1. Amaranthus, M.P., C.Y. Li and
D.A. Perry. 1990. Influence of vegetation type and madrone
soil inoculum on associative nitrogen fixation in
Douglas-fir rhizospheres.
Canadian-Journal-of-Forest-Research 20(3): 368-371.
Keywords: planting operations
soil properties
Abstract: In
studies in SW Oregon in 1985, Douglas fir (Pseudotsuga
menziesii) seedlings grown at a site cleared of whiteleaf manzanita (Arctostaphylos viscida) and an
adjacent, cleared, annual grass meadow were either inoculated with 100-120 ml
per seedling of pasteurized or unpasteurized soil
from a nearby Pacific madrone (Arbutus menziesii) stand, or left uninoculated.
After one growing season, Douglas fir seedling whole-plant soil systems were
assayed for nitrogenase activity by the acetylene
reduction method. The rate of acetylene reduction in rhizospheres
of uninoculated seedlings from the manzanita site (1.40 +or- 0.44 nmol/h)
was significantly greater than that of uninoculated
seedlings from the meadow site (0.67 +or- 0.15 nmol/h).
Unpasteurized madrone soil
increased the rate of acetylene reduction by >500% for inoculated seedlings
grown on the manzanita site, but decreased it by 80%
for those grown on the meadow site. The influence of madrone
soil was apparently biotic: pasteurized madrone soil
did not have a significant effect. No acetylene was reduced in soil without
seedlings. Azospirillum sp., a microaerophilic nitrogen (N2) fixing bacterium, was
isolated from within the mycorrhizas of inoculated
seedlings harvested from the manzanita site. These
results suggest that early successional ectomycorrhizal shrubs and broadleaved trees may be
important in maintaining mycorrhizal fungi and
associated N2 fixers after severe disturbance.
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2. Bailey, V.L., J.L. Smith and H.
Bolton, Jr. 2002. Fungal-to-bacterial ratios in soils investigated for enhanced
C sequestration. Soil-Biology-and-Biochemistry 34(7): 997-1007.
Keywords: fertilization
soil properties
Abstract: Fungi
and bacteria govern most of the transformations and ensuing long-term storage
of organic C in soils. We assessed the relative contributions of these two
groups of organisms to the microbial biomass and activity of soils from five
different ecosystems with treatments hypothesized to enhance soil C
sequestration: (1) desert (an elevation gradient allowed comparison of soil
developed in a cooler, wetter climate with soil developed in a warmer, drier
climate), (2) restored tallgrass prairie (land
reverted to native prairie in 1979 and neighbouring
land farmed to row crops for ~100 year), (3,4) two forest types (Douglas fir [Pseudotsuga menziesii] and
loblolly pine [Pinus taeda],
unfertilized control and N-fertilized plots), and (5) agricultural land
(conventional- and no-till management systems). The selective inhibition
technique, using captan (fungicide) and oxytetracycline hydrochloride (bactericide), was used to
determine the activities (respiration) of fungi and bacteria in each of these
soils and substrate-induced respiration was used to measure total active soil
microbial biomass C. Phospholipid fatty acid analysis
was used to determine the composition of the soil microbial biomass and
determine if the activities and structure of the microbial communities were
related. Differences in fungal-to-bacterial (F:B)
activities between treatments at a site were greatest at the prairie sites. The
restored prairie had the highest F:B (13.5) and high
total C (49.9 g C kg-1 soil); neighbouring soil
farmed to maize had an F:B of 0.85 and total C of 36.0 g C kg-1 soil. Within
the pairs of study soils, those that were tilled had lower fungal activities
and stored C than those that were managed to native or no-till systems. In all
pairs of soils, soils that had higher absolute fungal activities also had more
total soil C and when two extreme cases were removed fungal activity was
correlated with total soil C (R2=0.85). Thus, in this small set of diverse
soils, increased fungal activities, more than F:B
ratios, were associated with increased soil C. Practices that involved invasive
land management decreased fungal activity and stored soil C compared to similar
soils that were less intrusively managed.
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3. Binkley, D. and P. Reid. 1985.
Long-term increase of nitrogen availability from fertilization of Douglas-fir.
Canadian-Journal-of-Forest-Research 15(4): 723-724.
Keywords: fertilization
growth
tree physiology
soil properties
Abstract: [See FA
44, 4708; 46, 1837] Most Douglas-fir stands respond to nitrogen fertilizing by
increasing stem growth for less than 8 yr, but one plantation at the United
States Forest Service Wind River Experimental Forest in Washington State has
responded for over 15 yr. In this study nitrogen concn. of foliage and fresh
litter were shown to be higher in the fertilized plots (470 kg/ha N) 18 yr
after fertilizing. Retranslocation of N from
senescent needles was not affected and stem growth per unit N in the canopy was
similar between unfertilized and fertilized plots. An index of soil N
availability in the fertilized plots was twice that of unfertilized plots. The
higher stem growth, leaf area, and stem growth per unit leaf area demonstrated
in an earlier study appeared to be related to a sustained increase in soil N
availability rather than increased N-use efficiency. An examination of soil N
transformation processes is needed to complete the explanation of the unusually
prolonged fertilizer response in these plots.
