclopyr ester at 4 lb/acre or 2,4-D + triclopyr ester at 1.2 lb/acre + 0.5 lb/acre to control red alder [Alnus rubra] led to a significant reduction in Douglas fir [Pseudotsuga menziesii] growth and survival if applied during periods of active conifer growth. Herbicides applied singly at high rates caused significantly more mortality than the herbicides in combination. At both sites, trees had not fully recovered 5 and 6 years after treatment; damaged trees were at least 1 year behind untreated trees in growth.

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91.
Filip, G.M. and L.M. Ganio. 2004. Early thinning in mixed-species plantations of Douglas-fir, hemlock, and true fir affected by Armillaria root disease in Westcentral Oregon and Washington: 20 year results. Western-Journal-of-Applied-Forestry 19(1): 25-33.

Keywords:      thinning

                        precommercial thinning

                        tree/stand protection

                        growth

                        tree/stand health

Abstract: Four 10- to 20-year-old plantations were treated to determine the effects of precommercial thinning on tree growth and mortality caused by Armillaria root disease in the Cascade Range of western Oregon and Washington, USA. One plantation was Douglas-fir (Pseudotsuga menziesii) and noble fir (Abies procera), one Douglas-fir and western hemlock (Tsuga heterophylla), one Douglas-fir alone, and one Shasta red fir (Abies magnifica var. shastensis) and mountain hemlock (Tsuga mertensiana). After 20 years, differences in crop tree mortality between thinned and unthinned plots were not significant (P=0.9768). Quadratic mean diameter growth of crop trees, however, was significantly (P=0.0053) greater in thinned than in unthinned plots. Crop tree basal area/ac growth was significantly (P=0.0008) greater in thinned plots. There were no significant (P=0.6647) differences in basal area/ac growth of all trees between thinned and unthinned plots. Apparently, from a root-disease perspective, precommercial thinning does not affect incidence of crop-tree mortality after 20 years, but individual and per acre tree growth of crop trees increase significantly.

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92.
Filip, G.M. and D.J. Goheen. 1995. Precommercial thinning in Pseudotsuga, Tsuga, and Abies stands affected by armillaria root disease: 10-year results. Canadian-Journal-of-Forest-Research 25(5): 817-823.

Keywords:      thinning

                        precommercial thinning

                        tree/stand protection

                        growth

                        tree/stand health

Abstract: Four 10- to 20-year-old stands were pre-commercially thinned to determine the effects of thinning on tree growth and mortality caused by armillaria root disease (Armillaria ostoyae) in the Cascade Range of western Oregon and Washington, USA: one stand of Douglas fir (Pseudotsuga menziesii var. menziesii) and noble fir (Abies procera), one of Douglas fir and western hemlock (Tsuga heterophylla), one of Douglas fir alone, and one of Shasta red fir (Abies magnifica var. shastensis) and mountain hemlock (Tsuga mertensiana). After 10 years, differences in crop-tree mortality between thinned and unthinned plots were not significant in any of the four stands. Tree radial growth was significantly increased by thinning in 6 of 15 plots. Crop-tree basal area (per hectare) growth was significantly greater in thinned plots. Basal area (per hectare) growth of all trees was significantly greater in unthinned plots. Apparently, from a root-disease perspective, pre-commercial thinning does not affect the incidence of crop-tree mortality after 10 years, but tree growth increases significantly.

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93.
Flint, L.E. and S.W. Childs. 1987. Effect of shading, mulching, and vegetation control on Douglas-fir seedling growth and soil water supply. Forest-Ecology-and-Management 18(3): 189-203.

Keywords:      release treatments

                        chemical release

                        manual release

                        growth

                        soil properties

Abstract: Harsh environments on many harvested sites in SW Oregon necessitate site modifications for successful regeneration of Douglas fir. A 2-yr study was made with 350 seedlings to assess the effects of 12 soil-surface shading, mulching, and vegetation control techniques on seedling growth and soil temp. and moisture environments. Major effects of treatments were to lower soil surface temp., reduce soil surface evaporation, and reduce vegetative competition for soil water. These affected seedlings by adjusting the timing of seedling growth and reducing soil water loss to increase available water for seedling use. Final seedling shoot vol. and stem diam. both differed among treatments. Seedlings in treatments where competing vegetation was controlled showed significantly greater growth than seedlings in other treatments. Soil water loss in treatments where either soil surface evaporation was controlled by mulching, or where competing vegetation was controlled, was significantly less than water loss from the shaded and control treatments. Soil water loss in treatments with vegetation controlled by herbicide was significantly less than in treatments with vegetation controlled by scalping. Seedlings showed greatest growth with treatments that elicited the most efficient use of available microsite water either by reducing soil surface evaporation or vegetation competition.

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94.
Folk, R.S., S.C. Grossnickle, P. Axelrood and D. Trotter. 1999. Seed lot, nursery, and bud dormancy effects on root electrolyte leakage of Douglas-fir (Pseudotsuga menziesii) seedlings. Canadian-Journal-of-Forest-Research 29(8): 1269-1281.

Keywords:      nursery operations

                        tree physiology

                        tree/stand health

                        photosynthesis

                        growth

                        tree phenology

Abstract: The effects of seed lot, nursery culture, and seedling bud dormancy status on root electrolyte leakage (REL) of Douglas-fir (Pseudotsuga menziesii) seedlings were assessed to determine if these factors should be considered when interpreting REL for seedling quality. The relationships of REL to survival, net photosynthesis (Pn), stomatal conductance (gwv) mid-day shoot water potential ( Psi mid), root growth capacity (RGC), and relative height growth were determined for each factor in experiments in 1994-95 in nurseries in British Columbia. Nursery culture had no effect on the relationship between REL and all other measured attributes. Seed lot affected the relationship between REL and Pn, Psi mid, and survival. However, critical REL (i.e., lowest value associated with detectable root damage) and PS80 REL (i.e., level associated with an 80% probability for survival) were similar between seed lots. Bud dormancy status affected the relationship between REL and survival, RGC, and relative height growth. Control levels of REL, critical REL, and PS80 REL decreased as the number of days required for 50% terminal bud break declined. Thus, terminal bud dormancy status must be known before REL can be used to assess seedling quality. If the bud dormancy status of Douglas-fir populations is known, then critical and PS80 REL levels may be useful as indices of root damage.

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95.
Frey Klett, P., J.L. Churin, J.C. Pierrat and J. Garbaye. 1999. Dose effect in the dual inoculation of an ectomycorrhizal fungus and a mycorrhiza helper bacterium in two forest nurseries. Soil Biology and Biochemistry 31:1555-1562.

Keywords:      nursery operations

                        growth

                        carbon allocation

                        mycorrhizal response

                        soil properties

Abstract: Disinfected soil at two Douglas-fir (Pseudotsuga menziesii) bare-root forest nurseries was inoculated with three doses (8 X105, 8 X107 and 8 X109 cfu [colony forming units]/m2) of the rifampicin-resistant mycorrhiza helper bacterium Pseudomonas fluorescens strain BBc6R8 and the ectomycorrhizal fungus Laccaria bicolor strain S238N. In one of the two nurseries, two doses of fungal inoculum (50 and 100 mg/m2 dry weight (DW) mycelium entrapped in alginate beads at the constant dose of 1 litre/m2) were tested. For all bacterial treatments the density of P. fluorescens BBc6R8 in the soil, determined by dilution plating, dropped below the detection limit (10-2 cfu/g DW soil) 2 weeks after inoculation. Fifteen weeks after inoculation, the introduced bacterium was detected by enrichment only in the treatments inoculated with the highest bacterial dose. Two years after inoculation, P. fluorescens BBc6R8 was not detected in the soil of any of the bacterial treatments. Five months after inoculation and sowing, bacterial inoculation significantly increased the percentage of mycorrhizal short roots on plants inoculated with either low or high amounts of L. bicolor, in one of the nurseries. The lowest bacterial dose increased mycorrhizal colonization from 45 to 70% in plants inoculated with the low amount of fungal inoculum, and from 64 to 77% in plants inoculated with the high amount of fungal inoculum. The lowest bacterial dose increased mycorrhizal colonization more than the highest bacterial dose. The same L. bicolor mycorrhizal index (70%) was obtained with 50 mg/m2 DW mycelium plus the bacterium than with twice this fungal dose and no bacterium (64%). Two years after inoculation, the height of the mycorrhizal Douglas-firs in the other nursery was significantly increased by the lowest bacterial dose (from 40.7 to 42.6 cm). It was indicated that co-inoculating a helper bacterium together with an ectomycorrhizal fungus is an efficient way to optimize controlled mycorrhization techniques for the production of high-quality Douglas-fir planting stocks. It was confirmed that BBc6R8 acts at a low population density (less than 10-2 cfu/g soil), this contrasts with most PGPR [plant growth promoting rhizobacteria?] effects where the minimal inoculation dose of 105 cfu/g soil is required to obtain the beneficial effect.

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96.
Fu, Y., A.D. Yanchuk and G. Namkoong. 1999. Spatial patterns of tree height variations in a series of Douglas-fir progeny trials: implications for genetic testing. Canadian-Journal-of-Forest-Research 29(6): 714-723.

Keywords:      genetic tree improvement

                        growth

Abstract: Conventional statistics and geostatistical techniques were used to examine spatial variation patterns of tree heights at ages 6-12 years in a series of Douglas fir (Pseudotsuga menziesii) progeny trials conducted on 66 test sites over southern coastal British Columbia. Large variations in tree height were observed over the years within and among the 66 test sites. The estimated proportions of the within-site variance explained by family, row, column, patchiness and within-plot were on average 11, 7, 5, 12 and 47%, respectively, plus 7% due to unknown factors, and the applied blocking removed about 5% of the within-site variance. Significant gradients in row and column directions were observed in more than 44 test sites, and the estimated slopes ranged in average from 0.33 to 1.52 cm/plot. Patch sizes varied greatly over the test sites and ranged in average from 5.21 to 6.47 plots, indicating that the average patch size for these trials was 18 m across. Temporal variations were large for family variance but not much for those variance proportions explained by row, column and patchiness. More gradients and larger patch sizes were found with older trees. The implications of these results are discussed in relation to forest genetic testing.

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97.
Gagnon, J., C.G. Langlois, D. Bouchard, F.l. Tacon and F. Le Tacon. 1995. Growth and ectomycorrhizal formation of container-grown Douglas-fir seedlings inoculated with Laccaria bicolor under four levels of nitrogen fertilization. Canadian Journal of Forest Research 25:1953-1961.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        carbon allocation

                        tree physiology

                        tree morphology

                        mycorrhizal response

                        soil properties

Abstract: Container-grown Douglas fir (Pseudotsuga menziesii) seedlings were inoculated at the time of sowing with a Laccaria bicolor mycelial suspension produced in a fermentor. They were grown in a peat moss-vermiculite substrate under four levels of N fertilization (7.2, 14.4, 21.6 and 28.7 mg/seedling per season (N1, N2, N3 and N4, respectively)) to determine the N level suitable for both ectomycorrhizal development and seedling growth. After 18 weeks in the greenhouse, seedlings inoculated with L. bicolor had 44%, 32%, 44% and 5% of their short roots mycorrhizal when fertilized with N1, N2, N3 and N4, respectively. Only when they were fertilized with N4 did the L. bicolor seedlings have significantly greater shoot height than the controls. For the other growth parameters, they were not significantly different from control seedlings for any of the N levels. After 18 weeks, regardless of the level of N, seedlings inoculated with L. bicolor had significantly lower N concentrations (%) and contents (mg/seedling) than the uninoculated ones. Consequently, for the same production of biomass, the mycorrhizal seedlings had taken up less N than the nonmycorrhizal ones. The efficiency of applied N, expressed in terms of produced biomass, decreased when the N fertilization increased; mycorrhizal and nonmycorrhizal seedlings did not tend to be different. The efficiency of the absorbed N also decrease with the level of applied N, but less rapidly, and tended to be greater for the mycorrhizal seedlings than for the nonmycorrhizal ones. Therefore, the mycorrhizal infection improved the utilization of the absorbed N. N3 was the best of the four N levels used, since it was the only one that maximized both the ectomycorrhizal formation and the growth of the seedlings. In other words, a total seedling N concentration of 1.6% and a substrate fertility of 52 p.p.m. N are appropriate to optimize both the ectomycorrhizal development and the growth of Douglas fir seedlings.

