1. Bailey, J.D. and J.C. Tappeiner.
1998. Effects of thinning on structural development in 40- to 100-year-old
Douglas-fir stands in western Oregon. Forest-Ecology-and-Management 108(1/2): 99-113.
Keywords: thinning
commercial thinning
regeneration
tree morphology
Abstract: The
composition and structure of the understorey was
studied in thinned and unthinned Douglas fir/western
hemlock (Pseudotsuga menziesii/Tsuga
heterophylla) stands on 32 sites in western Oregon. These stands had regenerated naturally after timber was
harvested between 1880 and 1940; they were thinned between 1969 and 1984.
Commercially thinned stands had 8-60% of their volume removed 10-24 yr before
the study (in 1993-95). Undisturbed old-growth Douglas fir stands were present
for comparison on 20 of these paired sites. Conifer regeneration density and
frequency were consistently greater in thinned than unthinned
stands. For example, average seedling density in thinned stands (1433/ha) was
significantly greater than in unthinned stands
(233/ha), but very similar to that in old-growth stands (1010/ha). Seedling
density and frequency were strongly related to the volume removed and to stand
density index (and other measures of overstorey
density) just after thinning. In thinned stands, the density of small trees
(intermediate crown class overstorey trees and
advanced regeneration) was 159/ha, significantly greater than in unthinned stands (90/ha), but not significantly different
from that of old-growth (204/ha). The live crown ratio of these trees in
thinned stands (66%) was greater than in unthinned
(44%) and old-growth (48%) stands. Cover and stem density of shrubs was
variable in all 3 stand types. There was significantly less tall shrub cover in
unthinned stands than in either thinned or old-growth
stands, which did not differ. Thinned stands had the most low shrub cover. Salal (Gaultheria shallon) and
bracken fern (Pteridium aquilinum)
cover was greater in thinned stands than in the other stand types, but there
was no difference in sword fern (Polystichum munitum) and Oregongrape [Berberis nervosa] cover. Leaf area index in thinned stands
(6.6) was not significantly different from that in unthinned
(6.8) and old-growth stands (7.1); however, there was more leaf area in shrubs
in the thinned stands. Thinning young Douglas-fir stands will hasten the
development of multistorey stands by recruitment of
conifer regeneration in the understorey as well as by
enabling the survival of small overstorey trees and
growth of advanced understorey regeneration. Thinning
will also help develop the shrub layer by increasing tall shrub stem density
and cover of some low shrubs.
OSU
Link
Non-OSU
Link
2. Barclay, H.J. and J.A. Trofymow. 2000. Relationship of readings from the LI-COR
canopy analyzer to total one-sided leaf area index and stand structure in
immature Douglas-fir. Forest-Ecology-and-Management 132(2/3): 121-126.
Keywords: fertilization
thinning
tree morphology
Abstract: Estimation
of leaf area is important in predicting potential growth. This estimation is
often done by means of a photometer, such as the LI-COR plant canopy analyser, but such instruments generally give biased
estimates. Consequently, conversion factors are required to convert output from
the photometer to the actual leaf area index (LAI). Foliar biomass was
estimated in a 52-year-old Douglas fir (Pseudotsuga menziesii) stand at Shawnigan in British Columbia, Canada, which had been treated with 3 levels of thinning and 3
levels of fertilizer 28 years previously. The 4 treatment extremes (no thinning
or fertilizing, no thinning and heavy fertilizing (448 kg N/ha as urea), heavy
thinning (to 1/3 basal area) and no fertilizing, and heavy thinning and heavy
fertilizing) were sampled for foliage. Projected leaf areas were calculated
from these biomass samples using specific leaf areas derived in a previous
biomass sampling. Total one-sided leaf area was then computed by dividing the
projected leaf areas by 0.9 to allow for lateral leaf curvature. In addition,
LAI-2000 readings were taken in the same plots and then factors were derived to
convert LAI-2000 readings to total one-sided LAI. These conversion factors were
found to vary strongly with quadratic mean diameter, stand density, mean
diameter at breast height, mean height and stand basal area. The effect of live
crown height was minimal. These should allow the prediction of the conversion
factor based on 2 or 3 of these highly correlated factors.
OSU
Link
Non-OSU
Link
3. 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.
OSU Link
Non-OSU
Link
4. 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.
OSU
Link
Non-OSU
Link
5. 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.
OSU
Link
Non-OSU Link
6. 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.
OSU
Link
Non-OSU Link
7. Blake, J.I., R. Linderman and D. Lavender. 1988b.
Seedling vigor of Douglas fir and western hemlock in relation to ethylene
exposure levels and ethane production during cold storage. 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. 235-242.
Keywords: nursery operations
tree morphology
tree phenology
tree/stand health
Abstract: The
effects were examined of ethylene treatment on Pseudotsuga
menziesii and Tsuga heterophylla 2-yr-old bare root seedlings lifted in October
or December (in a nursery in Washington) and stored for 2 and 7 days. Seedlings exposed to 0.5 p.p.m. ethylene at +1 degrees C for 7 days exhibited
reduced bud and root activity. These effects were apparently reversed at 5.0 p.p.m. In a second experiment, reducing ethylene
concentrations with KMnO4 during storage at +1 or +10 degrees C for 30 days did
not affect foliage colour, but root and bud activity
were generally enhanced. Ethylene concentrations in control bags ranged from
0.80 to 2.24 p.p.m. in October-lifted seedling bags
and from 0.10 to 1.3 p.p.m. in December-lifted
samples. The quantity of ethane in stored bags of P. menziesii
seedlings was closely related to an increase in foliage discoloration. Little
or no ethane was measured in T. heterophylla storage
bags.
Non-OSU Link
8. Blake, J.I. and R.G. Linderman. 1992. A note on root development, bud activity,
and survival of Douglas-fir, and survival of western hemlock and noble-fir
seedlings, following exposure to ethylene during cold storage.
Canadian-Journal-of-Forest-Research 22(8): 1195-1200.
Keywords: nursery operations
tree morphology
tree phenology
tree/stand health
Abstract: Three
cold storage experiments were conducted with bare-root (2+0) Douglas fir (Pseudotsuga menziesii) seedlings
from coastal Oregon and eastern Washington Cascade sources. The objectives
were to determine the effects of ethylene at ambient and below-ambient
(absorbed by KMnO4 pellets) concentrations, and at 0.5 and 5 p.p.m. ethylene, during short-term storage on subsequent
root development and bud activity, and to relate these results to survival in
the field at sites in Washington and Oregon, after prolonged cold storage. Root
numbers and lengths were measured 28 days after a 7-day storage period after
lifting seedlings on 27 September and 1 December. In the coastal source, root
numbers and lengths in the 5 p.p.m. ethylene treatment were, respectively, 46 and 49% greater in
September, and 22 and 13% greater in December, than the controls. No comparable
treatment effects were found for the Cascade source. Neither the KMnO4 nor the
0.5 p.p.m. ethylene treatments affected root
development in either seed source. For terminal buds in the controls, the
number of days to 50% bud break was increased 2-8 days by a 30-day cold storage
period compared with a 7-day period. For the coastal source, no increase in the
time to 50% bud break was observed in the 5 p.p.m.
ethylene treatment. Seedling survival was evaluated in the field for the same
treatments following 4 months cold storage for the Douglas fir sources, coastal
western hemlock (Tsuga heterophylla),
and noble fir (Abies procera).
Survival for the 5 p.p.m. ethylene treatment compared
with the control was increased by 55% in the coastal Douglas fir source and by
13% in western hemlock. These results suggest that stimulated root development
and bud activity may be partially responsible for the observed survival
increase following cold storage at elevated ethylene levels.
OSU
Link
Non-OSU
Link
9. 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.
OSU Link
Non-OSU
Link
10. 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.
OSU
Link
Non-OSU
Link
11. 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.
OSU
Link
Non-OSU
Link
12. 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.
OSU Link
Non-OSU
Link
13. Brix,
H. and A.K. Mitchell. 1983. Thinning and nitrogen fertilization effects on
sapwood development and relationships of foliage quantity to sapwood area and basal
area in Douglas-fir. Canadian-Journal-of-Forest-Research 13(3): 384-389.
Keywords: fertilization
thinning
tree morphology
tree physiology
Abstract: A
24-yr-old stand in British Columbia was treated in 1971-72 with various intensities and combinations
of N fertilization and thinning. For 5-9 yr after treatments, trees were
sampled to determine effects on foliage quantity and sapwood characteristics at
varying stem ht. together with their relationships. Sapwood width remained
relatively constant up the stem where heartwood was present, but the number of
annual rings it contained decreased with ht. The sapwood width at b.h. increased with stem diam.;
treatments had little effect on % sapwood at b.h. The
ratio of foliage mass to sapwood cross-sectional area changed for different
portions of the crown and was lower when based on sapwood area at b.h. than at base of live crown. Significant linear
relationships of foliage mass and area to sapwood area at b.h.
were found, but relationships of foliage to b.a. were just as close for all treatments;
treatments significantly affected these relationships with control trees having
the lowest regression slopes.
OSU
Link
Non-OSU
Link
14. 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.
OSU Link
Non-OSU Link
15. 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.
OSU Link
Non-OSU
Link
16. 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.
OSU
Link
Non-OSU
Link
17. 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.
OSU
Link
Non-OSU
Link
18. Chen, J.M. and T.A. Black. 1992.
Foliage area and architecture of plant canopies from sunfleck
size distributions. Agricultural-and-Forest-Meteorology 60(3/4): 249-266.