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4. Blake, J., S.R. Webster and S.P. Gessel. 1988a. Soil sulfate-sulfur and
growth responses of nitrogen-fertilized Douglas-fir to sulfur.
Soil-Science-Society-of-America-Journal 52(4): 1141-1147.
Keywords: fertilization
soil properties
growth
Abstract: Two
studies were conducted to determine the growth response of N-fertilized Douglas
fir [Pseudotsuga menziesii
(Mirb.) Franco] to S supplements. The relationship
between response and soil SO4-S extracted with Morgan's solution, 1.22 M NaOAc + 0.53 M HOAc (pH 4.8), was
used to establish critical levels for S. Douglas fir seedlings were grown in
the greenhouse in the surface mineral layer (0 to 0.15 m) of 20 forest soils
from western Washington and Oregon. On the average, significant increases in
total dry weight (17.5%), stem diameter (10.1%), and height (6.9%) occurred
when soils were fertilized with N and S in comparison to N alone. Using the Cate-Nelson procedure, growth responses to N and S were
most likely to occur when soil SO4-S was below 14 mg S kg-1. Twenty eight
installations were established in the field containing five treatments, three
rates of N as urea, and one plot of 336 kg N ha-1 with P, K, Ca, and S.
Differences in percent basal area growth between N alone and N with P, K, Ca,
and S were significantly related to soil SO4-S. Over the initial 5-yr period,
response over N alone was improved by 74% when soil SO4-S was <20 mg S kg-1.
When the N with P, K, Ca, and S plots were retreated with only N and S,
response over the next 3 yr was more than doubled compared with N alone.
Identification of S responsive stands was improved by the inclusion of stand
age weighted subsoil SO4-S concentrations.
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5. Brix, H. and A.K. Mitchell. 1986. Thinning and nitrogen
fertilization effects on soil and tree water stress in a Douglas-fir stand.
Canadian-Journal-of-Forest-Research 16(6): 1334-1338.
Keywords: thinning
fertilization
soil properties
tree physiology
Abstract: Soil
and tree water potentials were studied for 10 yr in a Douglas fir stand near Shawnigan Lake, British Columbia that was treated when 24
yr old with heavy thinning (removing superscript 2/3 of b.a.)
and/or fertilization with 448 kg N/ha as urea. Control plots were not thinned
or fertilized. Throughout the 10 yr, thinning increased soil water potential
during the dry summer periods (July-early Oct.) by as much as 1 MPa. The effect of fertilization on soil water potential
was slight and nonsignificant, and only apparent
towards the end of the study in spite of large increases in leaf area (50%
after 7 yr). Fertilization increased water use efficiency. The favourable soil water conditions produced by thinning led
to improved shoot water potential only during predawn and early morning.
Removal of understorey in a thinned and fertilized
plot did not affect soil or shoot water potential.
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6. Busse, M.D.,
G.O. Fiddler and A.W. Ratcliff. 2004. Ectomycorrhizal
formation in herbicide-treated soils of differing clay and organic matter
content. Water, Air, and Soil Pollution 152:23-34.
Keywords: release treatments
chemical release
growth
tree morphology
tree/stand health
soil properties
mycorrhizal response
Abstract: Herbicides
are commonly used on private timberlands in the western United States for site preparation and control of competing vegetation.
How non-target soil biota respond to herbicide applications, however, is not
thoroughly understood. We tested the effects of triclorpyr,
imazapyr, and sulfometuron
methyl on ectomycorrhizal formation in a greenhouse
study. Ponderosa pine, Douglas-fir, and white fir seedlings were grown in four
forest soils ranging in clay content from 9 to 33% and organic matter content
from 3 to 17%, and treated with commercial formulations of each herbicide at 0,
1.0, and 2.0 times the recommended field rate. Many of the possible
herbicide-soil combinations resulted in reduced seedling growth. Root
development was particularly sensitive to the three herbicides, with an average
of 51% fewer root tips compared to the control treatment. The ability of mycorrhizal fungi to infect the remaining root tips,
however, was uninhibited. Mycorrhizal formation was
high, averaging 91% of all root tips, regardless of herbicide, application
rate, soil type, or conifer species. In agreement, soil microbial biomass and
respiratory activity were unaffected by the herbicide treatments. The results
show that these herbicides do not alter the capability of mycorrhizal
fungi to infect roots, even at concentrations detrimental to seedling growth.