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98.
Gardner, E.R. 1990. Fertilization and thinning effects on a Douglas-fir ecosystem at Shawnigan Lake: 15-year growth response. Canadian-Forest-Service, Pacific and Yukon Region Information-Report BC-X-319. ix + 42 p.

Keywords:      fertilization

                        thinning

                        growth

                        yield

                        tree morphology

                        tree/stand health

Abstract: Responses after 15 yr to 3 rates of nitrogen (urea), applied at 0, 224 or 448 kg N/ha to a 24-yr-old Douglas fir (Pseudotsuga menziesii) stand in the very dry maritime region of British Columbia, were analysed on the basis of per hectare, individual tree, crop tree and tree size class. Thinned and unthinned plots were measured.

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99.
Gertner, G.Z. 1984. Localizing a diameter increment model with a sequential Bayesian procedure. Forest-Science 30(4): 851-864.

Keywords:      fertilization

                        growth

Abstract: A procedure is described for modifying a non-linear model taken from a regional forest growth projection system for use in a smaller subregion. Diameter growth monitored in the subregion of interest is used to adjust the parameters. The amount of adjustment required depends on the precision of the growth estimates from the regional model and of the estimates based on the local sample. More weight is given to the local estimates when their precision is relatively high in comparison with the regional estimates. An example is given of modifying a model developed for the Western Oregon Region for a Douglas fir stand in NW Oregon. In another example the procedure is used to adjust for the effects on diam. increment of fertilizing with urea.

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100.
Gessel, S.P. and W.A. Atkinson. 1984. Use of fertilizers in sustained productivity of Douglas-fir forests. In Forest soils and treatment impacts: Proceedings, Sixth North American Forest Soils Conference, Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN, June 1983. pp. 67-87.

Keywords:      fertilization

                        growth

                        economics

Abstract: A review is given of studies leading to the establishment of nitrogen deficiency as a factor reducing growth and the development of N fertilization programmes. Data from several long-term fertilizer trials in Washington and Oregon support the conclusion that N deficiency is frequently a controlling factor in the growth of Douglas fir and that additions of N can result in long-term growth increases. The economics of fertilization and the continued availability of nitrogen fertilizers are discussed.

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101.
Gessel, S.P., R.E. Miller and D.W. Cole. 1990. Relative importance of water and nutrients on the growth of coast Douglas fir in the Pacific Northwest. Forest-Ecology-and-Management 30(1-4): 327-340.

Keywords:      fertilization

                        growth

                        soil properties

Abstract: The Douglas-fir region in northwestern North America is characterized by abundant moisture supply during winter, extended dry periods during the growing season and significant differences in water availability. Many soils have low fertility and indigenous tree species respond to nitrogen fertilization, especially Douglas fir (Pseudotsuga menziesii). Although irrigation of commercial forests in this region is currently impractical, questions arising about the relative importance of water and nutrients were examined using long-term growth data from three studies. At Pack Forest (Washington), fertilization without irrigation doubled growth rates, and no positive growth responses were measured from irrigation. Short-term (5 yr) irrigation with sewage effluent containing many nutrients resulted in a six-fold increase in biomass production for poplar and three-fold for Douglas fir as compared to irrigation with equal volumes of river water. Volume growth in 12- to 65-yr-old stands in southwestern Oregon was increased by fertilization at about 70% of the locations; annual gain averaged 2.73 msuperscript 3/ha for 5-12 yr. Response was not related to annual precipitation, which ranged from 81 to 279 cm, nor other moisture-related variables. Absolute and relative volume response showed highest correlation with soil carbon : nitrogen ratio. Compared with nutrition, moisture does not seem to be a major limiting factor for growth in the Douglas fir region of the Pacific Northwest.

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102.
Gessel, S.P., E.C. Steinbrenner and R.E. Miller. 1981. Response of Northwest forests to elements other than nitrogen. In Proceedings: Forest Fertilization Conference, University of Washington, Seattle, Washington, USA. Eds. S.P. Gessel, R.M. Kenady and W.A. Atkinson. pp. 140-149.

Keywords:      fertilization

                        growth

                        economics

Abstract: This paper reviews the development of forest tree nutrition research in the Northwest. Field observations, foliar analysis, and greenhouse cultures using both solution and forest soil as media established deficiency symptoms and levels for major and minor elements. Field experimentation with the entire range of essential elements has failed to demonstrate widespread deficiencies of elements other than nitrogen. Certain test areas have shown somewhat better response to combinations of elements; but because of the limitations of experimental design and field variation, the response does not generally have a high statistical significance. In some cases of apparent response, application of fertilizer materials other than nitrogen does not appear to be economic. There is sufficient evidence of response to other elements to suggest that much work needs to be done. Increased utilization of forest materials, shorter rotation, and greater yields with nitrogen fertilization all point to the fact that many of the Northwest forest areas could have future elemental deficiencies, other than nitrogen.

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103.
Gourley, M., M. Vomocil and M. Newton. 1990. Forest weeding reduces the effect of deer-browsing on Douglas fir. Forest-Ecology-and-Management 36(2-4): 177-185.

Keywords:      release treatments

                        chemical release

                        tree/stand protection

                        growth

                        tree/stand health

Abstract: In January and February 1981, three-year-old bare-root Douglas fir (Pseudotsuga menziesii) transplants were established in four clear-felled locations in the Oregon Coast Range where browsing by black tail deer (Odocoileus hemionus columbiana) was expected. Protection was provided against browsing by 5 physical (rigid protection tube 7.5x75 cm; protective netting, paper budcaps; leather guard 20x5 cm; and 'Remae' budcaps) and one chemical ('Deer Away') treatment, each of which was tested with and without complete wood control with glyphosate. After five years, none of the protective treatments provided any growth advantages; some even caused growth losses. In contrast, weed control, with or without additional protective measures, consistently improved growth. By the 5th year, weeded trees averaged twice the biomass of unweeded trees, regardless of browsing. Average tree size was largest in the treatment with no weed competition and with no barriers to prevent browsing. Advantages of weeding were greatest on the poorest site. Weed control, in conjunction with the large size of transplants, appeared to prevent most loss due to damage from moderate deer-browsing.

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104.
Graff, J.E., Jr., R.K. Hermann and J.B. Zaerr. 1999a. Dry matter and nitrogen allocation in western redcedar, western hemlock, and Douglas fir seedlings grown in low- and high-N soils. Annals-of-Forest-Science 56(7): 529-538.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

Abstract: Seedlings of western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Douglas fir (Pseudotsuga menziesii) were transplanted into each of 48 pots with soils of low or high levels of available NO3- (and total N) and assigned to one of four treatments: unamended control; amendment with 60 mg kg-1 (NH4)2SO4; amendment with 15 mg kg-1 of the nitrification inhibitor dicyandiamide (DCD) or amendment with both (NH4)2SO4 and DCD. Dry weight and N content increments of seedling tissues were determined after 8 weeks. Seedlings grown on the low-N soil accumulated 65 % of the dry matter and 40 % of the N accumulated by seedlings grown on the high-N soil. Retranslocation of N from year-old foliage and the stem/branch components of western red cedar and Douglas fir, but not western hemlock, was an important source of N for current-year foliage and roots of low-N-grown seedlings. Western hemlock achieved the greatest relative dry-matter increment (Loge(DMfinal) - Loge(DMinitial); RDMI) and relative N increment (Loge(Nfinal) - Loge(Ninitial); RNI) in each soil and accumulated 35 % more N from the low-N and 10 % more N from the high-N soils than the other species. The RDMI of western red cedar was intermediate between that of western hemlock and Douglas fir, whereas its RNI on each of the soils was lowest. The results suggest that western hemlock is more efficient than western red cedar or Douglas fir in acquiring inorganic N, especially from low-N soils.

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105.
Green, R.N. and R.E. Carter. 1993. Boron and magnesium fertilization of a coastal Douglas-fir plantation. Western-Journal-of-Applied-Forestry 8(2): 48-53.

Keywords:      fertilization

                        growth

                        tree/stand health

                        tree physiology

Abstract: A study was made of the role of boron and magnesium nutrition in the occurrence of severe growth distortion symptoms in Douglas-fir (Pseudotsuga menziesii) in the Skwawka River valley of south coastal British Columbia. Four fertilizer treatments, including boron (2.25 kg/ha B), magnesium (42 kg/ha Mg), boron plus magnesium, and a control, were applied in conjunction with planting on a site believed to be deficient in these nutrients. After 5 growing seasons, only treatments containing boron (B and B + Mg) showed improved height growth compared to controls. The incidence of leader dieback, swollen leading shoots, and foliage distortion was significantly related to treatment, with virtually no occurrence in plots treated with boron. Seedling uptake of applied boron was high, with foliar concentrations of 45 p.p.m. found after the second growing season. Foliar B levels declined to 13-15 p.p.m. after 5 growing seasons. No significant increase in foliar magnesium levels was detected for either of the magnesium treatments. The reduction in the incidence of leader dieback, and shoot and foliar symptoms, in seedlings treated with B indicate that these symptoms were the result of boron deficiencies. This is the first study to verify boron deficiency in coastal Douglas fir through fertilizer trials.

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106.
Greene, S.E. and W.H. Emmingham. 1986. Early lessons from commercial thinning in a 30-year-old Sitka spruce-western hemlock forest. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Note PNW-RN-448. 14 p.

Keywords:      thinning

                        commercial thinning

                        growth

                        tree/stand health

                        tree morphology

Abstract: Three commercial thinning treatments were applied to a 30-yr-old stand of Picea sitchensis and Tsuga heterophylla with Pseudotsuga menziesii that had been precommercially thinned at 15 yr old on the Oregon coast. Data were collected to determine the effects of thinning on diam. and ht. growth, the amount of damage and subsequent decay in remaining trees and relations between leaf area and volume production.

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107.
Grier, C.C., K.H. Lee and R.M. Archibald. 1984. Effect of urea fertilization on allometric relations in young Douglas-fir trees. Canadian-Journal-of-Forest-Research 14(6): 900-904.

Keywords:      fertilization

                        growth

                        carbon allocation

                        tree morphology

Abstract: Twenty three yr old trees growing on a class III site in Washington State were fertilized with 225 kg/ha N in March 1980. Trees were measured before fertilizing and after 1980-83 growing seasons and destructively sampled after 2 growing seasons (in Nov.-Dec. 1981 and Jan. 1982). Logarithmic regression equations using stem diam. to predict tree biomass components were not significantly (p = 0.05) different between fertilized and control trees for total foliage, total branch, dead branch, stembark, or stemwood. New foliage and new twig components, however, were higher in fertilized trees than in control trees. Analysis of data from this and earlier studies suggests that fertilizing will increase leaf biomass per tree relative to control trees on sites having low nitrogen availability; however, this response will decrease with increasing nitrogen availability. Regression equations based on regional analysis of unfertilized trees yield estimates of foliage biomass for average trees on average sites. If N fertilizing brings the site above average in terms of nitrogen availability then these regression equations will underestimate foliage biomass. However, on sites that are initially very nitrogen deficient, N fertilizing will bring the site closer to average in terms of nitrogen availability, resulting in more accurate predictions of foliage biomass for fertilized stands than for control stands.