Keywords: thinning
pruning
tree morphology
Abstract: A
Poisson model is developed to describe sunfleck or
gap size distributions beneath clumped plant canopies. This model is based on
the assumption that foliage clumps are randomly distributed in space and
foliage elements are randomly distributed within each clump. Using this model,
the foliage clumping index, leaf area index (L), clump area index, element area
index in each clump, and element and clump widths were successfully derived for
two artificial canopies and a thinned and pruned Douglas-fir (Pseudotsuga menziesii) forest
stand. It is shown that existing theories for deriving L from measurements of
canopy gap fraction have limitations, and use of canopy architectural
information derived from canopy gap size distribution can substantially improve
the technique for indirectly measuring L of plant canopies.
OSU
Link
Non-OSU
Link
19. 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.
OSU
Link
Non-OSU
Link
20. Coleman, M.D., C.S. Bledsoe and
B.A. Smit. 1990. Root hydraulic conductivity and
xylem sap levels of zeatin riboside
and abscisic acid in ectomycorrhizal
Douglas fir seedlings. New-Phytologist 115(2):
275-284.
Keywords: nursery operations
nursery fertilization
tree
morphology
tree physiology
mycorrhizal response
Abstract: The hypothesis that root hydraulic conductivity (LP) of ectomycorrhizal
root systems is greater than that of non-mycorrhizal
systems, and different to that of vesicular-arbuscular
(VA) mycorrhizas was tested in a greenhouse
experiment, by measuring hydraulic qualities of roots while accounting for
seedling size and P content. Plant growth substances (abscisic
acid and zeatin riboside)
expressed from roots during the experiments were also
measured. Douglas fir (Pseudotsuga menziesii) seedlings inoculated with the ectomycorrhizal fungi Laccaria
bicolor and Hebeloma crustuliniforme,
and non-inoculated seedlings infected naturally with Thelephora
were grown under 3 rates of P fertilization (1, 10 and 100 micro M P). After 9
months, seedling morphology, tissue P concn., LP and plant growth substance concn.
in xylem sap were measured. Increased tissue P and
decreased root/shoot ratio correlated with increased LP in each mycorrhizal treatment; when adjusted for the effect of
these 2 factors, LP of Laccaria and Hebeloma seedlings was still lower than that of Thelephora seedlings. In a subsequent experiment, LP of
seedlings with Hebeloma and Rhizopogon
vinicolor mycorrhizas was
compared with that of non-mycorrhizal seedlings
(grown at 100 mM P) and no differences were found
among treatments. The lack of an ectomycorrhizal
effect on LP is quite different from the enhancement of host LP by VA mycorrhizas. Zeatin riboside concentrations of Thelephora-
and Hebeloma-infected seedlings were similar, yet
higher than with Laccaria. There was no relationship
between plant growth substances and LP in ectomycorrhizal
Douglas fir, despite lower zeatin riboside
concentrations for Laccaria-inoculated plants.
OSU
Link
Non-OSU
Link
21. 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.
OSU
Link
Non-OSU
Link
22. Collier, R.L. and E.C. Turnblom. 2001. Epicormic
branching on pruned coastal Douglas-fir. Western-Journal-of-Applied-Forestry
16(2): 80-86.
Keywords: pruning
thinning
wood quality
tree morphology
Abstract: The
Stand Management Cooperative (SMC 1998) at the University of Washington, USA,
conducted live crown reduction experiments in the Pacific Northwest regions of
the USA, to better understand the dynamics of the response of coastal Douglas
fir (Pseudotsuga menziesii)
to pruning. A detailed report on how frequently epicormic
branches occur, where they occur on the bole, whether or not their occurrence
is related to stand density or the amount of crown removed, and how epicormic sprouting may affect log grade, is presented. The
experiments include fifty-six 0.08 ha pruning plot in 18 installations in British Columbia, Oregon and Washington. As part of the monitoring process, a subset of 38 plots
in 12 installations was examined for the occurrence and size of epicormic branches 4 years after the initial pruning
treatments. Results showed that epicormic branching
was most severe on the south and west sides of trees. When epicormic
branching was severe, sprouts occurred both at nodes (or whorls) and along
internodes. Less severe or moderate sprouting tended to originate mainly in
nodes. The risk of epicormic branching is minimal as
long as the pruning treatment does not reduce the live crown by more than 40%
and the stand has 500 or more stems/ha. The highest risk of epicormic
branching was found to be when the live crown is reduced by more than 40%, and
the stand carries less than 500 stems/ha.
OSU
Link
Non-OSU Link
23. 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.
OSU Link
Non-OSU
Link
24. Copes, D.L. and N.L. Mandel.
2000. Effects of IBA and NAA treatments on rooting Douglas-fir stem cuttings.
New-Forests 20(3): 249-257.
Keywords: nursery operations
tree morphology
tree/stand health
Abstract: The
effectiveness of 6 indole-3-butyric acid (IBA) and four 1-napthaleneacetic acid
(NAA) concentrations, 4 combinations of IBA and NAA concentrations, and control
were tested for their ability to enhance rooting frequency of Douglas-fir [Pseudotsuga menziesii] cuttings.
Two IBA and one NAA treatments were also compared to the control for quality of
root system. Between 1984 and 1998, six independent studies were conducted in
mist or fog environments with the 14 clones. Auxin
concentrations tested ranged from 0 to 123 mM IBA and
0 to 10 mM NAA. Auxin,
clone and auxin by clone effects were significant in
every study, although individual clone analyses showed only two clones to
differ significantly for auxin. All auxin treatments except the 10 mM
NAA treatment induced significantly greater rooting percentage than the
control, but no single auxin, auxin
concentration or combination of auxins was clearly
superior in every study. The 10 mM NAA concentration
was the only concentration tested that reduced rooting percentage to less than
the control. Both NAA and IBA appeared to have broad ranges of root-enhancing
activity. However, within the effective range of IBA evaluated, 24.6 or 49.3 mM produced the greatest rooting percentage in 4 of 5
studies testing IBA. NAA solutions with concentrations between 2.5 and 7.5 mM NAA generally resulted in similar rooting success.
Rooting responses to increased IBA and NAA were both nonlinear; rooting
decreased with both too little and too much auxin.
Combinations of IBA and NAA in the same solution did not increase rooting
percentage above what was achieved with one auxin.
For root system quality, auxin treated cuttings in
one study, had significantly better root systems than control, but there was no
difference in the other study in which root quality was estimated.
OSU Link
Non-OSU Link
25. 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.
OSU
Link
Non-OSU Link
26. 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.
OSU
Link
Non-OSU
Link
27. 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.
OSU
Link
Non-OSU
Link
28. 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.
OSU
Link
Non-OSU
Link
29. 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.
OSU
Link
Non-OSU Link
30. 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.
OSU
Link
Non-OSU
Link
31. Driessche,
R.v.-d. 1987. Importance of current photosynthate to new root growth in planted conifer
seedlings. Canadian-Journal-of-Forest-Research 17(8): 776-782.
Keywords: nursery operations
tree physiology
photosynthesis
tree morphology
Abstract: Reports
are given of 6 experiments. Two-yr-old seedlings of Douglas fir and Sitka spruce, labelled with 14CO2 in
Oct. and kept outdoors, contained 14C in old roots but little in new roots when
placed in a growth chamber in Jan. New roots were highly radioactive in
seedlings labelled with 14CO2 after 12 days' growth
in Jan., indicating that current photosynthate was
the primary C source for new roots. These results agreed with an experiment in
which the number and wt. of new roots on 1+1 Douglas fir transplants were
directly related to light intensity. Net photosynthesis (Pn)
of similar Douglas fir nursery stock after cold storage was inadequate to
supply C for respiration and new root growth under 16-h photoperiods of 200 micro E/msuperscript 2 per s,
although new root growth occurred. This suggested that reserves contributed to
respiration. Douglas fir seedlings began transpiration immediately after
planting in moist soil. Two-yr-old lodgepole pine
seedlings grown outdoors over winter with root systems maintained at <more
or =>10 degrees C produced more new roots in spring than seedlings grown
outdoors without heated roots or in a greenhouse; no relations were observed
between new root growth and Pn.
OSU
Link
Non-OSU
Link
32. 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.
OSU
Link
Non-OSU
Link
33. 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.
OSU
Link
Non-OSU
Link
34. 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.
OSU
Link
Non-OSU
Link
35. 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.
OSU Link
Non-OSU
Link
36. 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.
OSU
Link
Non-OSU Link
37. 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.
OSU
Link
Non-OSU
Link
38. Grotta,
A.T., B.L. Gartner and S.R. Radosevich. 2004.
Influence of species proportion and timing of establishment on stem quality in
mixed red alder-Douglas-fir plantations. Canadian-Journal-of-Forest-Research
34(4): 863-873.
Keywords: planting operations
tree morphology
wood quality
Abstract: The
relationships among stand structure, Douglas-fir (Pseudotsuga
menziesii) branch characteristics, and red alder (Alnus rubra) stem form attributes
were explored for 10- to 15-year-old trees growing in mixed Douglas-fir-red
alder plantations in Oregon, USA. Treatments included a range of species
proportions, and red alder was either planted simultaneously with Douglas-fir
or after 5 years. Both replacement effects (total stand density held constant)
and additive effects (stand density doubled) of competition were considered.
When the two species were planted simultaneously and red alder proportion was
low, red alder trees had low crown bases and much stem defect (lean, sweep, and
multiple stems). Douglas-fir grew slowly when the two species were planted
simultaneously. When red alder planting was delayed, species proportion did not
affect red alder stem form, and height to the base of the Douglas-fir live
crown decreased with increasing red alder proportion. Doubling Douglas-fir
density increased the height to the base of the Douglas-fir live crown;
however, doubling stand density by adding red alder did not affect Douglas-fir
crown height. Douglas-fir lumber coming from mixed stands may be inferior
because of the changes in knot characteristics associated with these different
patterns of crown recession. In stands with a low proportion of red alder, red
alder product recovery may be compromised because of the stem defects described
above.