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7. Carr, W.W. 1987. Restoring productivity on degraded forest soils: two case studies.
B.C. Ministry of Forests FRDA-Report 002. vi + 21 p.
Keywords: site preparation
fertilization
tree physiology
growth
soil properties
Abstract: The use
of green fallowing was studied at 2 sites, viz. (a) a coastal site at Koksilah, 15 km NW of Shawnigan
Lake, British Columbia, where extensive subsoil exposure had resulted from roading operations in a highly productive Douglas fir (Pseudotsuga menziesii) and
western hemlock (Tsuga heterophylla)
stand, and (b) an inland site 30 km S. of Vanderhook including
several landings and skid roads which had been deep-ripped to a depth of 50 cm,
reducing soil density to 1350 kg/msuperscript 3.
Plots at (a) were seeded in 1976 at 100 kg/ha with a grass/legume mixture
including 3 spp. of Trifolium
and Lotus corniculatus, and received NPK (10:30:10) at 450 kg/ha. Site nutrient levels improved substantially
over 5 yr with N showing the greatest gains, and Douglas fir seedlings (1+2)
planted in 1977 responded with increased foliar N and K contents and 300%
greater ht. growth. Plots at (b) were seeded in 1981 at 40 kg/ha with a legume
mixture of 3 spp. of Trifolium,
Medicago sativa and L. corniculatus,
and received NPK (19:19:19) at 300 kg/ha. Nutrient gains were found after 2 yr for P,
K and especially N, and although foliar nutrient contents and growth of lodgepole pine (Pinus contorta) seedlings showed no increase, the enhancement of
site nutrient capital is considered to be a gain likely to benefit commercial
forestry production.
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8. Carter, R. and K. Klinka. 1992. Use of ecological site classification in the
prediction of forest productivity and response to fertilisation.
South-African-Forestry-Journal (160): 19-23.
Keywords: fertilization
growth
soil properties
Abstract: The
results are presented of two related studies in southern coastal British Columbia. A total of 149 study plots in even-aged immature Douglas
fir (Pseudotsuga menziesii)
stands were categorized into 6 ecologically similar site associations
(indicated best by climax plant communities) and into 15 soil moisture and soil
nutrient combinations, for the prediction of site index. Fifty-one of these
plots were used to predict basal area growth response to nitrogen fertilizer
(225 kg N/ha as urea). Regression models indicated strong correlations between
Douglas fir site index (m (height)/50 yr) and both indirect and direct measures
of soil moisture and nutrient regimes (Rsuperscript 2
>0.72; p <0.01). Third-year basal area response to N fertilizer varied
significantly among site associations (Rsuperscript 2
= 0.60; p <0.01). Site index also showed a significant relation with
third-year basal area response (Rsuperscript 2 =
0.52; p <0.01), while the best predictive model included site associations
and pretreatment foliar N and sulfate-S (Rsuperscript
2 = 0.64; p <0.01). It is suggested that the approach and methods of the
study are applicable to predicting site-specific growth performance and
response to fertilization of other tree species, including eucalypts.
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9. Carter, R.E., E.R.G. McWilliams
and K. Klinka. 1998. Predicting response of coastal
Douglas-fir to fertilizer treatments. Forest-Ecology-and-Management 107(1/3):
275-289.
Keywords: fertilization
growth
soil properties
Abstract: A
broadly-based, intensive Douglas-fir (Pseudotsuga menziesii) fertilizer experiment throughout southern
coastal British Columbia (48 sites) was used to examine 3- and 6-yr crop tree
growth responses to prescribed fertilizer applications (N alone, and N +
additional nutrients identified as potentially deficient by foliar analysis).
Absolute and relative basal area responses were evaluated in relation to site
associations of the provincial ecosystem classification system, site index
(SI), and a large number of site and stand chemical and physical properties.
Few of the site and stand variables examined as possible response prediction
criteria appeared to have any real utility. The strongest relationships found
were between relative basal area response and (1) site index (Rsuperscript 2 0.46 for both 3- and 6-yr responses), (2)
mineral soil mineralizable-N (Rsuperscript
2 0.50 and 0.46 for yr 3 and 6 responses, respectively), and (3) total mineralizable-N (Rsuperscript 2
0.47 and 0.50 for yr 3 and 6 responses, respectively). In all cases average
relative response declined with increasing site quality. However, there were
highly productive sites (SI50 <more or =>35 m) characterized by an
absence of growing-season water deficits and relatively low foliar N
concentrations (12-13 g/kg) which showed significant fertilizer responses.
These sites are where the greatest financial returns from fertilizing may be
realized. Relationships identified between site and stand variables and basal
area responses were, in many cases, different from those found by other
researchers for coastal Douglas fir. This brings the portability of identified
relationships into question.