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108.
Haase, D.L., J.H. Batdorff and R. Rose. 1993. Effect of root form on 10-year survival and growth of planted Douglas-fir trees. Tree-Planters' Notes 44(2): 53-57.

Keywords:      planting operations

                        growth

                        tree/stand health

Abstract: Douglas fir seedlings (Pseudotsuga menziesii) were planted with three root-form treatments including C-roots ('correctly' planted controls), L-roots, and J-roots. After 10 years, there were no significant differences in outplanting performance between the three root-form treatments on a good site in western Oregon. The results are in agreement with those of other studies, which suggests that when no other confounding planting errors are present, deformed root systems play a less dramatic role in subsequent field performance than is generally thought. These results in no way imply that poor planting is acceptable.

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109.
Haase, D.L. and R. Rose. 1993. Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-fir seedlings of varying root volumes. Forest-Science 39(2): 275-294.

Keywords:      nursery operations

                        tree/stand protection

                        growth

                        tree morphology

Abstract: Transplant stock was induced by applying a range of soil water contents (6, 12, 18 or 24%) to unstored and cold-stored 2-yr-old (2 + 0) bareroot Douglas fir (Pseudotsuga menziesii) seedlings graded by root volume. Moisture stress had the greatest influence on morphological characteristics that express transplant shock. Seedling terminal shoot growth, stem diameter growth, and needle length increased with increased soil moisture content. In addition, number of needles per centimeter on the terminal shoot greatly increased with increasing drought stress. Under high drought stress, seedlings with relatively high root volumes tended to exhibit reduced early growth, but later showed significantly increased overall growth regardless of soil water content. In every case, seedlings grown in the driest soil had the lowest dry weight components. Similarly, seedlings with the smallest initial root volumes had the lowest dry weights, and those with the largest root volumes had the greatest dry weights. The results indicate that drought stress is a cause of transplant shock, and that increased seedling root volume may enable seedlings to avoid shock following outplanting to a specific site.

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110.
Haase, D.L. and R. Rose. 1994. Effects of soil water content and initial root volume on the nutrient status of 2+0 Douglas-fir seedlings. New-Forests 8(3): 265-277.

Keywords:      nursery operations

                        tree/stand protection

                        tree physiology

                        growth

                        tree morphology

Abstract: Two-year-old bareroot Douglas fir (Pseudotsuga menziesii) seedlings from a NW Oregon provenance were graded on the basis of four root-volume categories - 5 to 8, 9 to 10, 11 to 13, and 14 to 20 cmsuperscript 3 - and transplanted into pots and subjected to one of four moisture-stress treatments (6, 12, 18, and 24% soil water content) for 16 weeks. Macronutrient concentrations and contents of both old (i.e. nursery-grown) and new (i.e. grown during moisture stress treatment) foliar tissue were determined. A reduction in soil water content resulted in high concn of phosphorus, potassium, and particularly nitrogen in both old and new foliar tissue. This was attributed to reduced growth, translocation, metabolic activity, and nutrient requirement in response to moisture stress. Seedlings with relatively greater root volumes exhibited higher nutrient concn and contents, as well as increased growth. Thus, increased total root biomass per unit of soil area with increasing seedling root volume may have resulted in greater nutrient use, supply, uptake, and storage. It is suggested that relations between initial root volume and water stress can be applied to nursery cultural practices in order to increase seedling adaptation to a specific stress.

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111.
Haase, D.L., J. Trobaugh and R. Rose. 1999. Douglas-fir container stock grown with fertilizer-amended media: some preliminary results. Rocky Mountain Research Station, USDA Forest Service National Proceedings: Forest and Conservation Nursery Associations 1999, 2000, and 2001. RMRS P-24. 31-32 pp.

Keywords:      nursery operations

                        nursery fertilization

                        growth

                        tree physiology

                        tree/stand health

Abstract: This paper presents the initial results of a study conducted in a nursery in Oregon, USA, to quantify the response of container grown Douglas-fir (Pseudotsuga menziesii) seedlings to various fertilizer treatments (Simplot's 13-13-13 and 17-5-11, and Scotts Company's 18-5-12 and 15-9-10) in terms of height, stem diameter and foliar nutrient content.


112.
Hahn, P.F. and A.J. Smith. 1983. Douglas-fir planting stock performance comparison after the third growing season. Tree-Planters' Notes 34(1): 33-39.

Keywords:      nursery operations

                        planting operations

                        growth

                        tree/stand health

Abstract: Three types of containerized (40, 75 or 125 cmsuperscript 3 containers) and bare rooted (2+1, 3+0 and plug-1 stock) seedlings were planted out in Oregon in Feb. 1979 on N. and S. facing slopes, clear felled in 1978. In general, containerized seedlings showed superior survival rates and greater height growth - particularly on the harsh S. slope, and lower reforestation costs. The 75-cmsuperscript 3 containerized seedlings are recommended, except for N. facing and wet coastal areas, where brush competition can be severe shortly after planting. In such areas, taller bare-rooted seedlings performed better.

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113.
Hall, T.H., R.V. Quenet, C.R. Layton and R.J. Robertson. 1980. Fertilization and thinning effects on a Douglas-fir ecosystem at Shawnigan Lake: 6 year growth response. Pacific-Forest-Research-Centre, Canadian Forestry Service Information-Report BC-X-202. 31 p.

Keywords:      fertilization

                        thinning

                        growth

Abstract: Further results are given for this stand in British Columbia at 30 yr old [see FA 43, 1945]. Gains in gross vol. increment (over control at 24 yr old) for the 200 initially largest trees/ha were 20% for heavy thinning alone, 51% for heavy fertilizer (urea) application alone and 139% for heavy thinning plus heavy fertilizer application. Adjustments by covariance analysis for differences in intitial stocking and tree size distributions gave values of 47, 76 and 139% respectively.

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114.
Hansen, E.M., J.K. Stone, B.R. Capitano, P. Rosso, W. Sutton, L. Winton, A. Kanaskie and M.G. McWilliams. 2000. Incidence and impact of Swiss needle cast in forest plantations of Douglas-fir in coastal Oregon. Plant-Disease 84(7): 773-778.

Keywords:      tree/stand protection

                        growth

                        tree/stand health

Abstract: An epidemic of Swiss needle cast, caused by the ascomycete Phaeocryptopus gaeumannii, is causing defoliation and growth reductions in Douglas-fir forest plantations along the Oregon Coast. The area of symptomatic plantations has been monitored annually since 1996 by aerial survey; in spring 1999, 119,500 ha were affected. Pathogen and symptom development have also been monitored on nine permanent plots in stands of differing disease severity. Infection levels and symptom severity are greatest in low elevation plantations close to the coast. In areas of severe disease, trees retain only current year needles. Defoliation is proportional to the number of stomata occluded by pseudothecia of the fungus, with needles being shed when about 50% of stomata are occupied, regardless of needle age. Fungus sporulation and premature needle abscission are greatest on the upper branches of trees. Annual application of fungicides increases needle retention significantly. Tree height and diameter growth and total tree volume are reduced by disease, and tree volume is significantly correlated with needle retention on our plot trees. The epidemic continues to be most severe in Douglas-fir plantations established on sites where Sitka spruce and western hemlock or red alder predominated in earlier times.

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115.
Harper, P.A. and A.S. Harestad. 1986. Vole damage to coniferous trees on Texada Island. Forestry-Chronicle 62(5): 429-432.

Keywords:      thinning

                        precommercial thinning

                        tree/stand protection

                        tree/stand health

                        growth

Abstract: Microtus townsendii injured trees by removal of bark and cambium from stems, branches and roots of Douglas fir, western hemlock and, rarely, Pinus monticola on Texada Island, British Columbia. Damage occurred more frequently in precommercially thinned stands <40 yr old than in unspaced stands. Trees with d.b.h. <less or =>19 cm were damaged by voles, but there was no selection by diam. or age class. No trees of ht. >16 m were damaged. For trees <16 m, damage increased as ht. decreased. There were n.s.d. in growth rates of trees damaged by voles when comparing the 2-yr av. before spacing and vole damage with the av. after these events. Stands should continue to be monitored to evaluate long-term effects of vole damage. On the basis of these results, control of voles is not recommended.

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116.
Harrington, T.B. and J.C. Tappeiner, II. 1997. Growth responses of young Douglas-fir and tanoak 11 years after various levels of hardwood removal and understory suppression in southwestern Oregon, USA. Forest-Ecology-and-Management 96(1/2): 1-11.

Keywords:      release treatments

                        manual release

                        growth

                        tree/stand health

Abstract: Douglas fir (Pseudotsuga menziesii) was planted as 2-yr-old bare rooted seedlings on 2 sites in SW Oregon cleared of old-growth Douglas fir and understorey tanoak (Lithocarpus densiflorus) in 1980, and broadcast burned in 1981. Planting was done in 1981 at one site and in 1982 at the second site. Height, diameter, and crown width of the young Douglas fir and sprout-origin tanoak were measured 1-11 years after reducing the density of the tanoak stand (in 1983, at 2 yr old) to 0, 25, 50 and 100% of its initial cover. On some of the experimental plots suppression of understorey vegetation was also carried out. Tanoak cover developed linearly with time, with steepness of the growth trajectory increasing at a diminishing rate with increasing percentage of initial tanoak cover. Fifth-year cover of understorey vegetation declined linearly with increasing percentage of initial tanoak cover. Survival of Douglas fir (96-100%) differed little among initial abundances of tanoak, while growth trajectories for its size became increasingly exponential with decreasing percentage of initial tanoak cover. Eleventh-year heights of Douglas fir were similar for 0, 25 and 50% of initial tanoak cover; however, diameter increased linearly with decreasing percentage of initial tanoak cover, and the slope of the relationship steepened with understorey suppression. The results indicate that young stands exhibiting a wide range of stand compositions and productivities can be established by early manipulations of tanoak and understorey abundance. Complete removal of tanoak plus understorey suppression are necessary to maximize Douglas fir growth, while productive, mixed stands can be achieved by removing 50% or more of tanoak cover.

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117.
Harrington, T.B., J.C. Tappeiner, II and T.F. Hughes. 1991. Predicting average growth and size distributions of Douglas-fir saplings competing with sprout clumps of tanoak or Pacific madrone. New-Forests 5(2): 109-130.

Keywords:      release treatments

                        manual release

                        growth

                        stand conditions

Abstract: Average growth and size distributions of 3- to 6-year-old (in 1983) Douglas fir (Pseudotsuga menziesii) saplings in three plantations in SW Oregon were studied for 7 years (1983-1989) after thinning of associated sprout clumps of tanoak (Lithocarpus densiflorus) or Pacific madrone (Arbutus menziesii); in some cases shrubs and herbs were also suppressed. Biologically based nonlinear equations explained 66, 90, and 53% of variation in average annual increment of Douglas fir height, diameter-squared, and crown cover, respectively. Equations for annual increment of crown cover of broadleaved and understorey vegetation explained only 10 to 12% of the variation, because these parameters exhibited a high degree of variability. Model simulations demonstrated that, for the same initial levels of cover, tanoak had faster rates of crown cover growth than madrone and also caused greater limitations in Douglas fir growth. Suppression of shrubs and herbs increased growth of Douglas fir only when broadleaved species were absent. Weibull functions adequately described size distributions for Douglas fir in 92% of individual-tree data sets. Regression functions of broadleaved crown cover and average Douglas fir size explained 51, 93, and 24% of variation in the Weibull A, B, and C parameters, respectively. Model simulations with predicted Weibull parameters demonstrated that broadleaved competition caused a positive skewing in size distributions for height and stem diameter of Douglas fir.