OSU
Link
Non-OSU
Link
39. 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.
OSU
Link
Non-OSU Link
40. 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.
OSU
Link
Non-OSU Link
41. 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.
OSU
Link
Non-OSU
Link
42. 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.
OSU
Link
Non-OSU
Link
43. 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.
OSU Link
Non-OSU Link
44. 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.
OSU
Link
Non-OSU Link
45. Jozsa, L.A.
and G.R. Middleton. 1994. A discussion of wood quality attributes and their
practical implications. Forintek Canada Corp. 42 p.
Keywords: planting
operations
wood quality
tree morphology
Abstract:
Wood quality is defined as the suitability of wood for a particular
end-use. Wood anatomy and tree growth are discussed in terms of macroscopic and
microscopic features of a tree examined in cross section. End-use requirements
are described in terms of lumber grading. The following wood quality attributes
are introduced, defined and discussed in terms of their practical implications
for wood processing and wood products: wood density, density variation, juvenile wood/mature wood distribution, proportion of
heartwood/sapwood, fibre length, fibril angle,
compression wood, knots, grain and extractives. The potential for influencing
tree growth characteristics (e.g. wood density, branch size) and wood quality (structural
and appearance lumber grades) through stand stocking control is discussed.
OSU Link
Non-OSU
Link
46. Kershaw, J.A., Jr. and D.A. Maguire. 1996. Crown structure in
western hemlock, Douglas-fir, and grand fir in western Washington:
horizontal distribution of foliage within branches.
Canadian-Journal-of-Forest-Research 26(1): 128-142.
Keywords: fertilization
tree morphology
Abstract:
Horizontal distribution of foliage within individual branches was explored for
western hemlock (Tsuga heterophylla),
Douglas fir (Pseudotsuga menziesii)
and grand fir (Abies grandis),
three major tree species in the Pacific Northwest.
Weibull, beta , normal, and
Johnson's SB distributions were assessed for their ability to conform to the
empirical foliage distributions. Moment-based parameter recovery and parameter
prediction methodologies were applied. On the basis of the rank of individual
branch chi superscript 2-values, the beta distribution performed best under
parameter recovery, while Johnson's SB distribution was best in terms of total
sum of chi superscript 2-values. Overall, few differences between the four
distributions were observed. A system of moment-based parameter prediction
equations was developed from branch dimensional and positional measures. The
prediction equations showed that the ratio of relative distances from the stem
to mean foliage density increased with increasing branch size. This relative
increase was enhanced with increasing depth into crown for western hemlock, but
not for Douglas fir or grand fir. Again, the beta distribution, based on
predicted moments, followed most closely the empirical distributions on the
basis of the ranks of chi superscript 2-values. The normal distribution was the
best in terms of total sum of chi superscript 2-values. As expected,
moment-based parameter recovery produced smoothed distributions that followed
more closely the observed empirical distributions; however, parameter
prediction provides a methodology for predicting distributions when empirical
moments are not available. No significant (p >0.05) differences in
horizontal foliage distribution were found between sites or fertilizer (0 or
225 kg N/ha as urea) treatments.
OSU
Link
Non-OSU
Link
47. 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.
OSU
Link
Non-OSU Link
48. 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.
OSU
Link
Non-OSU
Link
49. 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.
OSU
Link
Non-OSU
Link
50. 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.
OSU
Link
Non-OSU
Link
51. Lopushinsky, W. and T.A. Max. 1990.
Effect of soil temperature on root and shoot growth and on budburst timing in
conifer seedling transplants. New-Forests 4(2): 107-124.
Keywords: planting
operations
tree morphology
tree phenology
tree physiology
Abstract:
Results are presented of studies of tree seedling morphological
responses to a wide range (0-30 degrees C) of soil temperatures and the effects
of soil temperature on needle water potential and stomatal
conductance in ponderosa pine (P. ponderosa). Bare-root 2-year-old seedlings
from high-altitude seed sources in the Cascade
Mountains (Washington
and Oregon
states) were used for the morphological study. Root growth in Douglas fir (Pseudotsuga menziesii), Pacific
silver fir (Abies amabilis),
noble fir (Abies procera), lodgepole pine (Pinus contorta) and ponderosa pine began when soil temperature
exceeded 5 degrees C. Root growth increased rapidly after 10 degrees C and
attained maximum values at 20 degrees C. At 30 degrees C, no root growth
occurred in the firs; in the pines, root growth was 30 to 39% of maximum.
Maximum shoot growth also occurred at 20 degrees C. In ponderosa pine, height
growth of seedlings from a high-altitude source was unaffected by cold soil,
but in low-altitude seedlings it was reduced. Budburst in Douglas fir and the pines
was delayed up to 11 days by cold soil, whereas in silver fir and noble fir, it
was only slightly delayed. Prior to new root growth in ponderosa pine, xylem
pressure potentials and stomatal conductances
during the afternoon indicated reduced stomatal
opening at all soil temperatures, whereas 23 days later, stomata were open to a
greater degree when temperatures exceeded 10 degrees C. Implications of these
results are briefly discussed: although root growth was initiated at soil
temperatures of 5 degrees C, this does not imply that seedlings should not be
transplanted until soils reach that temperature.
OSU
Link
Non-OSU Link
52. Lu, S., K.G. Mattson, J.B. Zaerr and
J.D. Marshall. 1998. Root respiration of Douglas-fir seedlings: effects of N
concentration. Soil-Biology-and-Biochemistry 30(3): 331-336.
Keywords: nursery
operations
nursery fertilization
growth
carbon allocation
tree morphology
tree physiology
mycorrhizal response
Abstract:
Six-month-old Douglas-fir (Pseudotsuga menziesii) seedlings were grown at three N concentrations
and with controlled root temperatures in Oregon,
USA.
Measurements of root respiration were conducted on undisturbed root systems by
passing humidified air with 1000 micro l/litre CO2
through root boxes onto an infrared gas analyser. The
effects of N on soil respiration were sought by examining total root
respiration rate per seedling, specific root respiration rate/g root dry wt,
and root dry wt after N fertilization. Total respiration rates of seedlings
grown at 50 mg N/litre concentration were
significantly higher than those grown at 10 or 200 mg N/litre.
Seedlings grown at N concentration of 200 mg/litre
had significantly smaller roots than those grown at the two lower N
concentrations. The specific respiration rate increased as N concentration was
increased from 10 to 50 mg N/litre, but remained
constant as N was further increased from 50 to 200 mg/litre.
The increase of total respiration rate with the increase in N concentration
from 10 to 50 mg/litre was attributed to the increase
in specific respiration, whereas the subsequent decrease in total respiration
with the increase in N concentration from 50 to 200 mg/litre
was attributed to the decrease in root dry wt. The depression of soil
respiration after the addition of N fertilizers to relatively fertile soil may
be explained by reduced root and mycorrhizal mycelial growth.
OSU
Link
Non-OSU
Link
53. Maguire, D.A. and W.S. Bennett. 1996. Patterns in vertical
distribution of foliage in young coastal Douglas-fir.
Canadian-Journal-of-Forest-Research 26(11): 1991-2005.
Keywords: thinning
precommercial thinning
tree morphology
Abstract:
Variation in foliage distribution was analysed
on trees and plots in a series of even-aged Douglas fir (Pseudotsuga
menziesii) stands scheduled for management under a
wide range of silvicultural regimes in British
Columbia, Washington
and Oregon.
Branch-level foliage mass and foliage area equations were developed from a
sample of 138 branches. These equations were applied to 27 trees on which the
diameter and height of all live primary branches were measured, allowing
estimation of both the total amount of foliage and its vertical distribution. A
beta -distribution was fitted to data describing the vertical distribution of
foliage on each tree, and the resulting parameter estimates were modelled as functions of tree height, diameter at breast
height, crown length, and relative height in the stand. Foliage area
distribution tended to be shifted downward relative to foliage mass because of
the expected increase in specific leaf area with depth into the crown.
Similarly, the relative foliage distribution in terms of both mass and area was
shifted downward as the tree became more dominant, or as relative height in the
stand increased. In contrast, foliage on trees of similar relative height was
shifted upward in response to the lower stand densities imposed by precommercial thinning. On the stand level, relative
vertical distribution of foliage in the canopy was more peaked than would be
implied by assuming a constant leaf area/sapwood area ratio throughout the
composite tree crowns. Between-stand variation in vertical foliage distribution
was dictated by differences in stand top height, height to crown base, and
number of trees per hectare.
OSU
Link
Non-OSU
Link
54. Marshall, D.D. and R.O. Curtis. 2002. Levels-of-growing-stock
cooperative study in Douglas-fir: report no. 15 - Hoskins: 1963-1998. Pacific-Northwest-Research-Station,-USDA-Forest-Service
Research-Paper PNW-RP-537. 80 p.
Keywords: thinning
commercial thinning
growth
yield
tree/stand health
tree morphology
Abstract:
The cooperative levels-of-growing-stock (LOGS) study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was begun to study the relations between
growing stock, growth, cumulative wood production, and tree size in repeatedly
thinned stands. This report summarizes results from the Hoskins installation
through age 55. Growing stock has been allowed to accumulate for 19 years since
the last treatment thinning was applied in this high site class II natural
stand. Volume and diameter growth were strongly related to growing stock. Basal
area growth-growing stock relations were considerably weaker. Differences in
tree size and volume distribution were considerable. Culmination of mean annual
increment has not occurred for any of the treatments, although the control has
culminated for total stem cubic volume and is near culmination for merchantable
cubic volume. Only small differences are seen in growth percentages between
thinning treatments. Results demonstrate potential flexibility in managing
Douglas-fir to reach a range of objectives.