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10. Chappell, H.N., D.W. Cole, S.P. Gessel and R.B. Walker. 1991. Forest fertilization research
and practice in the Pacific Northwest. Fertilizer-Research 27(1): 129-140.
Keywords: fertilization
soil properties
Abstract: A
review showed that most Pacific Northwest USA Douglas-fir (Pseudotsuga menziesii) forest sites are nitrogen deficient. Mineral
cycling research has shown high C:N ratios and low
nitrification rates for soils in the region. Research and development projects
in the Pacific
Northwest have
produced an information base that is used to select sites and stands for
fertilization and to forecast growth after treatment. Much of the basis for
operational fertilization programmes in western Oregon and Washington comes from cooperative research; current activities for
these programmes are directed toward improving
site-specific response information. Forest fertilization in the Pacific Northwest has become a major silvicultural
practice over the past two decades. Forest industry and government organizations managing forest
lands in western Oregon and Washington apply nitrogen fertilizer to Douglas-fir stands over a
range of soil and stand types. About 50 000 to 55 000 ha are fertilized each
year, and future programmes will probably be of
similar magnitude. Most current plans for management regimes including
fertilization require multiple applications.
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11. Chappell, H.N., C.E. Prescott and
L. Vesterdal. 1999. Long-term effects of nitrogen
fertilization on nitrogen availability in coastal Douglas-fir forest floors.
Soil-Science-Society-of-America-Journal 63(5): 1448-1454.
Keywords: fertilization
soil properties
Abstract: The aim
of this study was to determine if N availability was elevated 8 to 12 years
after repeated N fertilization, and if the effects of N fertilization were
related to the soil N capital. Rates of N cycling in control and fertilized
plots of Douglas-fir (Pseudotsuga menziesii)
in Oregon, USA, were compared by measuring net N mineralization rates in
forest floors and by estimating rates of N turnover from the litterfall/forest floor ratio. Litterfall
N contents, litter N concentrations, and rates of N turnover increased along
the gradient in soil N capital in both control and fertilized stands.
Fertilization did not affect litterfall N content,
but C:N ratios of litter and forest floors were
significantly lower in fertilized stands along the gradient. Turnover rates of
N in the forest floors were not higher in fertilized plots than in control
plots, nor were rates of net N mineralization affected by fertilization. Net
nitrification rates were higher in some of the plots that received 1120 kg N
ha-1 than in control plots. Nitrogen fertilization did not result in a
sustained increase in N cycling and N availability analogous to a higher site N
capital, and the effect of N fertilization was not related to the initial soil N
capital of these sites.
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12. Childs, S.W. and L.E. Flint. 1987.
Effect of shadecards, shelterwoods,
and clearcuts on temperature and moisture
environments. Forest-Ecology-and-Management 18(3): 205-217.
Keywords: planting operations
tree/stand health
soil properties
tree physiology
tree phenology
Abstract: A
comparison was made of two common techniques used to improve seedling survival
on hot, dry reforestation sites. Adjacent shelterwood
and clearcut sites in SW Oregon, USA, planted with 2+0 Douglas fir, were located and
instrumented to compare temp. and moisture. In
addition, cardboard shadecards were placed beside
half of the seedlings studied. Seasonal measurements or observations of soil
moisture, soil temp., solar radiation, air temp., stomatal
diffusion resistance, seedling phenology and survival
provided the basis for comparisons. Shelterwoods and shadecards improved seedling survival in relation to the clearcut. Both treatments affected soil temp. but the nature of the effects was different. The shelterwood canopy reduced solar radiation incident at the
soil surface and caused cooler soil temp. throughout
the soil profile. Shadecards reduced soil temp. only to a depth of 20 mm. Both treatments reduced the
duration of periods of high soil temp. Shelterwood
treatment delayed seasonal water loss and reduced seedling water stress as
measured by stomatal resistance. Shadecards
did not significantly affect seedling stomatal
resistance. Differences in seedling survival caused by shadecards
and shelterwoods are apparently due to different
influences on the seedling microclimate. Shelterwood
causes a large reduction in soil temp. as well as
decreased seedling water stress. Shadecards modify
the soil temp. less extensively and so have less
effect on seedling survival.
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13. Childs, S.W., H.R. Holbo and E.L. Miller. 1985. Shadecard
and shelterwood modification of the soil temperature
environment. Soil-Science-Society-of-America-Journal 49(4): 1018-1023.