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118.
Harrington, T.B., R.G. Wagner, S.R. Radosevich and J.D. Walstad. 1995. Interspecific competition and herbicide injury influence 10-year responses of coastal Douglas-fir and associated vegetation to release treatments. Forest-Ecology-and-Management 76(1/3): 55-67.

Keywords:      release treatments

                        chemical release

                        manual release

                        growth

                        tree/stand health

                        tree physiology

                        stand conditions

Abstract: Responses of competing vegetation and planted Douglas fir (Pseudotsuga menziesii var. menziesii) were studied for 10 years after six herbicide and manual release treatments in the Washington and Oregon Coast Ranges. Studies were installed in six 2- or 3-yr-old plantations, with Douglas fir densities of 988 to 1482 plants/ha at time of planting and 721 to 1282/ha 2 to 3 years late. Research objectives were to quantify regional, long-term responses of vegetation (Douglas fir and non-coniferous species) to various levels of competition, light and soil water availability, and intensity versus importance of factors influencing Douglas fir growth. Three treatments reduced shrub cover relative to the untreated check: triclopyr in year 1, glyphosate in years 1-5, and repeated control (via several herbicide applications) in years 1-10. Reductions in woody cover from glyphosate stimulated increases in herb cover in years 3 and 5, while repeated control reduced herb cover in years 1, 2 and 5. Through year 10, Douglas fir survival (86-99%) varied little among treatments. Visual symptoms of herbicide injury to Douglas fir from triclopyr (45% of trees) and glyphosate (17% of trees) were associated with 0.1-0.2 m reductions in first-year height. After adjusting for tree size, Douglas fir growth in stem basal area 2 years after triclopyr was less than that of the untreated check, suggesting prolonged effects of herbicide injury. Because it sustained low levels of interspecific competition, caused minimal tree injury, and prevented overtopping cover from red alder (Alnus rubra), repeated control was the only treatment in which Douglas fir size (9.8 m height and 21 cm basal diameter in year 10) significantly exceeded (P<less or =>0.02) that of the untreated check (7.8 m height and 12 cm diameter).

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119.
Harrison, R.B., E.C. Turnblom, C.L. Henry, P. Leonard, R. King and R. Gonyea. 2002. Response of three young Douglas-fir plantations to forest fertilization with low rates of municipal biosolids. Journal-of-Sustainable-Forestry 14(2/3): 21-30.

Keywords:      fertilization

                        growth

                        tree/stand health

Abstract: Growth responses were monitored in three Pseudotsuga menziesii stands (Units 2, 11 and 13) in Washington, USA, following single low applications (17-19 t/ha) of municipal biosolids amendment. At the last measurement, in 1995, there were a total of 162 vs. 137 live trees (per 0.121 ha of 3 plots) in unit 2, 94 vs. 137 in unit 11, and 100 vs. 110 in unit 13 in control vs. biosolids-treated plots, respectively. The response ranged from 0.4 to 2.2 cm for average diameter at breast height, and -0.03 to 0.64 m for average total height. The small negative response could be due to mortality of trees or small errors in height measurements. The response in per ha values ranged from 0.8-5.2 m2/ha for basal area, 9-39 m3/ha for volume, and 3965-16 107 kg/ha for dry weight.

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120.
Heath, L.S. and H.N. Chappell. 1989. Growth response to fertilization in young Douglas-fir stands. Western-Journal-of-Applied-Forestry 4(4): 116-119.

Keywords:      fertilization

                        thinning

                        growth

Abstract: Response surface methodology was used to estimate 6-yr vol. growth response to 1 application of 200 lb N/acre in unthinned and thinned Douglas fir (Pseudotsuga menziesii) stands of b.h. age <less or =>25 yr in W. Washington and W. Oregon. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as b.a. increased in both unthinned and thinned stands. Response varied little over site index in regions of low b.a., decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high b.a. region.

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121.
Hedin, I.B. 1994. Mechanical site preparation on salal-dominated sites: five-year results. Forest-Engineering-Research-Institute-of-Canada

Keywords:      site preparation

                        mechanical preparation

                        growth

                        stand conditions

Abstract: Trials began in 1987 on sites on Vancouver Island where salal (Gaultheria shallon) is a competitor to Douglas fir [Pseudotsuga menziesii]. Three equipment types were tested: the Mitsui Miike (an excavator-mounted rock grinding attachment), the TTS Delta disc trencher and an excavator with a ripper tooth and live thumb. All three mechanical site preparation treatments were equally effective at reducing the coverage of salal and other competing vegetation and improving Douglas fir growth performance. On sites where the disc trencher can operate, with gentle slopes and light to moderate slash, it is most cost effective because of greater productivity.

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122.
Heilman, P. 1983. Effects of surface treatment and interplanting of shrub alder on rowth of Douglas-fir on coal spoils. Journal-of-Environmental-Quality 12(1): 109-113.

Keywords:      planting operations

                        site preparation

                        mechanical preparation

                        growth

                        tree physiology

                        soil properties

                        tree/stand health

Abstract: Annual growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) planted on topsoiled spoils at a coal mine near Centralia, Wash., was monitored for the first 6 y after planting. Treatments were contour bedding, contour bedding plus interplanted Sitka alder (Alnus sinuata (Reg.) Rydb.), and unbedded control. The bedding significantly increased growth of Douglas-fir in all 5 y of the study. Total height growth after 5 y was 35% greater than control on the bedding only plots, and 43% greater on the bedding plus Sitka alder plots. Height growth of Douglas-fir in the mixed stand was significantly greater during the 2nd and 3rd y of the study, but after 5 yr, no significant difference was evident in total height between the mixed and pure Douglas-fir plots. Concentration of N in Douglas-fir foliage was significantly increased by bedding in the fifth but not in the fourth year. Interplanting with Sitka alder had no significant effect on N in Douglas-fir foliage. The top 0.3 m of soil in the ridged portion of the bedded area contained significantly less moisture over a summer than did the top 0.3 m of the unbedded soil. At deeper depths, however, soil moisture was not significantly affected by bedding. Wind damage caused by a severe storm that occurred after 5 y was very much greater on the unbedded plots (49% wind-thrown vs. 9 to 15% wind-thrown on the bedded plots) despite the smaller size of the trees on unbedded plots.

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123.
Helgerson, O.T. 1985. Survival and growth of planted Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and ponderosa pine (Pinus ponderosa Dougl. ex Laws.) on a hot, dry site in southwest Oregon. Tree-Planters' Notes 36(4): 3-6.

Keywords:      nursery operations

                        planting operations

                        tree/stand health

                        growth

Abstract: One-yr-old containerized seedlings and 2-yr-old bare rooted seedlings of both species were planted in Feb. 1982 on a W.-facing 35% slope on Tin Pan Peak. The site receives <760 mm of precipitation annually. Weeds were controlled with herbicides applied before and after planting. Survival after 2 yr averaged 94% for all stock types; survival of bare rooted seedlings (98-99%) was significantly better than that of containerized seedlings (88-92%). Relative vol. growth was greater for pine than Douglas fir. After 2 yr, the 2+0 bare rooted pines were significantly larger than the 2+0 Douglas firs, despite a smaller starting size.

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124.
Helgerson, O.T. 1990a. Effects of alternate types of microsite shade on survival of planted Douglas-fir in southwest Oregon. New-Forests 3(4): 327-332.

Keywords:      planting operations

                        tree/stand protection

                        tree/stand health

                        growth

Abstract: Five-yr survival of 2+0 bare root Douglas fir (Pseudotsuga menziesii) seedlings was increased by 3 types of shading: cardboard shadecards placed S. or E. of seedlings; and bottomless styrofoam cups inverted around seedling base, on 2 S.-facing sites. On the drier site, seedlings survived well without shading (89% unshaded, 98% shaded), but on the wetter site, where seedlings were more stressed, shading was more beneficial (62% unshaded, 89% shaded). Shading did not affect growth. Seedlings grew more in 5 yr on the drier than the wetter site, possibly because of better handling and planting practices, less browsing by deer, and better weed control.

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125.
Helgerson, O.T. 1990b. Response of underplanted Douglas-fir to herbicide injection of sclerophyll hardwoods in southwest Oregon. Western-Journal-of-Applied-Forestry 5(3): 86-89.

Keywords:      nursery operations

                        release treatments

                        chemical release

                        stand conditions

                        tree physiology

                        tree/stand health

                        growth

Abstract: Low-value broadleaf sclerophyll forests in SW Oregon, typically composed of tanoak (Lithocarpus densiflorus), Pacific madrone (Arbutus menziesii) and chinkapin (Castanopsis chrysophylla), may be converted to commercially valuable Douglas fir (Pseudotsuga menziesii) by underplanting. Results are given of studies of container-grown plug and nursery-grown bareroot fir seedlings planted out in March 1983 on plots in which all broadleaf stems had been previously (September 1981) injected with triclopyr amine. Although 60% broadleaf cover was killed by injection, 7 years later ground cover was significantly greater on these treated plots because of sprouting. Seedlings planted beneath treated broadleaf trees experienced greater daytime, but less predawn, moisture stress; plugs survived better than bareroots; and survival of seedlings on treated plots was not significantly better until 2 years after planting. Herbicide injection also resulted in increased height, diameter and volume growth rates of Douglas fir seedlings, and is recommended for the establishment of a conifer stand.

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126.
Helgerson, O.T., D.H. McNabb and S.D. Hobbs. 1991. Survival and growth of Douglas-fir seedlings after prescribed burning of a brushfield in southwest Oregon. Western-Journal-of-Applied-Forestry 6(3): 55-59.

Keywords:      site preparation

                        prescribed fire

                        tree/stand health

                        growth

Abstract: Five years after planting, survival of 2-0 bare root Douglas fir (Pseudotsuga menziesii) seedlings was high on both burned and unburned plots (89 and 87%, respectively), but seedling stem height, diameter, and volume were greater in burned than in unburned plots.

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127.
Helgerson, O.T., S.D. Tesch, S.D. Hobbs and D.H. McNabb. 1989. Survival and growth of ponderosa pine and Douglas-fir stocktypes on a dry low-elevation site in southwest Oregon. Western-Journal-of-Applied-Forestry 4(4): 124-128.

Keywords:      nursery operations

                        planting operations

                        growth

                        tree/stand health

Abstract: Two stocktypes (1+0 container-grown plugs and 2+0 nursery-grown bareroots) of ponderosa pine (Pinus ponderosa) and of Douglas fir (Pseudotsuga menziesii) were planted on a hot, droughty, low-altitude site near Medford, Oregon, which had burned in 1981. The main objective was to assess the potential for reforesting this type of site. After 5 growing seasons, bare rooted stock survived (98%) significantly better than plugs (89%); survival did not differ significantly by species. Douglas fir was taller than pine, pine was larger in diam., and the 2 species had approximately equal stem volumes. Bare rooted stock was consistently larger than plugs. Results show that these species and stocktypes can provide good reforestation after 5 yr on this type of site when seedlings are of good quality, are planted properly, and are given good weed control.

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128.
Helgerson, O.T., S.D. Tesch, S.D. Hobbs and D.H. McNabb. 1992. Effects of stocktype, shading, and species on reforestation of a droughty site in southwest Oregon. Northwest-Science 66(2): 57-61.

