1. 1997. PNWTIRC
Annual Report 1996-97,
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.
2.
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.
OSU
Link
Non-OSU
Link
3.
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.
4.
Keywords: genetic tree improvement
growth
Abstract: Data from a Douglas fir (Pseudotsuga menziesii)
open-pollinated progeny test in
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.
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.
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
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.
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
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
OSU
Link
Non-OSU
Link
10. Arnott, J.T. and D. Beddows.
1982. Influence of Styroblock container size on field performance of
Douglas-fir, western hemlock, and
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
11. Arnott, J.T. and F.T. Pendl.
1994. Field performance of several tree species and stock types planted in
montane forests of coastal
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.
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
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
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
15. Barclay, H., H. Brix and C.R.
Layton. 1982. Fertilization and thinning effects on a Douglas-fir ecosystem at
Keywords: fertilization
thinning
growth
Abstract: Further
results are given for a trial established in 1970 in a 24-yr-old stand in
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.,
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.
18. Barclay, H.J. and H. Brix. 1985b.
Fertilization and thinning effects on a Douglas-fir ecosystem at
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
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',
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
Non-OSU Link
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.
21. Beddows, D. 2002.
Levels-of-growing-stock cooperative study in Douglas-fir: Report No. 16 -
Keywords: thinning
growth
tree
morphology
Abstract: Results
from the two levels-of-growing-stock installations at
22. Berch, S.M. and A.L. Roth. 1993. Ectomycorrhizae and growth
of Douglas-fir seedlings preinoculated with Rhizopogon vinicolor and outplanted
on eastern
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.
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
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
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.
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
27. Birot, Y. and C. Christophe.
1983. Genetic structures and expected genetic gains from multitrait selection
in wild populations of Douglas fir and
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.,
OSU
Link
Non-OSU Link
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
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.
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.
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.
32. Brand, D.G. 1986a. A competition
index for predicting the vigour of planted Douglas-fir in southwestern
Keywords: planting operations
tree/stand health
growth
Abstract: As a
method of quantifying brush competition, data from 124 planted
33. Brand, D.G. 1986b.
Competition-induced changes in developmental features of planted Douglas-fir in
southwestern
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 comp