Keywords: planting operations
soil properties
Abstract: A study
was conducted on steep, south-facing slopes in southwest Oregon to assess the effect of two common reforestation practices
on the soil thermal environment. Three clearcut sites
and three shelterwood sites were instrumented to
measure soil temperature at five depths in the vicinity of shaded and unshaded Douglas-fir seedlings. Since the soils studied
were skeletal, heat capacities of both fine and coarse soil fractions were
determined for each site. These data were used to estimate soil heat fluxes. Shelterwoods decrease soil temperatures approximately 6 K
when compared with clearcuts. This result holds at
both 20- and 320-mm depths. Shelterwoods also
decrease the depth of diurnal heating and decrease maximum hourly heat loss and
gain values by 73 and 80 W/msuperscript 2,
respectively. Shadecards, cardboard rectangles placed
to the southwest of seedlings, generally have little effect on the soil
temperature regime of skeletal soils but are effective in reducing daily heat
flux. The dominant shadecard effect is a decrease in
average daytime heat flux by 22 W/msuperscript 2, but
shadecards also decrease average nighttime fluxes. Shelterwoods ameliorate seasonal soil temperature
conditions significantly and may be an appropriate technique in situations
where cumulative soil heating limits reforestation success. Shadecards
should be useful in situations where heat stress events of only a few days are
a problem. Over a season, shadecards exert little
control, and their influence on stress is limited. Since all soils studied had
high heat capacities due to large rock fragment content the conclusions of this
study may be limited to soils with large soil heat capacity.
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14. Colinas, C., R. Molina, J. Trappe
and D. Perry. 1994a. Ectomycorrhizas
and rhizosphere microorganisms of seedlings of Pseudotsuga menziesii (Mirb.) Franco planted on a degraded site and
inoculated with forest soils pretreated with selective biocides. New-Phytologist 127(3): 529-537.
Keywords: planting operations
fertilization
soil properties
mycorrhizal response
Abstract:
Inoculation of planting holes with small amounts of soil from a mature forest
or a plantation can improve formation of ectomycorrhizas
on Pseudotsuga menziesii
seedlings in degraded clearcuts in southwestern Oregon. To determine the component(s) of transferred soil
responsible for increased ectomycorrhiza formation,
soil from a clearcut, a mature forest and a
plantation was treated with one of the following: (1) fertilizer to test for
the effect of nutrients, (2) dimethoate and carbofuran to test for the effect on microarthropods
or nematodes, (3) fumagillin to test for the effect
on protozoa, (4) captan to test for the effect on
fungi, (5) penicillin and oxytetracycline to test for
the effect on bacteria, (6) pasteurization to test for the effect of active
forms of organisms, (7) Tyndallization to test for
the effect of resting forms of organisms, or (8) water as a control. The effect
was studied of inoculation with soil subjected to these treatments on number
and types of ectomycorrhizas, on length of active
mycelium, and on number of active bacteria in the rhizosphere.
Inoculation with untreated forest or plantation soils increased the number of ectomycorrhizas but did not change the mycorrhizal
types present. Most agents had different effects in different soils.
Inoculation with pasteurized and Tyndallized
clearcut and plantation soils increased the number of
Rhizopogon- and Thelephora-type
ectomycorrhizas and decreased the number of active
bacteria, as did untreated forest soil. It is hypothesized that the role of the
soil transfer is to provide a rhizosphere environment
free from a deleterious organism present in the clearcut.
In this environment, beneficial organisms present in the clearcut
or brought in with the seedling from the nursery can proliferate.
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15. Curtis, R.O., D.D. Marshall and
D.S. DeBell. 2004. Silvicultural
options for young-growth Douglas-fir forests: the Capitol Forest study - establishment and first results. Pacific Northwest-Research-Station,-USDA-Forest-Service General-Technical-Report
PNW-GTR-598. xi
+ 110 p.
Keywords: thinning
commercial thinning
economics
soil properties
Abstract: This
report describes the origin, design, establishment and measurement procedures
and first results of a large long term cooperative study comparing a number of
widely different silvicultural regimes applied to
young-growth Douglas-fir (Pseudotsuga menziesii) stands managed for multiple objectives. Regimes
consist of (1) conventional clear felling followed by intermediate thinning;
(2) retention of reserve trees to create a two-aged stand; (3) small patch cuts
dispersed within a thinned matrix, repeated at approximately 15-year intervals
to create a mosaic of age classes; (4) group selection within a thinned matrix
on an approximate 15-year cycle; (5) continued thinning on an extended
rotation; and (6) an untreated control. Each of these regimes is on
operation-size units (approximately 30 to 70 acres each). A LIDAR system was
used to scan the surface of the 2 miles2 that encompass the Blue Ridge study site on the Capitol State Forest, near Olympia, Washington, USA. This measurement technology emits laser pulses that are
reflected by vegetation, buildings, or the ground surface. Output variables
from the study to be evaluated include conventional timber growth and yield
statistics, harvest costs, sale layout and administration costs, aesthetic
effects and public acceptance, soil disturbance, bird populations, and economic
aspects. Descriptive statistics and some initial results are presented for the
first replicate, established in 1997-98.