Keywords:      nursery operations

                        planting operations

                        tree/stand protection

                        tree/stand health

                        growth

Abstract: On hot, dry sites, shading may differentially increase survival of planted Douglas fir (Pseudotsuga menziesii) according to seedling size, and Douglas fir may differ from ponderosa pine (Pinus ponderosa) in early survival and growth. The survival and growth of Douglas fir seedlings (1+0 container-grown plugs and 2+0 bare-rooted seedlings, unshaded or shaded with cardboard shadecards at planting) and unshaded 2+0 bare-rooted ponderosa pine were compared on a droughty south facing clear felling in Oregon. The site was clear felled and burned in 1982 and the seedlings were planted in 1983. Shading did not significantly increase survival of plugs, possibly because of a wetter than normal first summer, nor did shading affect growth of either Douglas fir stocktype 5 yr after planting. Bare-rooted Douglas fir remained significantly larger than plugs, but relative growth rates for the initially smaller plugs were significantly greater for diameter and volume. Survival and growth of ponderosa pine tended to be better than those of Douglas fir. It was concluded that both species appeared to be suitable for reforestation after clear felling on sites subject to drought.

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129.
Henry, C.L. 1987. Growth response, mortality, and foliar nitrogen concentrations of four tree species treated with pulp and paper and municipal sludges. In The-forest-alternative-for-treatment-and-utilization-of-municipal-and-industrial-wastes. Eds. Cole, D.W., C.L. Henry, and W.L. Nutter. University of Washington Press, Seattle, Washington, USA. pp. 258-265.

Keywords:      nursery operations

                        nursery fertilization

                        soil properties

                        growth

                        tree/stand health

                        tree physiology

Abstract: Four nursery beds at the University of Washington Charles Lathrop Pack Demonstration Forest were each divided into plots that received 8 sludge treatments before being planted with seedlings of Douglas fir, Abies procera or Pinus monticola, or cuttings of Populus deltoides X P. trichocarpa. Each sludge and the unamended soil were analysed for total solids, total C, P and K, total N and NH4-N. Ht. and diam. were measured after planting in April 1984 and again in Feb. 1985. N was determined in foliage sampled during Oct. (Populus) or Feb. (other species). Addition of pulp and paper sludge alone and combined with municipal sludge provided predictable growth responses when compared with the C : N ratio of each treatment. Av. response was positive when the C : N ratio was more favourable than that of untreated soil, but av. response was negative when soil was treated with primary pulp and paper sludge with a very high C : N ratio. Treatments that produced the greatest growth also increased seedling mortality.

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130.
Henry, C.L., D.W. Cole and R.B. Harrison. 1994. Use of municipal sludge to restore and improve site productivity in forestry: The Pack Forest Sludge Research Program. Forest-Ecology-and-Management 66(1/3): 137-149.

Keywords:      fertilization

                        growth

                        soil properties

                        stand conditions

Abstract: Municipal wastewater residuals - sludge or biosolids - represent a major waste by-product from society that must be managed in responsible ways. Because of its high nutrient and organic matter content, sludge can be beneficially recycled into forest sites for site improvement purposes. This paper reviews the opportunities and problems that have been encountered during 20 yr of research into sludge application in forests, based on data from studies carried out in the Pack Demonstration Forest, Washington, on a variety of sites - including clear-felled, young or mature Douglas fir [Pseudotsuga menziesii] stands, and rights-of-way. Research to date on forest application of sludge has been very encouraging, clearly demonstrating the validity of this management technique. Forest sites typically display benefits in two ways: (1) an immediate growth response by both overstorey and understorey species; (2) a long-term improvement to the productivity of the site. However, for this practice to have broad utility and acceptance, it is critical that the concerns of the regulatory agencies and general public be addressed regarding public health and environmental issues through continued research. These concerns include the fate of trace metals, including movement, uptake and potential phytotoxicity, and passage into wildlife and human food chains, the fate of pathogens, and leaching of nitrates into groundwater systems. Many concerns are a result of misconceptions or misunderstandings of the potential problems involved and require working with these agencies and the general public through education and demonstration programmes.

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131.
Henry, C.L., D.W. Cole, T.M. Hinckley and R.B. Harrison. 1993. The use of municipal and pulp and paper sludges to increase production in forestry. Journal-of-Sustainable-Forestry 1(3): 41-55.

Keywords:      nursery operations

                        nursery fertilization

                        fertilization

                        thinning

                        growth

                        tree/stand health

                        soil properties

Abstract: Because of their high nutritional content and soil conditioning properties, municipal and pulp and paper (P&P) sludges (biosolids) can serve as soil amendments for nutritionally deprived or organically poor soils on forest sites. Studies conducted over the past 20 years at an experimental forest site in Western Washington, USA, have largely confirmed the potential of biosolids to increase the productivity of many forest lands. These studies clearly demonstrated that application of biosolids at environmentally acceptable rates will result in growth responses for both young seedlings as well as established stands. Municipal biosolids have been applied to a number of Douglas fir (Pseudotsuga menziesii) stands. Young stands treated with 47 t/ha showed an average of 72, 14 and 2% height responses for Site Class IV, III and II, respectively, over a 10 year period. Thinned versus unthinned 55-year-old Douglas fir treated with 142 dry t/ha averaged 43 and 48%, respectively, for the 12 year period greater than controls. Average growth responses of 65 and 40% occurred in the 65-year-old stand for the Site Class IV and II, respectively, from a 47 dry t/ha application. Growth response resulting from application of P&P biosolids to a number of tree species (Douglas fir, Pinus monticola and Abies procera in nursery beds, and plots of Populus deltoides x P. trichocarpa rooted cuttings) has also been excellent. When properly applied, biosolids can provide an excellent alternative to chemical fertilizers as a means of enhancing forest production. Growth response is typically greater and lasts longer when compared with chemical fertilizers.

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132.
Hermann, R.K. and D.P. Lavender. 1999. Douglas-fir planted forests. New-Forests 17(1/3): 53-70.

Keywords:      genetic tree improvement

                        nursery operations

                        planting operations

                        site preparation

                        release treatments

                        fertilization

                        thinning

                        pruning

                        tree/stand protection

                        growth

                        yield

Abstract: A combination of superior wood quality and high productivity has made Douglas fir (Pseudotsuga menziesii) one of the premier timber trees in the world. As such, it is grown as a plantation species in several countries in Europe and South America, and in New Zealand and Australia, as well as throughout its extensive natural range in western North America. Decades of experience with the silviculture of young stands have demonstrated that practices such as planting, the use of genetically improved seedlings, precommercial and commercial thinning, and fertilizing may dramatically increase the yield of industrial products over that of natural forests. Further, such silviculture is compatible with the production of desired amenities. Vigorous implementation of such practices wherever Douglas fir is cultivated will increase the world's timber resources, and be an effective strategy for reducing the pressure, occasioned by the world's rapidly increasing population, to harvest the fragile tropical and boreal forests.

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133.
Hildebrand, D.M., J.K. Stone, R.L. James and S.J. Frankel. 2004. Alternatives to preplant soil fumigation for Western forest nurseries. Pacific-Northwest-Research-Station,-USDA-Forest-Service General-Technical-Report PNW-GTR-608. ii + 27 p.

Keywords:      nursery operations

                        nursery fertilization

                        tree/stand protection

                        tree/stand health

                        growth

Abstract: Field trials were conducted at six bare-root forest tree (Pinus ponderosa, Pseudotsuga menziesii, Pinus contorta and Abies magnifica var. shastensis) nurseries in the Western United States: Bend Pine Nursery in Bend and J. Herbert Stone Nursery in Central Point (Oregon), Coeur d'Alene Nursery and Lucky Peak Nursery in Idaho, and Humboldt Nursery near McKinleyville and Placerville Nursery near Camino (California). These field experiments compared cultural treatments including timing and depth of sowing; bare fallow (with and without periodic tilling); organic amendments including sawdust, composts, and cover crops; mulches including pine needles, sawdust, and rice straw; and fumigation with methyl bromide/chloropicrin or dazomet. Measured effects included population levels of potential soil-borne pathogens (species of Fusarium and Pythium), disease incidence, seedbed density, and sizes of conifer seedlings. Several non-fumigation treatments resulted in production of seedlings with densities and sizes similar to or better than those produced in beds treated with chemical fumigation. Results varied within the nurseries depending on conifer species, field history, and disease presence. Beneficial cultural practices included: (1) incorporation of slowly decomposing organic soil amendments, e.g., aged sawdust with additional nitrogen provided later to seedlings; (2) bare fallowing with periodic tilling, and bare fallowing without periodic tilling plus supplemental weed control; and (3) sowing of conifer seed earlier and more shallow than sown conventionally, and covering seed with a nonsoil mulch such as aged sawdust or hydromulch.

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134.
Hobbs, S.D. 1981. Stocktype selection and planting techniques for Douglas-fir on skeletal soils in southwest Oregon. In Reforestation of skeletal soils: proceedings of a workshop, Medford, OR, USA, November 17-19, 1981. Eds. S.D. Hobbs and O.T. Helgerson. pp. 92-96.

Keywords:      planting operations

                        tree/stand health

                        growth

Abstract: Stocktype selection and planting techniques for Douglas-fir can have a significant impact on seedling survival and growth on droughty skeletal soils in southwest Oregon. In these environments important seedling characteristics are stock quality, shoot-root ratio, root morphology, and caliper. Planting and special ameliorative techniques for sites with skeletal soils are discussed.

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135.
Hobbs, S.D., S.G. Stafford and R.L. Slagle. 1987. Undercutting conifer seedlings: effect on morphology and field performance on droughty sites. Canadian-Journal-of-Forest-Research 17(1): 40-46.

Keywords:      nursery operations

                        tree morphology

                        growth

                        tree/stand health

Abstract: One-yr-old barerooted Douglas fir and ponderosa pine seedlings in an Oregon nursery were subjected during Feb.-June 1980 to 5 undercutting treatments that varied by number and depth of cuts and seedling phenology at time of treatment. Eight morphological variables were measured in Jan. 1981 before planting the seedlings at 2 sites in Oregon. Seedling survival and growth was recorded annually for 4 yr. All treatments significantly reduced shoot growth in the nursery, but changes in root system morphology depended on treatment severity and species. Treatment effects were generally more pronounced in ponderosa pine than in Douglas fir. Discriminant analysis showed that seedlings responded similarly in all undercutting treatments relative to control seedlings that were not undercut. No effects of undercutting were apparent after 4 yr in the field.

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136.
Hobbs, S.D. and K.A. Wearstler, Jr. 1983. Performance of three Douglas-fir stocktypes on a skeletal soil. Tree-Planters' Notes 34(3): 11-14.

Keywords:      nursery operations

                        tree/stand health

                        growth

Abstract: Plug-1 bare rooted seedlings, initially grown in containers and transplanted to a nursery for 1 yr, 2-0 bare rooted seedlings and 1-0 plug stock were planted on a steep, severe site in the Siskiyon Mts., SW Oregon, in 1980. Height and diameter were recorded after planting and in the autumn in 1980 and 1981. Survival was 91% for 1-0 plug seedlings, 87% for plug-1 seedlings and 56% for 2-0 bare rooted stock. There were n.s.d. in height and diameter growth.

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137.
Hobbs, S.D. and K.A. Wearstler, Jr. 1985. Effects of cutting sclerophyll brush on sprout development and Douglas-fir growth. Forest-Ecology-and-Management 13(1/2): 69-81.