OSU Link
Non-OSU Link
55. McDonald, P.M. and G.O. Fiddler. 1996. Development of a mixed
shrub-tanoak-Douglas-fir community in a treated and untreated condition. Pacific-Southwest-Research-Station, USDA-Forest-Service
Research-Paper PSW-RP-225. iv + 16 p.
Keywords: release
treatments
manual release
chemical release
tree/stand health
growth
tree morphology
stand conditions
economics
Abstract:
On a medium site in northern California, a tanoak (Lithocarpus
densiflorus)-mixed shrub community in a Douglas fir
plantation was given several treatments (manual release two and three times, a
combination chainsaw and cut surface herbicide (Garlon
3A [triclopyr]) treatment, two foliar herbicides (2,4-D or Garlon 4), and a tank mix
of the two herbicides) to study its development in both a natural (control) and
treated condition. The herbicides were each applied twice. Survival of planted
Douglas fir (Pseudotsuga menziesii)
seedlings was recorded for 11 years and growth was quantified for 9 years after
the last treatment application. In addition to Douglas fir, data are presented
individually for the two most abundant species (tanoak and snowbrush, Ceanothus velutinus var. hookeri), for greenleaf manzanita (Arctostaphylos patula), and for the hardwood tree and shrubs combined. At
the study's end in 1992, combined vegetation in the control had a mean density
of 1800 plants/acre, foliar cover of 23 700 ftsuperscript 2/acre, and height of 11.2 ft. In
contrast, combined tree and shrubs in the most effective treatment for controlling
them (cut and spray Garlon 3A) had a mean density of 150 plants/acre, foliar cover of 150 ftsuperscript
2/acre and height of 5.9 ft at study end. Because competition for site
resources was low, Douglas fir seedlings developed best in this treatment. Mean
Douglas fir diameter was 4.6 inches at 12 inches above mean ground line, height
averaged more than 21 ft, and mean foliar cover was 39 850 ftsuperscript
2 at the end of the study. The cost was $227 per acre.
OSU
Link
Non-OSU
Link
56. McDonald, P.M. and G.O. Fiddler. 1999. Ecology and development of
Douglas-fir seedlings and associated plant species in a Coast
Range plantation. Pacific-Southwest-Research-Station, USDA-Forest-Service
Research-Paper PSW-RP-243. ii + 18 p.
Keywords: release
treatments
manual release
chemical release
stand conditions
growth
tree morphology
economics
Abstract:
On an average site in northern coastal California, USA, a tanoak (Lithocarpus densiflorus)-mixed
shrub community was given several treatments (manual release one, two, and
three times; a combination chainsaw and cut surface chemical treatment; two
foliar chemicals; and a tank mix of the two chemicals) to study its development
over an 11-year period (1981-91) in both a broadcast-burned (untreated control)
and released (treated) condition. The chemicals were 2,4-D,
Garlon [triclopyr] 3A, and Garlon 4, each applied two times. The site had been planted
with 2+0 seedlings of Douglas fir (Pseudotsuga menziesii) in 1979. In addition to Douglas-fir , data are presented individually for the four most
abundant and well distributed species (tanoak, hairy manzanita
(Arctostaphylos columbiana),
huckleberries (Vaccinium ovatum
and V. parviflorum), and rhododendron (Rhododendron macrophyllum)), and for these plus two more of the tallest
and most abundant (but poorly distributed) species (snowbush (Ceanothus velutinus), elderberry
(Sambucus mexicana))
combined. In 1991, combined shrubs in the control had a mean density of 4733
plants per acre, foliar cover of 16 800 ft2 per acre, and height of 9.5 feet.
In contrast, combined shrubs in one of the most effective treatments for
controlling them (2,4-D) had a mean density of 2000 plant per acre, foliar
cover of 2600 ft2 per acre and height of 5.5 feet at the end of the study.
Here, mean Douglas-fir diameter was 4.0 inches at 12 inches above mean ground
line, height averaged 18.7 feet, and mean foliar cover was 34 800 ft2 per acre.
The cost (including chemical) was $77 per acre. The biological and economical
data in this paper provide the ecosystem manager, wildlife biologist, and fuels
manager with knowledge on how to attain plant communities with different
density and development potentials, and the cost of creating them.
OSU Link
Non-OSU Link
57. Minore, D., H.G. Weatherly and P.G.
Cunningham. 1993. Sowing at 1.5-cm (0.6-inch) depth produces heaviest
Douglas-fir roots in small containers. Tree-Planters' Notes 44(3): 122-124.
Keywords: nursery
operations
tree morphology
growth
reproduction
Abstract:
Sowing seeds of Douglas fir (Pseudotsuga menziesii) at five depths in Leach Super Cells indicated
that the only benefit of deep sowing in small containers occurred at a depth of
1.5 cm. Sowing at this depth produced heavier roots without a significant
reduction in seedling emergence. Sowing at greater depths significantly reduced
seedling emergence and growth.
OSU Link
Non-OSU
Link
58. Mitchell, S.J. 2000. Stem growth responses in Douglas-fir and Sitka
spruce following thinning: implications for assessing wind-firmness.
Forest-Ecology-and-Management 135(1/3): 105-114.
Keywords: thinning
tree morphology
carbon allocation
growth
Abstract:
Diagnosing the stand hazard component of windthrow
risk requires evaluation of the 'acclimation' of trees to wind loads.
Height-diameter ratio is a commonly used indicator of relative wind-firmness. A
sample of coastal Sitka spruce (Picea sitchensis) and interior Douglas fir (Pseudotsuga
menziesii) trees, representing a range of initial
slenderness, were sampled from stands in British Columbia, Canada, which had
very high densities (about 6000 and 23,000 stems/ha, respectively) prior to
thinning. Annual height increment, radial increment, allocation of radial
increment along the bole, and height-diameter ratio were reconstructed using
stem analysis. Thinning treatments affected growth responses compared to trees
in control (unthinned) stands: temporary reduced
height increment, increased radial increment and increased basal allocation
contributed to a reduction in height-diameter ratio. This reduction was most
pronounced in trees which were initially more slender. The reverse-S pattern of
height-diameter ratio adjustment and the patterns of growth allocation suggest
a period of acclimative growth during which the trees
re-equilibrate with post-thinning wind loads. Observing the rate of stem form
adjustment could be useful in diagnosing wind-firmness when scheduling multiple
thinning entries in high-density stands.
OSU
Link
Non-OSU
Link
59. Mohammed, G.H., K.R. Patel and W.E. Vidaver.
1989. The control of adventitious root production in tissue-cultured
Douglas-fir. Canadian-Journal-of-Forest-Research 19(10): 1322-1329.
Keywords: nursery
operations
reproduction
growth
tree morphology
Abstract:
Rooting percentage and root number in tissue-cultured Douglas fir (Pseudotsuga menziesii) were
examined to assess the influence of rooting substrate, the concentrations of
sucrose and boron in the rooting medium, shoot height, and shoot generation.
Peat/perlite was a better substrate than agar,
producing 70% compared with 0% rooted shoots, respectively. On peat/perlite, cell divisions were organized and were associated
with tracheid nests, whereas on agar proliferation
was neither organized nor restricted to the nests. An optimum sucrose
concentration of 4% was found for the production of nodular or rooted shoots.
At 4% sucrose and 3 mg/litre boric acid, 100% of the
shoots rooted, and the mean root number was 11. Rooting percentage and root
number were significantly greater with shoots that were 3 cm tall rather than 2
or 1 cm tall. Shoot responses were more rapid in third and fourth generation
shoots, with at least 80% rooted or nodular after 4 weeks, compared with only
36% from the second generation.
OSU
Link
Non-OSU
Link
60. O'-Hara, K.L. 1988. Stand structure and growing space efficiency
following thinning in an even-aged Douglas-fir stand.
Canadian-Journal-of-Forest-Research 18(7): 859-866.
Keywords: thinning
commercial thinning
growth
tree morphology
carbon allocation
Abstract:
The growth of individual trees from four thinning treatments in a
64-yr-old Pseudotsuga menziesii
stand in western Washington
was analysed to determine desirable residual stand
structures after thinning. Dominant and codominant
trees had the highest individual tree stem vol. growth rates over the previous
5 yr and accounted for most stand vol. growth in thinned and unthinned stands. Two measures of growing space, crown
projection area and sapwood b.a. (a surrogate for leaf area), were used to
measure how efficiently individual trees used their growing space. Crown
classes were useful in characterizing growing space efficiency (vol. growth per
unit of growing space) only in the unthinned
treatment. In thinned treatments, tall trees with medium-sized crowns were most
efficient, while in the unthinned treatment tall
trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized
crown in a thinned stand. Results suggest growing space is not limiting
individual tree growth in thinned stands and that thinning to a particular
stand structure is more appropriate than thinning to a particular stand
density.
OSU
Link
Non-OSU
Link
61. O'-Hara, K.L. 1989. Stand growth efficiency in a Douglas fir
thinning trial. Forestry-Oxford 62(4): 409-418.
Keywords: thinning
commercial thinning
growth
carbon allocation
tree morphology
Abstract:
Stand growth efficiency (ratio of periodic stand volume growth to sapwood basal
area) was measured over 5 yr (1980-84) in a long term Douglas fir (Pseudotsuga menziesii) thinning
trial (established in 1957 at 36-yr-old, with 5 thinnings
over 23 yr) in coastal Washington,
USA.