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16. Donegan,
K.K., L.S. Watrud, R.J. Seidler,
S.P. Maggard, T. Shiroyama,
L.A. Porteous and G. DiGiovanni.
2001. Soil and litter organisms in Pacific Northwest forests under different management practices. Applied Soil Ecology 18:159-175.
Keywords: planting operations
site preparation
prescribed fire
soil properties
Abstract: Soil
and litter organisms were monitored for their response to different forest
management practices. Litter and soil cores (0-10, 10-20 cm) were collected at
approximately 8-week intervals over a 19-month period from a low elevation
110-140-year-old Douglas fir (Pseudotsuga menziesii) forest and adjacent 8-year-old clearcut in the Oregon Cascades, and from a high elevation
200-250-year-old Douglas fir forest and adjacent 5-year-old clearcut
in the McKenzie River drainage. The low elevation clearcut
had been broadcast burned and replanted with Douglas fir trees and a grass (Dactylis and Lolium)-legume (Trifolium and Lotus) mixture whereas the high elevation clearcut was not burned, large woody debris was left, and
it was replanted with Douglas fir, Noble fir [Abies procera], Grand fir [Abies grandis], and western white pine [Pinus
monticola]. The litter and soil cores were analysed for types of microarthropods
and numbers of nematodes, fungi, culturable, aerobic
bacteria, spore-forming bacteria, and chitin-degrading bacteria. Microbial
community metabolic profiles, using the Biolog
method, were also generated for the 0-10 cm soil samples. Populations of
Pseudomonas spp. were analysed
in the litter and soil samples using 16S rDNA
fingerprints. Plant surveys were conducted to identify potential relationships
of soil organisms to plant community composition. At both elevational
field sites, there were significantly (P < 0.05) higher levels of nematodes
and microarthropods in litter and soil in forest
plots than in clear felled plots. Bacterial and fungal populations were also
significantly higher in litter in forest plots than in clear felled plots at
the high elevation site. In the litter and soil at the low elevation site and
the soil at the high elevation site, however, microbial levels were higher in
clear felled plots than in forest plots. The Pseudomonas spp.
populations and the microbial community metabolic profiles in the 0-10 cm soil
differed significantly between the forest and clear felled plots at the low
elevation site but not at the high elevation site. At both elevational
field sites, the plant cover (%) and plant density were significantly higher in
clear felled plots than in forest plots. These observed differences in the
population size and composition of organisms between mature forests and both
low management and high management clearcuts
demonstrated the impacts forest management practices may have on the soil
ecosystem.
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17. Edmonds, R.L. and T. Hsiang. 1987. Forest floor and soil influence on response of Douglas-fir to
urea. Soil-Science-Society-of-America-Journal 51(5): 1332-1337.
Keywords: fertilization
thinning
growth
soil properties
Abstract: Data
from the Regional Forest Nutrition Research Project (RFNRP) in Washington and Oregon were analyzed to improve stand-specific prediction of
Douglas-fir [Pseudotsuga menziesii
(Mirb.) Franco] response to urea
fertilization. The response variable (relative difference in volume
growth between fertilized and control plots 4 yr after fertilization with 448
kg N/ha) was regressed against 28 stand and site variables (e.g., age,
elevation, forest floor C/N ratio, soil cation
exchange capacity, etc.) using stepwise multiple regression analysis. Data from
120 installations were stratified by thinning level (thinned or unthinned), geographic location (provinces), and site
quality (site index and class). Forest floor C/N ratio was the dominant variable related to
response. In thinned installations of high site quality (site classes 1 and 2),
60% of variation in response was explained by the forest floor C/N, and 75% of
the variation in response was explained with inclusion of surface soil
exchangeable K. In thinned, low site quality stands, response was not as well
related to forest floor C/N. Analysis of the data by province indicated that S
may be limiting in southwest Oregon and P in coastal Washington.
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18. Feller, M.C. 1988. Relationships between fuel properties and slashburning-induced
nutrient losses. Forest-Science 34(4): 998-1015.