Keywords:      release treatments

                        manual release

                        stand conditions

                        tree physiology

                        growth

Abstract: In SW Oregon, varying amount of brush were removed from a sclerophyll brushfield dominated by Quercus chrysolepis and Arctostaphylos patula with scattered Pseudotsuga menziesii saplings. Brush removal was accomplished by slashing (cut by chainsaw) near ground level at three intensities: (1) total removal, (2) partial removal, and (3) an untreated control. Sclerophyll brush species responded within 3 weeks of slashing by vigorous sprouting, which was greatest in total brush removal areas where 861 513 sprout stems/ha developed during the first year. Soil water potentials and predawn xylem pressure potentials of Douglas fir were less negative in total removal areas than in partial removal and untreated control areas. Relative growth rates of Douglas fir saplings temporarily increased in total and partial brush removal areas, but were not significantly different from the untreated control 3 yr after treatment. Slashing of sclerophyll brush to release long-suppressed Douglas fir is not recommended because of rapid brush recovery by sprouting.

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138.
Hopmans, P. and H.N. Chappell. 1994. Growth response of young, thinned Douglas-fir stands to nitrogen fertilizer in relation to soil properties and tree nutrition. Canadian-Journal-of-Forest-Research 24(8): 1684-1688.

Keywords:      fertilization

                        growth

                        soil properties

                        tree physiology

Abstract: Application of 224 kg N/ha to young, thinned stands of Douglas fir (Pseudotsuga menziesii) at 35 sites in W. Oregon and Washington significantly increased basal area and volume increment over 8 years following treatment. However, response varied considerably between sites, and relative volume increment exceeded 10% at only 19 of the 35 sites. Response to applied N was evaluated in relation to forest floor and soil variables as well as to levels of N in foliage. Relative responses in basal area and volume were significantly correlated with total N concentration and the C/N ratio of the soil. However, these relationships explained only part (18-22%) of the observed variation in response. In contrast, relative response was strongly correlated with the level of N in the foliage of non-fertilized trees at 11 sites, accounting for 94% of the variation between sites. It is suggested that foliar N could be used to predict growth responses to N fertilizers in young thinned Douglas fir stands.

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139.
Hummel, S. and R. Hummel. 2004. Five-year thinning response of an overgrown Douglas-fir Christmas tree plantation. Western-Journal-of-Applied-Forestry 19(3): 171-174.

Keywords:      planting operations

                        thinning

                        growth

                        yield

                        economics

Abstract: A 15-year-old Douglas-fir Christmas tree plantation in western Oregon was thinned in 1996 according to regional sawtimber conversion guidelines. The plantation comprised two strata, distinguished by initial planting density (Area 1=5x5 ft and Area 2=10x10 ft). Unthinned control plots were established in both Area 1 and Area 2 at the time of the thinning treatment. Five years later, the quadratic mean diameter (QMD) in Area 1 (thinned) was 6.4 in. versus 5.2 in. in Area 1 (unthinned), while in Area 2 (thinned) the QMD was 11.4 in. compared to 9.3 in. in Area 2 (unthinned). Over the same period, the volume/ac in Area 1 (thinned) (1,080 ft3/ac) was nearly twice that of Area 1 (unthinned) (576 ft3/ac). In contrast, the volume/ac in Area 2 (thinned) (2,318 ft3/acre) was almost half that of Area 2 (unthinned) (4,264 ft3/ac). These results suggest that while thinning was timely for Area 1, the thinning treatment could have been delayed for Area 2. By plantation age 30, the treated units in Area 1 and Area 2 have estimated yields of 9.6 and 11.6 thousand bd ft (mbf), respectively, with no additional thinning. Given 2002 average prices for #3 sawmill grade logs, gross return at age 30 would range between $5,000 and $6,000/ac.

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140.
Hung, L.L.L. and J.M. Trappe. 1987. Ectomycorrhizal inoculation of Douglas-fir transplanted container seedlings with commercially produced inoculum. New-Forests 1(2): 141-152.

Keywords:      nursery operations

                        mycorrhizal response

                        growth

Abstract: Commercially produced vegetative inocula of Laccaria laccata and Hebeloma crustuliniforme successfully formed ectomycorrhizae with Douglas fir transplanted container (plug + 1) seedlings. After 4.5 months in containers, 83% and 90%, respectively, of short roots were mycorrhizal. L. laccata- or H. crustiliniforme-inoculated seedlings had significantly more mycorrhizal and total short roots than Pisolithus tinctorius-inoculated (4% mycorrhizal root tips) or uninoculated control seedlings. No significant differences were detected in seedling growth at the end of the container phase. After transplantation and growth in nursery beds for 17 months, mean new short root colonization of all seedlings was 80%. H. crustuliniforme persisted as a dominant mycorrhizal fungus on seedlings initially inoculated with this fungus. L. laccata-inoculated seedlings had 40% of their short roots colonized by L. laccata and another 40% by the native fungi Rhizopogon and Thelephora spp. All mycorrhizae of control seedlings and those inoculated with P. tinctorius were formed by fungi native to the nursery beds. A significant fungal treatment effect was detected for shoot height only. Control seedlings were significantly taller than L. laccata-inoculated seedlings after transplanting.

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141.
Jacobs, D.F., R. Rose and D.L. Haase. 2003a. Development of Douglas-fir seedling root architecture in response to localized nutrient supply. Canadian-Journal-of-Forest-Research 33(1): 118-125.

Keywords:      nursery operations

                        nursery fertilization

                        tree morphology

                        tree physiology

                        growth

Abstract: Three months following sowing, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were transplanted into pots with controlled-release fertilizer (CRF) applied at rates of 0, 8, 16, and 24 g/2200 cm3 soil as a single uniform layer beneath the root system. Seedlings were destructively harvested periodically, and roots were divided into vertical segments above (S1), within (S2), and below (S3) the fertilizer layer. Two months following transplant, the number of active root tips was positively correlated with CRF rate in S1 and negatively correlated with rate in S2 and S3. At 6 months, root penetration into S3 was severely restricted at 16 and 24 g. This was attributed to detrimental changes in soil osmotic potential in S2. Fertilizer improved seedling growth at 8 g after 6 months compared with controls but was inhibitory at 24 g. Photochemical quantum yield was higher in all CRF treatments compared with controls 3 months following transplant, which corresponded with rapid initial CRF nutrient release. Despite improvements in nutrient release technology with CRF, high application rates may result in excessive concentrations of fertilizer nutrients in media, which can restrict root penetration and negatively affect seedling growth. Conservative application rates and improvements in CRF technology will help reduce the potential for adverse effects on seedling development.

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142.
Jacobs, D.F., R. Rose, D.L. Haase and P.D. Morgan. 2003b. Influence of nursery soil amendments on water relations, root architectural development, and field performance of Douglas-fir transplants. New-Forests 26(3): 263-277.

Keywords:      nursery operations

                        fertilization

                        tree physiology

                        tree morphology

                        growth

                        carbon allocation

                        soil properties

                        tree/stand health

Abstract: This experiment evaluated the influence of manure, peat, and vermiculite incorporated at low and high rates (0.0118 and 0.0236 m3/m2) and under two soil moisture regimes on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling (1+0 for 1+1) xylem water potential ( Phi xylem), whole-plant growth, root architectural development, and subsequent field performance under fertilized and non-fertilized conditions. Trends in soil moisture retention were observed (high manure > high peat > control) but there were no differences in Phi xylem. Root length in the wetter soil moisture experiment was initially (three months) greatest for seedlings in high vermiculite and least in high manure but there were no differences among treatments at lifting (eight months). Mean height was greatest for seedlings grown in vermiculite and peat (wetter nursery experiment) after two field seasons. Field fertilization (35 g/seedling) with controlled-release fertilizer in the planting hole stimulated height growth initially, but decreased height and diameter growth during the second growing season. Dramatic improvements associated with the use of nursery soil amendments were not realized, but the failure to identify negative effects, a potential reduction in disease incidence, and improvement of nursery soil physical and chemical properties may justify their use.

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143.
Jaindl, R.G. and S.H. Sharrow. 1988. Oak/Douglas-fir/sheep: a three-crop silvopastoral system. Agroforestry-Systems 6(2): 147-152.

Keywords:      planting operations

                        release treatments

                        manual release

                        tree/stand health

                        growth

Abstract: A small scale agroforestry study started in 1952 was revisited in 1985 to evaluate the long-term influence of site preparation and grazing on tree growth and survival in a system with Douglas fir, white oak (Quercus garryana) and sheep. In 1952-53, 2-yr-old Douglas fir seedlings were planted at the rate of 2500 trees/ha under 3 levels of site preparation: (1) no treatment; (2) oak thinned by 50%; and (3) oak clear felled. From 1954 to 1960, yearling ewes grazed half of each of the 3 thinning treatments for 3-4 wk each spring. The conifers were undisturbed since grazing was discontinued in 1960. Survival of planted conifers averaged 64% in 1985 and did not vary among either site preparation or grazing treatments. From 1964 to 1985, trees on the thinned and clear felled plantations grew an av. ht. of 1060 and 990 cm, respectively, compared with 900 cm on the unthinned plantation. D.b.h. averaged 3.8 and 5.6 cm greater on thinned or clear felled plantations, respectively, than on the unthinned control by 1985. Conifers on grazed plantations had increased ht. and d.b.h. growth during the first 12 yr of plantation life, averaging 63 cm taller and 0.7 cm greater in d.b.h. than the ungrazed plots by 1964. By 1985 the difference in ht. (122 cm) and d.b.h. (1.0 cm) between grazed and ungrazed plantations was not statistically significant. These data suggest that although site preparation can positively influence conifer growth, total clear felling is no better than thinning oaks. Furthermore, proper grazing can increase ht. and d.b.h. growth of the conifers during and immediately after the grazing years.

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144.
Johnson, G.R. 2002. Genetic variation in tolerance of Douglas fir to Swiss needle cast as assessed by symptom expression. Silvae-Genetica 51(2/3): 80-86.

Keywords:      genetic tree improvement

                        tree/stand protection

                        tree/stand health

                        growth

                        genetic relationships

Abstract: The incidence of Swiss needle cast (caused by Phaeocryptopus gaeumannii) on Douglas fir (Pseudotsuga menziesii) has increased significantly in recent years on the Oregon coast. Genetic variation in symptoms of disease infection, as measured by foliage traits, was assessed in two series of progeny trials to determine whether these "crown health" indicators were under genetic control and correlated with tolerance (tolerance being continued growth in the presence of high disease pressure). Foliage traits generally had lower heritabilities than growth traits and were usually correlated with diameter growth. Foliage traits of crown density and colour appeared to be reasonable indicators of disease tolerance. In the absence of basal area data, assessing crown density and colour can help screen for families that show tolerance to the disease.

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145.
Johnson, G.R., R.A. Sniezko and N.L. Mandel. 1997. Age trends in Douglas-fir genetic parameters and implications for optimum selection age. Silvae-Genetica 46(6): 349-358.

Keywords:      genetic tree improvement

                        growth

                        genetic relationships

Abstract: Trends in genetic variation in Douglas fir (Pseudotsuga menziesii) were examined over 51 progeny test sites throughout western Oregon. Narrow sense heritabilities for height and diameter showed an increasing trend to age 25, the oldest age examined. Before age 10, height heritabilities were relatively unstable. Type B site-site genetic correlations increased slowly with age for height and remained relatively stable for diameter. Age-age correlations were used to develop an equation to predict age-age correlations by using the log of the age ratios (LAR). Optimum selection age was calculated for a 60-year rotation by using two measures of efficiency: gain per year and discounted gain. The optimum selection age for height tended to be 2 to 3 years earlier than for diameter. Gain per year was maximized at age 10 for height and age 13 for diameter.