Sapwood basal area - as a surrogate for leaf area - and volume growth were
estimated in two fifth-hectare plots from each of three thinning treatments,
and from a single fifth-hectare control plot. Stand growth increased with
increasing sapwood basal area. No distinct pattern of stand growth efficiency
with sapwood basal area was evident. Large differences in efficiency between
plots of the same treatment were found and were attributed to differences in
stand structure, or the arrangement of tree sizes.
OSU
Link
Non-OSU
Link
62. Perry, D.A., C. Choquette and P.
Schroeder. 1987. Nitrogen dynamics in conifer-dominated forests with and
without hardwoods. Canadian-Journal-of-Forest-Research 17(11): 1434-1441.
Keywords: release
treatments
soil properties
tree morphology
Abstract:
In studies on the E. slopes of the Oregon Coast Range, contents of N and
C in the surface 12 cm of mineral soil, N in leaf litterfall,
anaerobic N mineralization rates in the soil and forest floor, and root and N
accretion to sand traps placed in surface soil layers were studied in stands
dominated by Douglas fir trees, from which the broadleaved component had been
partially or completely removed during thinning 3 yr earlier. Contrary to
expectations, stands without broadleaved species had more N in mineral soil, a
greater rate of anaerobic soil N mineralization and a lower soil C : N ratio than stands with broadleaved species. These
variables did not differ between thinned and unthinned
mixed stands. From litterfall and sand trap data, it
is suggested that N was redistributed in the coniferous system after removal of
the broadleaved species.
OSU
Link
Non-OSU
Link
63. Peterson, M. and J.R. Sutherland. 1989. Grey mould control by
seedling canopy humidity reduction through under-bench ventilation and styroblock aeration. B.C.
Ministry of Forests FRDA-Report 077. 15 p.
Keywords: nursery
operations
growth
tree/stand health
tree morphology
Abstract:
The potential for grey mould control on Douglas-fir seedlings was investigated
using under-bench ventilation and aerated styroblocks.
Twenty-five percent of all ventilated styroblock
seedlings were infected with Botrytis cinerea while
75% of the control seedlings showed signs of infection. The reduced incidence
of grey mould in the ventilated treatments was attributed to a more rapid
drying of the seedling canopy following watering. The lowest frequency of ideal
conditions for B. cinerea infection by spore
germination was observed in the seedling canopy of the treatment receiving
unheated, forced air ventilation.
OSU Link
Non-OSU Link
64. Reukema, D.L. and J.H.G. Smith. 1987.
Development over 25 years of Douglas-fir, western hemlock, and western redcedar planted at various spacings
on a very good site in British
Columbia. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-381.
ii + 46 p.
Keywords: planting
operations
pruning
growth
yield
tree morphology
Abstract:
Five spacing trials were established during 1957-67 at the University of British Columbia Research Forest, covering a range of spacings from 1 to 5 m and of experimental designs
(49-tree-plot, 0.2-ha plot, rectangularity, Nelder
and variable block trials). Results showed that initial spacing is among the
most important factors influencing stem and crown development, and stand growth
and yield for Douglas fir (Pseudotsuga menziesii), western hemlock (Tsuga
heterophylla) and western redcedar
(Thuja plicata). Top
heights were initially taller at closer spacings, but
are now similar at all spacings. Av. ht. is now
shorter at close spacing. Decreases in heights to dead and live crowns and
increases in diam. of lower stem, taper and crown
size occurred as spacing increased. B.a.
and stand vol. increased as spacing decreased until onset of density-related
mortality. It is concluded that initial wide spacings
with rectangularities up to 2:1 (e.g. 6x3 m) will
result in efficient production of large trees of high value and satisfactory
quality. Pruning of widely spaced trees to enhance lower stem quality is
strongly recommended.
OSU Link
Non-OSU Link
65. Ritchie, G.A., J.W. Keeley and P.A.
Ward. 1997. Effects of shade and root confinement on the expression of plagiotropic growth in juvenile-origin Douglas-fir rooted
cuttings. Canadian-Journal-of-Forest-Research 27(7): 1142-1145.
Keywords: nursery
operations
growth
tree morphology
Abstract:
The purpose of this experiment was to determine why juvenile-origin Douglas fir
(Pseudotsuga menziesii)
rooted cuttings, which remain plagiotropic
(branch-like) when grown in containers in shaded greenhouses, become orthotropic
(vertical) after they are transplanted to an outdoor environment. Plagiotropic rooted cuttings (mean angle from vertical =
45-50 degrees ) from three full-sib families were transplanted into an outdoor
nursery in Olympia, Washington, and subjected to four treatments consisting of
a factorial of (1) shaded or unshaded and (2) bareroot or confined roots. After two growing seasons,
treatments had significantly affected plant size and biomass in the order unshaded-bareroot > shaded-bareroot
> unshaded-confined > shaded-confined, but
plants in all treatments had become nearly orthotropic. It is concluded that
neither shading nor root confinement is, but other greenhouse environmental
conditions are, responsible for the persistence of plagiotropic
growth.
OSU
Link
Non-OSU
Link
66. Ritchie, G.A., Y. Tanaka and S.D. Duke. 1992. Physiology and
morphology of Douglas-fir rooted cuttings compared to seedlings and
transplants. Tree-Physiology 10(2): 179-194.
Keywords: nursery
operations
tree phenology
tree physiology
growth
tree morphology
carbon allocation
Abstract:
Cuttings of Douglas fir (Pseudotsuga menziesii) from three open-pollinated families were rooted
in two types of tray and then grown for 1.5 years in a nursery in Washington
State. During their second winter
they were sampled periodically and tested for cold hardiness, dormancy status,
root growth potential and various morphological characteristics. Two-year-old
seedlings and transplants were tested concurrently for comparison. Rooted
cuttings, seedlings and transplants cold hardened at similar rates during early
winter, achieving the same level of midwinter hardiness (LT50 = -18 degrees C)
in early January. However, rooted cuttings remained hardier later into spring
than did seedlings or transplants. Rooted cuttings exhibited deeper dormancy in
early winter than seedlings or transplants but these differences disappeared
after January. Root growth potentials of all three stock types remained above
threshold values established for transplants throughout winter. Rooted cuttings
had greater stem diameter, higher stem diameter
: height ratio, and greater root weight than either seedlings or
transplants. This may reflect lower growing densities for rooted cuttings. Root : shoot ratios of rooted
cuttings were greater than for seedlings and similar to those of transplants.
Rooted cuttings also had deeper and coarser root systems, which probably
reflected lack of wrenching at the nursery.
OSU
Link
Non-OSU
Link
67. Rose, R., J.F. Gleason and M. Atkinson. 1993. Morphological and
water-stress characteristics of three Douglas-fir stocktypes
in relation to seedling performance under different soil moisture conditions.
New-Forests 7(1): 1-17.
Keywords: nursery
operations
tree phenology
tree physiology
growth
tree morphology
Abstract:
Phenology, morphology, frost hardiness and response
to moisture stress were examined for three Douglas fir (Pseudotsuga
menziesii) stocktypes grown
from the same seed lot in a nursery near Olympia,
Washington, USA.
The types were mini-plugReg. transplants (MPT), 1+1 bareroot
transplants (1+1), and 2+0 bareroot seedlings (2+0).
In the late summer and autumn before lifting, 2+0 seedlings set bud before 1+1
seedlings and 1+1 seedlings before MPT seedlings. The 2+0 seedlings appeared
slowest to acquire frost hardiness and seemed to deharden
most rapidly in spring. Although 2+0 seedlings were taller than the MPT stocktype, MPT and 2+0 seedlings were relatively similar in
other morphological respects, but 1+1 seedlings were much larger. All stocktypes were potted on 20 January 1989, placed in
a greenhouse, and subjected to 39%, 18%, 16%, or 6% soil water-content (% dry
weight) until the end of the experiment in mid-July 1990. The largest decrease
in pre-dawn xylem water potential occurred with 16% and 6% soil water content;
pre-dawn xylem water potential averaged over the three stocktypes
generally declined 219% from low to high soil moisture stress. The 1+1
seedlings used more water than the other two stocktypes,
and at maximum soil moisture stress, plant moisture stress increased in the
order MPT < 2+0 < 1+1. During the 6-month greenhouse experiment, the
larger 1+1 stocktype showed the most absolute growth,
but the smaller stocktypes grew more on a relative
scale. Growth of the stocktypes appeared to be
related to differences in morphology and water-use patterns as the seedlings
competed for available water within each pot. The results show that MPT
seedlings, a new stocktype, performed as well as the
more traditionally used 2+0 and 1+1 seedlings and that stocktype
selection is important in reforestation efforts.
OSU
Link
Non-OSU Link
68. Rose, R. and D.L. Haase. 2000. The use
of coir as a containerized growing medium for Douglas-fir seedlings.
Native-Plants-Journal 1(2): 107-111.
Keywords: nursery
operations
growth
carbon allocation
tree physiology
tree morphology
soil properties
Abstract:
In response to environmental concerns and the need for peatland conservation, alternative growing media for
conifer seedling production must be investigated. Douglas-fir (Pseudotsuga menziesii) seedlings
were grown in 6 media; components included peat moss, peat moss amended with
sawdust, and 2 sources of coir (coconut fibre) mixed
with and without peat moss. Coir had higher pH, P, K, and Na and lower Ca and N
than peat moss and a peat moss-sawdust mixture. Bulk densities of coir and
coir-based media were lower than those in peat moss and a peat moss-sawdust
mixture. After 21 weeks, seedlings grown in coir-based media were significantly
smaller and had lower foliar N and Ca than those grown in peat moss. Because of
coir' many favourable qualities, further research is
recommended using culturing regimes specific to the substrate's nutrient
properties.