Keywords: site preparation
prescribed fire
soil properties
Abstract: The
relations between slash load, slash and forest floor consumption variables, and
species origin of slash (slash type) on one hand and nutrient (N, P, S, K, Na,
Mg and Ca) losses to the atmosphere during slashburning
on the other were studied by burning 50 plots, each 2.25 msuperscript
2 in area. The plots contained known amounts of slash materials derived from
four major southwestern British Columbia tree species (Tsuga heterophylla, Thuja plicata, Chamaecyparis nootkatensis and Pseudotsuga menziesii) and were burned under different weather
conditions. Nutrient losses (g/msuperscript 2)
decreased in the order N > Ca > S > K > Mg > P > Na and were
generally within the range of such losses recorded for operational prescribed
burns in western North America. Losses of all nutrients except Na were positively
correlated with fuel consumption. Nitrogen and S exhibited the best
correlations, whereas no correlations were found for Na. Of the fuel
consumption variables considered, depth of forest floor consumed, then total
slash consumption, were best correlated with nutrient loss. Losses of most
nutrients generally increased with slash load and as slash type changed from Tsuga to Pseudotsuga to Thuja/Chamaecyparis. This was partly due to the effects of
slash load and slash type on fuel consumption, and partly due to their effects
on burning-caused changes in nutrient concn. in slash materials. The study suggests that nutrient losses
to the atmosphere during operational slashburns can
be minimized by minimizing forest floor and large diameter slash consumption
during burning.
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19. Feller, M.C. 1990. Herbicide
application followed by prescribed fire to convert a brushfield
into a conifer plantation in south coastal B.C.: a combination of the initial
effects of two treatments. B.C. Ministry of Forests FRDA
Report 146. 40 p.
Keywords: site preparation
chemical preparation
prescribed fire
growth
tree/stand health
soil properties
stand conditions
Abstract: A field
study was carried out in Pseudotsuga menziesii stands in British Columbia, Canada, to investigate the effects on vegetation of glyphosate applications in September 1987 or July 1988,
followed by burning in October 1988. Results did only show slight differences
between treatments.
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20. Feller, M.C., J.P. Kimmins and K.A. Scoullar. 1983.
FORCYTE-10: calibration data and simulation of potential long-term effects of
intensive forest management on site productivity, economic performance, and
energy benefit/cost ratio. In I.U.F.R.B. Symposium
on. Forest Site and Continuous Productivity; Seattle, Washington; August 22-28, 1982. Eds. R. Ballard and S.P. Gessel. Pacific-Northwest-Forest-and-Range-Experiment-Station,
USDA-Forest-Service General-Technical-Report PNW-GTR-163 Part B. 179-200 pp.
Keywords: thinning
fertilization
soil properties
economics
computer modeling
Abstract: FORCYTE
(FORest nutrient Cycling and Yield Trend Evaluator) is a computer
simulation model of forest plant biomass production, litterfall,
and decomposition, complete with nutrient cycling, nutrient limitation on
growth, and a variety of management interventions. The model is a computerized
approach to the estimation of the effects of varying thinning and fertilizer
regimes, utilization level, and rotation length on site nutrient budgets, stand
productivity, and the economic performance and energy efficiency of management.
The model has evolved over 5 years to its present version FORCYTE-10, which is
briefly described. Accompanying the development of FORCYTE, there has been a
series of field research projects. Detailed biomass and biogeochemical
descriptions of age sequences of Douglas-fir stands on both good and poor sites
have been prepared for purposes of model calibration and testing. The present
report summarizes some of the results of the FORCYTE-10 field studies on Vancouver Island, British Columbia, and presents some examples of the use of the model when
calibrated with these data.
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21. Flint, L.E. and S.W. Childs. 1987. Effect of shading, mulching,
and vegetation control on Douglas-fir seedling growth and soil water supply.
Forest-Ecology-and-Management 18(3): 189-203.
Keywords: release treatments
chemical release
manual release
growth
soil properties
Abstract: Harsh
environments on many harvested sites in SW Oregon necessitate site modifications for successful regeneration
of Douglas fir. A 2-yr study was made with 350 seedlings to assess the effects
of 12 soil-surface shading, mulching, and vegetation control techniques on
seedling growth and soil temp. and moisture
environments. Major effects of treatments were to lower soil surface temp.,
reduce soil surface evaporation, and reduce vegetative competition for soil
water. These affected seedlings by adjusting the timing of seedling growth and
reducing soil water loss to increase available water for seedling use. Final
seedling shoot vol. and stem diam. both differed
among treatments. Seedlings in treatments where competing vegetation was
controlled showed significantly greater growth than seedlings in other
treatments. Soil water loss in treatments where either soil surface evaporation
was controlled by mulching, or where competing
vegetation was controlled, was significantly less than water loss from the
shaded and control treatments. Soil water loss in treatments with vegetation
controlled by herbicide was significantly less than in treatments with
vegetation controlled by scalping. Seedlings showed greatest growth with
treatments that elicited the most efficient use of available microsite water either by reducing soil surface evaporation
or vegetation competition.
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22. Fox, T.R. 2004. Nitrogen
mineralization following fertilization of Douglas-fir forests with urea in Western Washington. Soil-Science-Society-of-America-Journal 68(5): 1720-1728.