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146.
Joseph, G. and R.G. Kelsey. 1999. Growth of Douglas-fir and ponderosa pine seedlings with foliar applications of methanol and ethanol. Western-Journal-of-Applied-Forestry 14(4): 183-185.

Keywords:      nursery operations

                        growth

                        tree morphology

                        tree/stand health

Abstract: Ethanol and methanol have been reported to enhance the growth and development of several agricultural and horticultural species. To test whether methanol or ethanol stimulated growth of coast Douglas fir (Pseudotsuga menziesii var. menziesii) or ponderosa pine (Pinus ponderosa)in the nursery, seedlings were sprayed with concentrations of 1 to 10% (v/v) on the foliage twice a week for 13 wk during the growing season. Foliar applications of methanol and ethanol neither significantly stimulated nor inhibited growth, and signs of damage at these concentrations were lacking.

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147.
Jozsa, L.A. and H. Brix. 1989. The effects of fertilization and thinning on wood quality of a 24-year-old Douglas fir stand. Canadian-Journal-of-Forest-Research 19(9): 1137-1145.

Keywords:      fertilization

                        thinning

                        wood quality

                        growth

Abstract: The effect of thinning and N fertilization on growth and wood density of coastal Douglas fir (Pseudotsuga menziesii) on a poor site on Vancouver Island (British Columbia) is described for plots established at approx. 24 yr old in 1971-72. Stem cores were taken using an increment borer in Mar.-Apr. 1984. Ring-width and ring-density data were obtained from pith to bark for all trees using computerized X-ray densitometry. Fertilization reduced ring density at b.h. and 25% stem ht. by an av. of 6% for a 3- to 4-yr period after treatment, but not thereafter. Reductions in ring density resulted from decreases in the density of earlywood and latewood, as well as from decreases in latewood percentages. Effects were only pronounced in the lower half of the stem. Thinning resulted in a slight increase in ring-density in the lower bole and a reduction in the top. The combined treatments had an intermediate effect on ring density. Ring density showed an increasing trend from pith to bark at all ht. except at 75% stem ht., and a decrease with increasing ht. in the bole. Fertilization and thinning both increased diam. growth, and the beneficial effects were still evident 13 yr after treatments.

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148.
Kastner, W.W., Jr., S.M. Dutton and D.M. Roche. 2001. Effects of Swiss needle cast on three Douglas-fir seed sources on a low-elevation site in the northern Oregon Coast Range: results after five growing seasons. Western-Journal-of-Applied-Forestry 16(1): 31-34.

Keywords:      genetic tree improvement

                        tree/stand protection

                        growth

                        tree/stand health

Abstract: Douglas-fir (Pseudotsuga menziesii var. menziesii) seedlings grown from three seed sources were evaluated for 5 years for their relative tolerance to Swiss needle cast (caused by the ascomycete Phaeoxryptopus gaeumannii), on a high-disease-hazard site located approximately 3 miles northeast of Tillamook, Oregon, USA. The seed sources were: (1) seed collected from trees showing an apparent degree of tolerance to Swiss needle cast in natural stands in the coastal fog belt, (2) open-pollinated seed orchard seed collected from random single-pair crosses of parent trees in natural stands outside of the coastal fog belt, but west of the Oregon Coast Range summit, whose progeny demonstrated an apparent degree of disease tolerance in coastal Douglas-fir progeny test sites, and (3) standard reforestation seed purchased from a commercial vendor. There were no significant differences among seed sources in basal diameter and total height for all five growing seasons. Needle retention varied among seed sources over the 5-year period, but current-year needle retention did not vary significantly after the fifth growing season, and retention of 1- and 2-year-old needles was relatively low for all seed sources. The intense disease pressure on this site may have overwhelmed expression of disease tolerance among seed sources. We do not recommend planting Douglas-fir on such high-hazard sites.

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149.
Kaya, Z. 1992. The effects of test environments on estimation of genetic parameters for seedling traits in 2-year-old Douglas-fir. Scandinavian-Journal-of-Forest-Research 7(3): 287-296.

Keywords:      genetic tree improvement

                        nursery operations

                        genetic relationships

                        growth

                        tree phenology

Abstract: The effects of test environments (dry versus wet) on the estimation of genetic parameters in seedling traits were studied in 160 open-pollinated families of Douglas fir (Pseudotsuga menziesii) from southwestern Oregon. Seedlings from four populations were grown in two test nursery environments between which a water potential difference of -9 bars was created over two growing seasons, by withholding water for 4 and 8 wk, respectively. Estimated genetic variances in most growth and phenology traits were considerably higher for seedlings grown in the wet environment than for those in the dry. Estimated genetic correlations between the same traits measured in different test environments indicated that most seedling traits studied for two growing seasons were genetically stable in both environments, suggesting that genotype environment interaction in these traits are weak. However, it is emphasized that the effect of test environment on estimation of genetic parameters in seedling traits, especially in adaptive seedling traits, should be evaluated very carefully when early evaluation of genetic entries is practised in Douglas-fir, since these traits (budburst timing, lammas growth and free growth) appear to be plastic in character.

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150.
Kaya, Z. 1993. Genetic variation in shoot growth components and their correlations in Pseudotsuga menziesii var. menziesii seedlings. Scandinavian-Journal-of-Forest-Research 8(1): 1-7.

Keywords:      genetic tree improvement

                        genetic relationships

                        growth

Abstract: Stem-unit measurements could be useful for early selection if these dimensions were highly heritable and strongly correlated with traits of commercial interest, such as height growth. Height increments and the number and length of stem segments were measured in the first and second growth period in predetermined and free growth of Douglas-fir (Pseudotsuga menziesii var. menziesii) seedlings from 40 families in each of 2 populations from southwestern Oregon, USA. Populations, or families in populations, exhibited genetic variation in all traits except number of stem units in predetermined growth. Heritabilities for stem-unit measurements were higher than those for height increment in the first growing season, but not in the second. Correlations among measurements of stem units and height increments were only moderate (generally <0.70). It is concluded that stem units are not likely to be better measurements of height in early selection of Douglas-fir than are measurements of either predetermined or free growth.

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151.
Kaya, Z., R.K. Campbell and W.T. Adams. 1989. Correlated responses of height increment and components of increment in 2-year-old Douglas fir. Canadian-Journal-of-Forest-Research 19(9): 1124-1130.

Keywords:      genetic tree improvement

                        tree phenology

                        growth

                        genetic relationships

Abstract: The consequences for growth and phenology of early selection for height or its growth components were evaluated in 160 open-pollinated families of Douglas fir (Pseudotsuga menziesii) from SW Oregon. Seedlings from 2 inland and 2 coastal populations (40 families each) were grown for 2 growing seasons in a 'moist' and 'dry' nursery environment. Predicted response to selection suggests that risk of low juvenile-mature correlation and maladaptation with early selection would be less in the inland than in the coastal region. Early bud set in the 1st yr was genetically correlated with larger overwintering buds in seedlings from both inland and coastal regions. These larger buds yielded a large increment of predetermined growth in the 2nd yr, followed by little or no free growth and early bud set. Seedlings with late bud set in the 1st yr had the converse pattern. Inland seedlings set buds much earlier on av. than coastal seedlings, hence seedlings from the 2 regions had different growth patterns. Risks that can attend early selection for ht. generally would be decreased in both regions by selecting for predetermined growth, but several qualifications are discussed.

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152.
Khan, S.R., R. Rose, D.L. Haase and T.E. Sabin. 1996. Soil water stress: its effects on phenology, physiology, and morphology of containerized Douglas-fir seedlings. New-Forests 12(1): 19-39.

Keywords:      nursery operations

                        growth

                        tree physiology

                        tree phenology

Abstract: Containerized 3-month-old Douglas fir (Pseudotsuga menziesii) seedlings were subjected to six moisture-stress treatment (ranging from 7 to 65% soil water content by volume) for 12 weeks. At the end of this period, there were significant differences in phenological, physiological, and morphological responses among the seedlings in the various moisture-stress treatments. In general, seedlings grown under very high or very low soil moisture conditions were adversely affected, while those grown under moderate conditions (29 to 53% water content) exhibited optimum growth, bud development, and nutrient and starch reserves. The use of vector analysis was found to be helpful in data interpretation. The results indicate the importance of closely monitoring nursery moisture regimes in order to achieve the best seedling quality.

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153.
Kimball, B.A., G.R. Johnson, D.L. Nolte and D.L. Griffin. 1999. An examination of the genetic control of Douglas-fir vascular tissue phytochemicals: implications for black bear foraging. Forest-Ecology-and-Management 123(2/3): 245-251.

Keywords:      genetic tree improvement

                        tree/stand protection

                        growth

                        tree physiology

                        genetic relationships

Abstract: Silvicultural practices can influence black bear (Ursus americanus) foraging preferences for Douglas fir (Pseudotsuga menziesii) cambial-zone vascular tissues, but little is known about the role of genetics. To study the impact of genetic selection, vascular tissue samples were collected from Douglas fir trees in 6 half-sib families from 5 different sites in north central Oregon. Four replications of 3-tree non-contiguous plots were sampled at each site to examine inter-and intra-site variation. Tree growth was measured as tree diameter at breast height, and the absolute concentrations of 26 different terpenoids were determined by gas chromatography/flame ionization detection from ethyl acetate extracts. The simple carbohydrates fructose, glucose, and sucrose, and the phenolic glycoside coniferin were quantified using anion-exchange chromatography with pulsed amperometric detection. Cluster analysis was used to reduce the number of variables used in analyses of variance. Results for the families studied here indicate that tree growth and some terpenoids were under some level of genetic control. Furthermore, allocation of constitutive terpenoids in vascular tissues was not at the expense of tree growth. The sugars present in vascular tissue were affected by environment (site) and genetics (family) and their interaction.

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154.
Kimball, B.A., D.L. Nolte, D.L. Griffin, S.M. Dutton and S. Ferguson. 1998a. Impacts of live canopy pruning on the chemical constituents of Douglas-fir vascular tissues: implications for black bear tree selection. Forest-Ecology-and-Management 109(1/3): 51-56.

Keywords:      pruning

                        tree/stand protection

                        growth

                        tree physiology

                        tree/stand health

Abstract: The impact of live canopy pruning (removal of all live and dead whorls between the ground and 5 m height, resulting in removal of ~40% of the live canopy) on the carbohydrate and terpene content of vascular tissue was investigated in the lower bole of Douglas fir (Pseudotsuga menziesii) on 4 sites in NW Oregon. Cambial zone vascular tissue samples were collected from pruned and unpruned trees in the lower bole and within the live canopy. Current year's radial growth was estimated from the mass of vascular tissue removed from the 800 cmsuperscript 2 area sampled from each tree. Chemical analyses were conducted to determine the concentration of carbohydrates and terpenes in the samples. Results indicated that 2 yr following treatment, pruning resulted in reduced growth and decreased carbohydrate content of the vascular tissue. Pruning had no effect on the terpene concentration of the vascular tissue. The impact of pruning on the foraging selection of black bears (Ursus americanus) was evaluated by surveying bear damaged trees in a 50 acre stand of pruned and unpruned timber. Odds ratios indicate that black bears were 4 times more likely to forage unpruned than pruned Douglas fir. Tree selection may be explained in part by the higher availability of carbohydrates in the unpruned tree with respect to the pruned tree.

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155.
King, J.E., D.D. Marshall and J.F. Bell. 2002. Levels-of-growing-stock cooperative study in Douglas-fir: report no. 17 - the Skykomish study, 1961-93; the Clemons study, 1963-94. Pacific-Northwest-Research-Station, USDA-Forest-Service Research-Paper PNW-RP-548. vii + 120 p.