OSU
Link
Non-OSU
Link
69. Rose, R., J.S. Ketchum and D.E. Hanson. 1999. Three-year survival
and growth of Douglas-fir seedlings under various vegetation-free regimes.
Forest-Science 45(1): 117-126.
Keywords: release
treatments
chemical release
growth
tree morphology
tree/stand health
stand conditions
Abstract:
Responses of Douglas-fir (Pseudotsuga menziesii) seedlings were studied for 3 yr (1993-96)
following eight vegetation-control treatments in three western Oregon
clearcuts. The objectives were to determine seedling
growth response to different areas of spot vegetation control and to determine
the relative influence of early woody and herbaceous competition on seedling
growth. Herbicide treatment areas varied in size from those receiving no
control to full control (9.3 msuperscript 2).
Controlled areas were maintained free of herbaceous vegetation for 2 yr and all
woody vegetation was controlled for 3 yr. Two additional treatments, complete
control of woody vegetation only and complete control of herbaceous vegetation
only, were also examined. On two sites (Summit
and Marcola), seedling growth parameters were
maximized at or near full vegetation control with a tree spacing of 3 m x 3 m.
On the third site (Pedee), maximum growth response
occurred between 5 and 6 msuperscript 2 of control.
Herbaceous vegetation control resulted in increased seedling growth at all
sites while woody vegetation control yielded increased seedling growth only at
the Pedee site. Cumulative 3 yr herbaceous cover
accounted for 68% and 41% of the variability in stem volume at Summit
and Marcola, respectively. Adding cumulative 3 yr
woody cover to the model accounted for an additional 18% and 49% of the
variability in stem volume at Summit
and Marcola, respectively. At Pedee,
neither herbaceous nor woody cover significantly influenced 3 yr stem volume,
suggesting that factors other than vegetation cover were responsible for
differences measured.
OSU
Link
Non-OSU Link
70. Roth, B.E. and M. Newton. 1996b. Survival and
growth of Douglas-fir relating to weeding, fertilization, and seed source.
Western-Journal-of-Applied-Forestry 11(2): 62-69.
Keywords: planting
operations
fertilization
release treatments
chemical release
growth
tree physiology
tree morphology
tree/stand health
Abstract:
The goal of this study was to quantitatively evaluate the individual
and interactive effects of weed control, nitrogen fertilizer, and seed source
on Douglas fir (Pseudotsuga menziesii)
survival and growth in plantations on a range of sites and growing conditions
in western Oregon.
Weed control with hexazinone (broadcast application
after planting) was the dominant factor influencing seedling survival and
growth and accounted for 49% of the explained variation in seedling volume
after 2 years. Nitrogen fertilizer (urea) had no effect when used in
conjunction with weed control and a negative effect when used without weed
control. Seedlings from a seed orchard source were significantly larger in
diameter and volume than those from a wild local source after two growing
seasons, but second-year heights were similar for the two seedling types.
Initial seedling size was positively correlated with growth rate.
OSU
Link
Non-OSU Link
71. Scagel, C.F., R.G. Linderman
and R.K. Scagel. 2000. Ten-year growth and survival of Douglas-fir seedlings
treated with plant growth regulating substances at transplant. Canadian-Journal-of-Forest-Research
30(11): 1778-1787.
Keywords: nursery
operations
growth
tree/stand health
tree morphology
Abstract:
Commercially available plant growth regulators (PGRs)
or moisture retention gels, applied to the roots of Douglas fir (Pseudotsuga menziesii) before
planting, can modify IAA levels in roots, root growth responses, and tree
survival. Two different 1+0 stock types (PSB313B and PSB323, interior and
coastal Douglas fir,
respectively, the latter having a larger root mass) were treated with IBA, ethephon (Ethrel), alginate, or a
combination of IBA and alginate. New root growth and IAA levels in roots were
measured 2 weeks after planting, and aboveground growth and tree survival were
monitored over 10 growing seasons after planting in May 1988 on a site clear
felled in winter 1988 in British Columbia, Canada; no site preparation was
carried out. Treatment with IBA or the combination of IBA and alginate
increased IAA conjugate and free IAA levels in roots, root growth, and tree survival.
Alginate treatment alone increased new root growth and tree survival, but did
not increase free IAA levels in roots. Ethephon
treatment increased free IAA levels and root growth, but had no effect on IAA
conjugates or tree survival. A cost analysis suggested that use of certain PGRs or alginate decreased the cost required to attain
target stocking and increased tree size. The results suggest that application
of PGRs or other root-promoting materials to the
roots of Douglas fir before planting has the potential to be a cost-beneficial
method for increasing root growth and tree survival.
OSU
Link
Non-OSU
Link
72. Schneider, W.G., S.A. Knowe and T.B.
Harrington. 1998. Predicting survival of planted Douglas-fir and ponderosa pine
seedlings on dry, low-elevation sites in southwestern Oregon.
New-Forests 15(2): 139-159.
Keywords: site
preparation
mechanical preparation
prescribed fire
tree/stand health
tree morphology
stand conditions
Abstract:
Four equations were developed by logistic regression for predicting
the probability of Douglas fir (Pseudotsuga menziesii) and ponderosa pine (Pinus
ponderosa) survival for the first (0-1) and first to third (1-3) growing
seasons after applying mulching, radial scalping (removal of all vegetation and
a thin layer of soil in a 1-m radius area around each tree), or artificial
shading (shade cards) treatments in plantations in SW Oregon. Most of the sites
had been burned by wildfire or prescribed fire before planting. Variables
describing conifer size, levels of competing vegetation, presence of silvicultural treatments, site factors, and climate factors
were collected from 13 sites up to 6 yr after planting and examined as
potential predictors of survival. Age, stem diameter, a competition index for
shrubs, severity of growing season at time of treatment, average annual
precipitation, aspect, and slope angle were predictors of Douglas fir survival
during 0-1 and 1-3 growing seasons after treatment; the presence of silvicultural treatments was also a predictor only during
the first growing season after treatment. Age, aspect, and slope angle were
predictors of ponderosa pine survival over both 0-1 and 1-3 growing seasons
after treatment; height-diameter ratio, competition indices for herbs, shrubs,
and hardwoods, silvicultural treatment, severity of
growing season at time of treatment, and average annual precipitation were also
predictors only during the first growing season after treatment; crown width
was a predictor of survival only during 1-3 growing seasons after treatment.
When significant in the models (equations), predicted probability of survival
increases with treatments, less severe weather conditions, diameter, crown
width, age, and precipitation; probability decreases with increasing
height-diameter ratio and competition indices for herbs, shrubs, and hardwoods.
OSU Link
Non-OSU Link
73. Shainsky, L.J., M. Newton and S.R. Radosevich. 1992. Effects of intra- and inter-specific
competition on root and shoot biomass of young Douglas-fir and red alder.
Canadian-Journal-of-Forest-Research 22(1): 101-110.
Keywords: planting
operations
growth
tree morphology
carbon allocation
tree physiology
Abstract:
Two-year-old seedlings of Douglas fir (Pseudotsuga
menziesii) and red alder (Alnus
rubra) were planted in Oregon in 1985 at densities of
1, 2, 4, 8 and 16 trees/msuperscript 2 in a two-way
density matrix composed of 5 monoculture densities and 25 mixtures of all
possible pairwise combinations of monoculture
densities. Roots and shoots were harvested after the fourth growing season.
Response surfaces for root, shoot and total biomass per tree were generated within
the matrix. Regression analysis quantified the effect of each species' density
on biomass components. Alder overtopped the Douglas fir in all mixed stands.
Alder density influenced the root and shoot biomass of both species more than
Douglas fir density did, the greatest reduction in root biomass of Douglas fir
taking place at an alder density of <less or =>1 tree/msuperscript
2. Douglas fir density interacted with red alder density to influence all
biomass components. Douglas fir density effects were inconsistently significant
across alder densities. While increasing the density of each species reduced
root and shoot biomass per tree, allocation of biomass to roots and shoot was
not affected by competition, nor were the allometric
equations relating biomass to stem diameter and stem volume index. Foliar
concentrations of N and P in the Douglas fir understorey
are reported.
OSU
Link
Non-OSU
Link
74. Sorensen, F.C. 1997. Effects of sib mating and wind pollination on
nursery seedling size, growth components, and phenology
of Douglas-fir seed-orchard progenies. Canadian-Journal-of-Forest-Research
27(4): 557-566.
Keywords: genetic
tree improvement
nursery operations
growth
tree/stand health
tree morphology
tree phenology
Abstract:
Polymix outcross (X), full-sib (FS), and wind-pollination (WP)
families were produced on 25 seed trees and 10 half-sib families on 10 of the
same trees in a Pseudotsuga menziesii
var. menziesii seedling seed orchard in Oregon.