Keywords:      thinning

                        commercial thinning

                        growth

                        yield

                        tree/stand health

Abstract: A study was conducted at the Skykomish Tree Farm, and at the Clemons Tree Farm, Washington, USA, to determine how the amount of growing stock in repeatedly thinned stands of Douglas Fir (Pseudotsuga menziesii) affects cumulative wood production, tree size and growth-growing stock ratios. Initial stands were thinned to the same level of growing stock so that all plots would have virtually the same growth potential except the unthinned controls. The Skykomish and Clemons stands were 24 and 19 years old, respectively, when the studies were started. Stand treatments were completed at ages 42 and 36, and measurements were continued to ages 56 and 50. After 32 years at Skykomish and 31 years at Clemons, the basal area per acre in the eight regimes ranged from 119-244 ft2 at Skykomish and 101-195 at Clemons. The corresponding gross yields in cubic feet per acre were 8709-13 579 at Skykomish and 6329-9072 at Clemons. Volume in thinnings were 18-53% of the gross yield. Stand treatments included four regimes with different combinations of heavy and light thinning and four regimes with constant intensities of thinning. Variable regimes were found to have consistent advantage over constant regimes. Within a given level of growing stock, the constant regimes are recommended for applications where wood production is the primary objective. A substantial increase in the yield was produced in all regimes during the post thinning holding period. Based on standing volume after the last thinning, the holding period of 4 years produced approximately 30% more volume in all regimes. Extending the period to 9 years produced approximately 70% more volume, and at 14 years, the standing volume was more than double the volume remaining after the last thinning. This extra yield enhanced by the high quality of the stands makes the length of the holding period an important factor in the scheduling of final harvest.

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156.
King, J.N., F.C. Yeh and J.C.H. Heaman. 1988. Selection of growth and yield traits in controlled crosses of coastal Douglas-fir. Silvae-Genetica 37(3-4): 158-164.

Keywords:      genetic tree improvement

                        growth

                        genetic relationships

Abstract: Analysis of variance of several yield traits including height, height increment, diameter and volume in a full-sib progeny test of Douglas fir (Pseudotsuga menziesii) on 2 sites in British Columbia revealed significant amounts of additive genetic variance but small and non-significant amounts of dominance genetic variance. Individual tree heritabilities were between 0.08 and 0.16 for growth traits and family heritabilities were between 0.55 and 0.73. Acceptable gains were predicted with progeny test re-selection (10% volume gain per unit selection intensity). Age 6 height was an effective selection trait, and correlated well with age 12 volume, giving 70% relative efficiency for family selection. Age 12 height measurement and height increment between 10 and 12 did not express significant genetic differences on the individual site analyses due in part to uncontrolled within-plot variation. Diameter showed higher heritabilities and was less sensitive to inadequacies in experimental design than the later height measurements. Index selection for stem volume also demonstrated that diameter was the most effective growth trait to predict the breeding value of parents for individual tree stem volumes.

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157.
Knapp, W.H., T.C. Turpin and J.H. Beuter. 1984. Vegetation control for Douglas-fir regeneration on the Siuslaw National forest: a decision analysis. Journal-of-Forestry 82(3): 168-173.

Keywords:      planting operations

                        site preparation

                        chemical preparation

                        mechanical preparation

                        prescribed fire

                        release treatments

                        chemical release

                        manual release

                        growth

                        yield

                        economics

Abstract: Records from 324 plantations in Oregon were used to calculate the effect on stocking of various methods of controlling competing vegetation before and after plantation establishment. A decision tree analysis using 6 management regimes on 5 stocking classes indicated that if no site preparation or release (other than broadcast burning to reduce fuels) were practised, the forest would produce 63% of the m.a.i. and 35% of the present net worth (PNW) expected if all means of control (chemical, manual and burning) were available and used. If only manual control methods were used 78% of the max. m.a.i. and 57% of the max. PNW would be expected. When all methods except phenoxy herbicides were available, the expected m.a.i. and PNW were reduced to no less than 90%. The yield reduction varied with aspect, and the type of prelogging vegetation. Declines were least on SW-facing sites that were originally predominantly conifers, and greatest on NE-facing slopes that had supported broadleaves. Limitations of the analysis are discussed.

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158.
Knowe, S.A. 1994a. Effect of competition control treatments on height-age and height-diameter relationships in young Douglas-fir plantations. Forest-Ecology-and-Management 67(1-3): 101-111.

Keywords:      release treatments

                        chemical release

                        manual release

                        growth

                        tree morphology

Abstract: Height-age and height-diameter models for plantations of young Douglas fir (Pseudotsuga menziesii var. menziesii) were examined in relation to vegetation management treatments. The models were developed from 10 years of measurements in a competition release study installed on six sites in the Coast Ranges of Oregon and Washington. Analysis of height growth patterns for dominant trees indicated significant differences between the total vegetation control treatment and operational release treatments or no treatment. The resulting height-age function depicted exponential growth patterns for the total vegetation control treatment and nearly linear patterns for the operational release treatment and no treatment. The height-diameter function was compatible with dominant height growth and quadratic mean diameter prediction functions. Different height-diameter curve shapes were associated with total vegetation control and the operational release and no treatments. The resulting function implied that Douglas fir trees of a given diameter and age were slightly taller when under interspecific competition, especially for trees with smaller diameters. The height-age and height-diameter functions may be used in conjunction with diameter distribution or stand table projection models developed for these data to predict dynamics and stand structure in young Douglas fir plantations.

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159.
Knowe, S.A. 1994b. Incorporating the effects of interspecific competition and vegetation management treatments in stand table projection models for Douglas-fir saplings. Forest-Ecology-and-Management 67(1-3): 87-99.

Keywords:      release treatments

                        chemical release

                        growth

                        tree morphology

Abstract: A stand table projection system based on individual-tree and stand-level models for young Douglas fir (Pseudotsuga menziesii var. menziesii) plantations was developed from and evaluated with remeasurement data from xeric sites in the Siskiyou Mountains of SW Oregon (established in a competition gradient study), and mesic sites in the Coast Ranges of Oregon and Washington (established in a treatment efficacy study). A projection equation was developed for relative tree size, defined as the ratio of individual-tree diameter at 15 or 30 cm above ground level (depending on the study location) to quadratic mean diameter. The relative size projection equation for the Coast Ranges study included the effect of total vegetation control, which indicated that diameters of Douglas fir receiving total vegetation control tended to become more uniform over time in the Coast Ranges. An additional equation was developed to project quadratic mean diameter so that individual-tree diameters could be estimated from projected relative size. The effect of vegetation management treatments on projected quadratic mean diameters in the Siskiyou study was expressed as an interaction between proportion of cover removed by treatments (intensity) and dominant height of Douglas fir at time of treatment relative to current dominant height. In 1- and 2-yr projection periods, the stand table projection system performed similarly to a diameter distribution prediction system based on a Weibull distribution function. However, the difference between projected and predicted diameter distributions became more pronounced as the projection period increased to 5 years.

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160.
Knowe, S.A., B.D. Carrier and A. Dobkowski. 1995. Effects of bigleaf maple sprout clumps on diameter and height growth of Douglas-fir. Western-Journal-of-Applied-Forestry 10(1): 5-11.

Keywords:      release treatments

                        growth

Abstract: Diameter and height growth of 7- to 11-yr-old Douglas fir (Pseudotsuga menziesii) were examined in relation to bigleaf maple (Acer macrophyllum) competition. Growth models were developed for plantations in Oregon and Washington by joining a distance dependent model with a model that excluded competition effects. The fitted equations were based on Douglas fir size at plantation age 7 yr and distance from the stump and crown diameter of the bigleaf maple clump. The model suggests that bigleaf maple clumps between 5.7 and 14.6 m from planted Douglas firs reduce the latter's d.b.h. and height growth, and that this reduction becomes greater with increasing size of the clump. A procedure is suggested to use the models to guide vegetation management prescriptions on sites with bigleaf maple sprout clumps.

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161.
Knowe, S.A., T.B. Harrington and R.G. Shula. 1992. Incorporating the effects of interspecific competition and vegetation management treatments in diameter distribution models for Douglas-fir saplings. Canadian-Journal-of-Forest-Research 22(9): 1255-1262.

Keywords:      release treatments

                        manual release

                        chemical release

                        growth

                        tree morphology

Abstract: A parameter recovery procedure for the Weibull distribution function, based on diameter percentiles, was modified to incorporate the effects of competing vegetation in young Douglas fir (Pseudotsuga menziesii var. menziesii) plantations. The procedure was tested using data from sites in the Coast Ranges of Oregon and Washington and in the Siskiyou Mountains of SW Oregon. The Coast Ranges study was conducted in 2- to 3-yr-old plantations needing release from woody shrub (mainly Rubus spectabilis and R. parviflorus) and broadleaved tree (Alnus rubra and Acer macrophyllum) competition. Release treatments were an untreated control, manual cutting, triclopyr ester applied aerially, glyphosate applied aerially, and a total vegetation control treatment consisting of annual broadcast applications of hexazinone and spot treatments of glyphosate and triclopyr. The Siskiyou Mountains study was conducted in 1- to 2-yr-old plantations on sites covered by tanoak (Lithocarpus densiflorus). Tanoak sprout clumps were left unthinned or were thinned to 50, 25 and 0% of the pretreatment cover. Four percentiles (0, 25th, 50th, 95th) of the cumulative probability distribution were predicted as functions of quadratic mean diameter and age. In the Siskiyou study, cover and total vegetation control affected quadratic mean diameter and all four percentiles; intensity of the vegetation treatments affected the 0 and 25th percentiles, and the interaction between intensity and timing of treatment affected mean diameter. In the Coast Ranges study, only quadratic mean diameter was affected by cover of woody vegetation, while quadratic mean diameter and the 25th percentile were significantly affected by total vegetation control. The predicted distributions showed decreasing variance with increasing cover, particularly in the Siskiyou Mountains. In the Coast Ranges study, the coefficient of variation increased with increasing cover, indicating that the variance of stem diameters was affected by average size. On xeric sites in the Siskiyou Mountains, high diameter variability in plots with total vegetation control suggests that interspecific competition may inhibit the expression of microsite variation.

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Non-OSU Link


162.
Knowe, S.A. and W.I. Stein. 1995. Predicting the effects of site preparation and protection on development of young Douglas-fir plantations. Canadian-Journal-of-Forest-Research 25(9): 1538-1547.

Keywords:      site preparation

                        release treatments

                        tree/stand protection

                        growth

                        tree morphology

                        tree/stand health

                        stand conditions

Abstract: Diameter prediction models based on the Weibull distribution function and stand-table projection models based on changes in relative diameter were developed for 2- to 10-year-old Douglas fir (Pseudotsuga menziesii) plantations in Oregon. Both modelling approaches incorporated the effects of site preparation, animal protection, and competing vegetation. The diameter distribution approach is appropriate when information on initial diameters is not available. The stand-table projection approach may be applied when tree diameters in a plantation are measured two or more growing seasons after planting. At young ages, the stand-table approach provided more accurate representation of observed diameter distributions than the diameter distribution approach. At age 10 the two methods provided comparable diameter distributions. The equations derived for predicting survival, height growth of dominant trees, height-diameter relationships, and the development of woody vegetation over time will facilitate the study and comparison of stand structure and dynamics after various site-preparation and animal protection treatments.

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Non-OSU Link


163.
Korpela, E.J., S.D. Tesch and R. Lewis. 1992. Plantations vs. advance regeneration: height growth comparisons for southwestern Oregon. Western-Journal-of-Applied-Forestry 7(2): 44-47.

Keywords:      planting operations

                        release treatments