Seedlings were raised at 2 sowing densities for 2 years in the nursery, and
inbreeding depression (ID) in seedling size related to inbreeding effect on
growing season length and growth rate. Seedling mortality was light and not
affected by inbreeding. Mean ID for 2-year size traits was 6% (height) and
about 8% (diameter) per 10% increase in F, the inbreeding coefficient, and was
linear with the increase in F over the range of F used. Both amount of ID and
its fit to linearity differed greatly among seed trees. Elongation season was significantly
and slightly shorter for FS than for X families; second-year relative
elongation rate was nonsignificantly larger for FS
than for X families. Inbred families had nonsignificantly
larger within-plot variance and significantly larger coefficients of
within-plot variance than X families. Sowing density was not a significant
factor except in diameter and height/diameter ratio. Results are discussed in
terms of plant growth habit and possible gene action. WP compared with X
families were significantly shorter by 3.8% and significantly smaller in
diameter by 4.6%, with much variation among family groups. About half of the
height difference could be explained by seed weight; the remainder could have
been due to pollen contamination or natural inbreeding. Progenies of the two
pollen types did not differ for phenological traits,
even though the seed orchard was in a drier, more inland location than the
parent-tree locations. Progenies of WP had nonsignificantly
larger within-plot variance than X progenies.
OSU
Link
Non-OSU Link
75. St-Clair, J.B. 1994b. Genetic variation in tree
structure and its relation to size in Douglas-fir. II. Crown form,
branch characters, and foliage characters. Canadian-Journal-of-Forest-Research
24(6): 1236-1247.
Keywords: genetic
tree improvement
carbon allocation
tree morphology
wood quality
genetic relationships
Abstract:
Genetic variation and covariation among traits of
tree size (volume, basal area, diameter at breast height and height) and
structure were assessed in 1991 in an 18-year-old Douglas fir (Pseudotsuga menziesii var. menziesii) genetic test in the Coast Range of Oregon.
Considerable genetic variation was found for relative crown width, stem
increment per crown projection area, leaf area and branch weight relative to
crown size, branch diameter and length adjusted for stem size, branch
stoutness, cross-sectional area of branches per crown length and needle size.
Little genetic variation was found for branch numbers per whorl, branch angle
and specific leaf area. At both the phenotypic and genetic level, large trees
growing in relatively small spaces had tall, narrow crowns, high leaf areas per
crown projection area or branch length, greater partitioning to leaves versus
branches, and stouter branches. Thus, large, efficient trees were those that
invested more in the photosynthetic machinery of leaf area and the branch
biomass necessary to support that leaf area, but distributed that leaf area
over a greater vertical distance. Unfortunately, these traits were also
associated with increased branchiness, and selection
for these traits would be accompanied by reductions in harvest index and wood
quality.
OSU
Link
Non-OSU
Link
76. St-Clair, J.B. and R.A. Sniezko. 1999.
Genetic variation in response to shade in coastal Douglas-fir.
Canadian-Journal-of-Forest-Research 29(11): 1751-1763.
Keywords: genetic
tree improvement
growth
tree morphology
carbon allocation
tree phenology
Abstract:
Tree improvement programmes have generally
relied on testing families in open light environments. With increased interest
in multiaged silvicultural
systems, some people have questioned whether families selected in the open are
appropriate for planting in the shade. Douglas-fir (Pseudotsuga
menziesii var. menziesii)
families from two climatically distinct seed sources in the Coast
Range (NW Oregon)
and Siskiyou
Mountains (SW
Oregon) were grown for 2 years under four levels of shade. The
response to shade differed for several traits between the two populations and
among families within populations. The magnitude of variation associated with
the interaction, however, was small compared with the overall effects of
genetic selection or of shade. Families selected based
on performance in an open light environment resulted in nearly the same
response to selection when grown under shade as families selected based on
performance in the shade. It is concluded that seedlings from families selected
in an open light environment are appropriate for use in the low-light
environments of alternative silvicultural systems and
that use of such genetically selected stock may compensate for the less favourable growing conditions. Genetic selection may
contribute importantly to meeting multiple objectives, including the production
of significant amounts of wood as well as the efficient and timely creation of
large stand structures needed for other forest values.
OSU
Link
Non-OSU
Link
77. Stein, W.I. 1984. Wrenching Douglas-fir seedlings in August:
immediate but no lasting effects. Pacific-Northwest-Forest-and-Range-Experiment-Station,-USDA-Forest-Service
Research-Paper PNW-RP-317. 12
p.
Keywords: nursery
operations
tree morphology
growth
carbon allocation
tree/stand health
Abstract:
Seedlings in a nursery in Oregon
were wrenched in their 2nd growth season in 1976. Wrenched and unwrenched seedlings were sampled at intervals from Aug.
1976 until Jan. 1977, and measured. The entire bed was lifted in Jan. and 100
treated and 100 control seedlings were planted out. After 24 days (Aug.), the
number of lateral roots, shoot length, and root dry wt. were significantly
smaller in wrenched seedlings. Shoot/root ratio was also smaller and remained
so until early Oct. By late Oct., shoot length and the number of lateral roots
were significantly greater in wrenched seedlings. During the first 5 yr after
planting out, there were n.s.d. between wrenched and unwrenched trees in survival and growth, which were both
good.
OSU Link
Non-OSU Link
78. Stein, W.I. 1988. Nursery practices, seedling sizes, and field
performance. In: Proceedings, combined meeting of the Western Forest
Nursery Associations; 1988 August 8-11; Vernon,
British Columbia.
Tech Coord. T.D.
Landis. Rocky Mountain Forest and Range Experiment Station, USDA Forest Service General Technical Report RM-GTR-167.
15-18 pp.
Keywords: nursery
operations
growth
tree morphology
tree/stand health
Abstract:
Highlights are presented from a large cooperative study in Oregon
to determine the combined effects of nursery cultural practices on the size and
field performance of 2+0 Douglas fir [Pseudotsuga menziesii] seedlings. Seedlings were grown in 3 nurseries
using seed from 7 sources; field plantings were made over 3 yr on 28 sites in SW
Oregon. Seedbed density had more effect than
irrigation frequency, undercutting or wrenching on seedling size, and survival
and growth 4 yr after planting.
OSU Link
Non-OSU Link
79. Steinfeld, D., D. Davis, S. Feigner and
K. House. 2002. Fall versus spring transplanting of container seedlings: a
comparison of seedling morphology. In National
Proceedings: Forest and
Conservation Nursery Associations 1999, 2000, and 2001, USDA-Forest-Service
Rocky-Mountain-Research-Station RMRS-P-24. 196-200
pp.
Keywords: nursery
operations
growth
tree/stand health
tree morphology
Abstract:
In a study in Oregon,
USA,
containerized seedlings of Engelmann spruce (Picea engelmannii), sugar pine (Pinus lambertiana), Douglas-fir (Pseudotsuga
menziesii), western redcedar
(Thuja plicata), and western
hemlock (Tsuga heterophylla)
transplanted in the early fall and later in the early spring were compared for
differences in stem diameter, height, root area, and shoot area.
Fall-transplanted Pseudotsuga menziesii
and the Thuja plicata
showed an increase in stem diameter of 13 (2.0 mm) and 4% (0.4 mm),
respectively. Fall-transplanted seedlings developed larger root systems - Picea engelmannii by 18%, Pinus lambertiana by 48%, Pseudotsuga menziesii by 58%, and
Tsuga heterophylla by 47%.
Non-OSU
Link
80. Thompson, G. 1995. Nitrogen fertilization requirements of
Douglas-fir container seedlings vary by seed source. Tree-Planters' Notes
46(1): 15-18.
Keywords: nursery
operations
nursery fertilization
growth
carbon allocation
tree morphology
Abstract:
Growth of container-grown Douglas fir (Pseudotsuga
menziesii) from different seed sources from western Washington,
northern Idaho
and western Montana
was evaluated following application of 100, 150, or 200 p.p.m.
nitrogen during the rapid growth phase. The optimum level of N varied between
seed sources for height, stem diameter, and bud growth, as well as for root
shoot ratio. Target seedling specifications were met adequately for the
westernmost sources at 100 and 150 p.p.m. N, whereas
eastern sources required 150 or 200 p.p.m. Nitrogen
levels should thus be tailored to individual Douglas fir seed sources to
maximize the number of shippable seedlings per lot.
OSU Link
Non-OSU
Link
81. Thomson, A.J. and H.J. Barclay. 1984. Effects of thinning and urea
fertilization on the distribution of area increment along the boles of
Douglas-fir at Shawnigan Lake, British
Columbia.
Canadian-Journal-of-Forest-Research 14(6): 879-884.
Keywords: fertilization
thinning
tree morphology
growth
Abstract:
Assessments were made using radial growth measurements made 6 and 9 yr
after treatment. Within treatments, av. area increment per tree was linearly
related to d.b.h. and this relation was used to
evaluate the effects of treatment on growth rate. Fertilizing had the greatest
effect on av. area increment, and for a particular fertilization regime,
thinning increased the response. Thinning modified the distribution of growth
over the bole of all trees and increased butt flare, especially in smaller
trees. The effect declined from the 4- to 6-yr measurement period to the 7- to
9-yr measurement period. Fertilizing had no consistent effect on growth
distribution. The regression methods used in this study provided a more
sensitive measure of form changes than previous methods, were independent of
size distribution, and facilitated extrapolations and evaluation of temporal
trends.
OSU
Link
Non-OSU
Link
82. Turner, J. and S.J. Mitchell. 2003. The effect of short day
treatments on containerized Douglas-fir morphology, physiology and phenology. New-Forests 26(3): 279-295.
Keywords: nursery
operations
growth
tree morphology
tree physiology
photosynthesis
tree phenology
Abstract:
The effect of short day treatments ('blackout') on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
container seedlings at the time of lift and following cold storage was
investigated. Variables measured included height, root collar diameter (RCD),
root growth capacity (RGC), photosynthetic efficiency after -18 degrees C
freezing (PEF), and days to terminal bud break (DBB). From one to four blackout
dormancy induction treatments were started on three dates (July 12, July 26,
and August 10) with 10 or 20 d between multiple blackouts. Increasing the
number of blackout treatments resulted in lower RCD, lower DBB in the late
winter/early spring, and
higher PEF in the early fall. Later blackout start dates decreased PEF in the
early fall, and increased overall height and late fall RGC as compared to earlier
blackout start dates. Nurseries growing Douglas-fir seedlings from coastal Pacific
Northwest provenances should be aware that blackout
regimes can decrease RGC in the late fall, and cause quicker dormancy release
in the early spring. Coastal Douglas-fir can be lifted and planted in the early
fall, when RGC and DBB are relatively high. If planting between February and
April is necessary, seedlings given blackout should be cold stored in January
to maintain an adequate level of dormancy, RGC and PEF.
OSU Link
Non-OSU Link
83. Velazquez-Martinez, A., D.A. Perry and T.E. Bell. 1992. Response
of aboveground biomass increment, growth efficiency, and foliar nutrients to
thinning, fertilization, and pruning in young Douglas-fir plantations in the
central Oregon Cascades. Canadian-Journal-of-Forest-Research 22(9): 1278-1289.
Keywords: fertilization
thinning
pruning
growth
carbon allocation
tree physiology
tree morphology
Abstract:
The effect of thinning and silvicultural practices (multinutrient fertilization and/or pruning) on total
aboveground biomass increment and growth efficiency was studied over three
consecutive 2-year periods (1981-1987) in young Douglas fir (Pseudotsuga menziesii)
plantations in the central Oregon Cascades. Plantations were 21-27 yr old in
1987. Plots were heavily thinned (leaving 300 trees/ha), moderately thinned
(leaving 604 trees/ha) or left unthinned (leaving
3459 trees/ha) in 1981. Fertilizer (N, P, K, Ca, S and Fe) was applied with
slow-release tabs. Net above-ground biomass annual increment over the 6-year
period averaged 14.5, 7.8, and 5.5 t/ha for the high-, medium-, and low-density
plots, respectively. Growth efficiency, after dropping sharply between leaf
area indexes (LAI) of 1 and 6 msuperscript
2/msuperscript 2, remained relatively constant up to the highest measured LAI
of 17. Consequently, above-ground biomass increment continued to increase at LAIs well above that at which the Beer-Lambert law predicts
maximum light should be absorbed. Foliage analyses indicated that thinning
improved N, K and Mg nutrition and increased the translocation of K from
1-yr-old foliage to support new growth. However, fertilizer application
increased foliar N and P contents only when coupled with pruning, suggesting
that trees favour total leaf area over individual
needle nutrition. Indications of K and Mg limitations in this study are
supported by other recent studies of Douglas fir.
OSU
Link
Non-OSU
Link
84. Vogt, K.A., D.J. Vogt, E.E. Moore, W. Littke,
C.C. Grier and L. Leney. 1985. Estimating Douglas-fir
fine root biomass and production from living bark and starch.
Canadian-Journal-of-Forest-Research 15(1): 177-179.
Keywords: fertilization
tree morphology
tree physiology
Abstract:
A potential indirect technique for determining fine root biomass and
production is reported. Data from 4 permanent Douglas fir plots in Washington
State
given different fertilizer treatments showed a direct correlation between the
starch content of a 1-cm wide band of living bark at b.h.
per hectare and fine root biomass per hectare (rsuperscript
2 = 0.85). Starch content was determined in bark samples from 5 trees in each
plot and estimates of the volume of 1-cm wide bands of bark at b.h. were made from measurements of d.b.h.
and total bark thickness of every tree in each plot. Fine root biomass was
determined in soil cores obtained with a post hole digger (inner diam.
15.3 cm); traditional small core methods could not be used because of the high
gravel and rock content of the soil.
OSU
Link
Non-OSU
Link
85. Wagner, R.G. and S.R. Radosevich. 1991a.
Interspecific
competition and other factors influencing the performance of Douglas-fir
saplings in the Oregon
Coast Range.
Canadian-Journal-of-Forest-Research 21(6): 829-835.
Keywords: site
preparation
prescribed fire
growth
tree morphology
Abstract:
Regression models describing total height, stem diameter, stem volume
index, and crown volume index of individual 4- to 9-year-old saplings of
Douglas fir (Pseudotsuga menziesii)
were developed from a retrospective analysis of two site preparation
experiments (with/without prescribed burning). Measurements of 787 Douglas fir
saplings were taken at nine sites during July and August 1984. The variables
included in the models were age, interspecific competition
index, height, animal damage (browsing and clipping), use of prescribed
burning, and slope angle and azimuth. The models, which integrate environmental
and morphological factors that can influence the performance of Douglas fir
saplings into one set of equations, accounted for 64-73% of the variation in
individual tree size. Interspecific competition and
amount of animal damage were negatively correlated with tree size. Tree age,
1st-year height, and the use of prescribed burning were positively correlated
with tree size. When factors were held constant, trees were largest on steep
southeast slopes. The models indicated that tree age, competing vegetation,
animal damage, and initial seedling size had a dominant influence on the
performance of Douglas fir saplings, while prescribed burning and topography
were of relatively minor importance.
OSU
Link
Non-OSU
Link
86. Walker,
R.B., S.P. Gessel and R.E. Miller. 1994. Greenhouse
and laboratory evaluation of two soils derived from volcanic ash.
Northwest-Science 68(4): 250-258.
Keywords: fertilization
growth
tree/stand health
carbon allocation
tree morphology
tree physiology
Abstract:
This study assessed the mineral nutrient status of two soils derived
from volcanic ash in SW Oregon.
The study was initiated because conifers in some of the field plots on such
soils had failed to give an expected yield response to the application of
nitrogen fertilizer. Soil pot tests were carried out using both Romaine lettuce
(Lactuca sativa) and Douglas fir (Pseudotsuga
menziesii) seedlings, with a wide range of fertilizer
treatments. Heavy phosphorus fertilization was necessary for satisfactory
growth of lettuce, which also showed a 26% response to sulfur addition. With
Douglas fir, pot tests showed no response to nitrogen alone, but gave a
statistically significant response to phosphorus fertilization together with
nitrogen (seedlings were non-mycorrhizal), and some
suppression of yield with sulfur additions. There was a favourable
effect of sulfur fertilization on foliar colour, and
a chlorosis in younger foliage probably attributable
to iron deficiency. Most of the tissue analyses showed low concentrations of
magnesium (<0.05%), and also of calcium (<less or =>0.08%), iron
(<70 mg/kg), boron (mostly 20 mg/kg) and copper (<less or =>2.6 mg/kg)
in the younger foliage. Thus there is an implication from the field trials, and
evidence from the greenhouse and laboratory study, that elements besides
nitrogen need to be added to provide proper nutrition on these volcanic ash
soils. The information can aid in guiding further fertilizer trials in forests
on volcanic ash derived soil in SW Oregon and
elsewhere.
OSU
Link
Non-OSU
Link
87. Wilson,
J.S. and P.J. Baker. 2001. Flexibility in forest management: managing
uncertainty in Douglas-fir forests of the Pacific Northwest.
Forest-Ecology-and-Management 145(3): 219-227.
Keywords: planting
operations
thinning
yield
tree morphology
economics
tree/stand health
Abstract:
Long planning horizons generate substantial uncertainty in forest
management, making management flexibility, the ability to choose between multiple
options or opportunities, a desirable attribute of managed forests. Flexibility
in forest management reflects both the relative rigidity of intervention
requirements and the potential range of development pathways for a stand. The
wind stability of Pacific Northwest
Douglas-fir (Pseudotsuga menziesii)
plantations is used to demonstrate the concept of management flexibility. Dense
Douglas-fir plantations develop high height to diameter ratios in the dominant
trees making them unstable and prone to wind damage. The management of these
plantations is inflexible, because without early and timely thinning, the
stands do not contain stable trees that could be expected to survive long
rotations or late thinnings. A combination of reduced
planting densities and site-specific management reduces both the necessity and
rigidity of intervention requirements (e.g., thinning) and expands the number
of potential developmental pathways for these stands. The cost of greater
management flexibility is reduced efficiency of wood volume production;
however, greater adaptability to changing markets, labour
conditions, and management objectives may be more important for many forest
owners. While this approach to management is complex, it frees owners and
managers from rigid management requirements and allows for a wider range of
future stand conditions.
OSU
Link
Non-OSU
Link
88. Wilson,
J.S. and C.D. Oliver. 2000. Stability and density management in Douglas-fir
plantations. Canadian-Journal-of-Forest-Research 30(6): 910-920.
Keywords: planting
operations
thinning
tree/stand protection
tree morphology
tree/stand health
Abstract:
Limited tree size variation in Douglas fir (Pseudotsuga
menziesii) plantations in coastal Oregon,
Washington,
and British Columbia
makes them susceptible to developing high height to diameter ratios (H/D) in
the dominant trees. The H/D of a tree is a relative measure of stability under
wind and snow loads. Experimental plot data from three large studies were used
to evaluate the impact of initial planting densities and thinning on plantation
H/D values. The H/D predictions from the experimental plot data match spacing
trial results closely but are substantially different from distance-independent
growth model predictions. The results suggest that plantation H/D values can be
lowered and stability promoted through reduced planting densities or early
thinning; however, later thinnings may not be
effective in promoting stability, since they do not appear to lower H/D values.
Higher initial planting densities shorten the time period during which thinning
can be expected to effectively lower future H/D values. Time-sensitive thinning
requirements in dense plantations make their management inflexible. The
flexibility with which a stand can be managed describes the rigidity of
intervention requirements and/or potential range of stand development pathways.
OSU
Link
Non-OSU
Link