Keywords: fertilization
soil properties
Abstract:
Nitrogen mineralization following repeated applications of urea fertilizer was
determined in the A horizon soil from two stands of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in the Cascade Mountains of Washington.
Repeated applications of urea at rates ranging from 0 to 600 kg N ha-1 were
made at annual and 5-yr intervals over a 6-yr period. Nitrogen fertilization
increased N mineralization potential in these soils. However, soil N
mineralization followed a quadratic relationship with the total amount of N
applied in fertilizer over the 6-yr treatment period, increasing up to total
application rates of 450 kg N ha-1 and then declining at higher rates. The
decrease in N mineralization rates at the high N fertilization rates may be due
to changes in the quality of soil organic matter, which reduced the
effectiveness of extracellular enzymes and decreases
the rate of decomposition and mineralization. Soil pH dropped following urea
fertilization, with greater declines observed in the highest rates of urea
fertilizer. Decreases in extractable Ca and Mg levels in the soil accompanied
the decline in soil pH. These results suggest that high rates of nitrification
occurred and that nitrate leaching was stripping Ca and Mg from the cation-exchange complex in these soils. It appears that
repeated applications of urea fertilizer at low to intermediate rates may
increase long-term N availability and thus improve soil quality. However,
annual applications of high rates of urea may decrease soil quality because
under these circumstances N mineralization did not increase and there was a
loss of cations from the soil.
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23. Frey Klett,
P., J.L. Churin, J.C. Pierrat
and J. Garbaye. 1999. Dose effect in the dual inoculation of an ectomycorrhizal fungus and a mycorrhiza
helper bacterium in two forest nurseries. Soil Biology and Biochemistry
31:1555-1562.
Keywords: nursery operations
growth
carbon allocation
mycorrhizal response
soil properties
Abstract: Disinfected
soil at two Douglas-fir (Pseudotsuga menziesii) bare-root forest nurseries was inoculated with
three doses (8 X105, 8 X107 and 8 X109 cfu [colony
forming units]/m2) of the rifampicin-resistant mycorrhiza helper bacterium Pseudomonas fluorescens
strain BBc6R8 and the ectomycorrhizal fungus Laccaria bicolor strain S238N. In one of the two nurseries,
two doses of fungal inoculum (50 and 100 mg/m2 dry
weight (DW) mycelium entrapped in alginate beads at the constant dose of 1
litre/m2) were tested. For all bacterial treatments the density of P. fluorescens BBc6R8 in the soil, determined by dilution
plating, dropped below the detection limit (10-2 cfu/g
DW soil) 2 weeks after inoculation. Fifteen weeks after inoculation, the
introduced bacterium was detected by enrichment only in the treatments
inoculated with the highest bacterial dose. Two years after inoculation, P. fluorescens BBc6R8 was not detected in the soil of any of
the bacterial treatments. Five months after inoculation and sowing, bacterial
inoculation significantly increased the percentage of mycorrhizal
short roots on plants inoculated with either low or high amounts of L. bicolor,
in one of the nurseries. The lowest bacterial dose increased mycorrhizal colonization from 45 to 70% in plants
inoculated with the low amount of fungal inoculum,
and from 64 to 77% in plants inoculated with the high amount of fungal inoculum. The lowest bacterial dose increased mycorrhizal colonization more than the highest bacterial
dose. The same L. bicolor mycorrhizal index (70%) was
obtained with 50 mg/m2 DW mycelium plus the bacterium than with twice this
fungal dose and no bacterium (64%). Two years after inoculation, the height of
the mycorrhizal Douglas-firs in the other nursery was
significantly increased by the lowest bacterial dose (from 40.7 to 42.6 cm). It
was indicated that co-inoculating a helper bacterium together with an ectomycorrhizal fungus is an efficient way to optimize
controlled mycorrhization techniques for the
production of high-quality Douglas-fir planting stocks. It was confirmed that
BBc6R8 acts at a low population density (less than 10-2 cfu/g
soil), this contrasts with most PGPR [plant growth
promoting rhizobacteria?] effects where the minimal
inoculation dose of 105 cfu/g soil is required to
obtain the beneficial effect.
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24. Gagnon, J., C.G. Langlois, D. Bouchard, F.l. Tacon and F. Le Tacon. 1995.
Growth and ectomycorrhizal formation of
container-grown Douglas-fir seedlings inoculated with Laccaria
bicolor under four levels of nitrogen fertilization.
Canadian Journal of Forest Research 25:1953-1961.
Keywords: nursery operations
nursery fertilization
growth
carbon allocation
tree physiology
tree morphology
mycorrhizal response
soil properties
Abstract:
Container-grown Douglas fir (Pseudotsuga menziesii) seedlings were inoculated at the time of sowing
with a Laccaria bicolor mycelial
suspension produced in a fermentor. They were grown
in a peat moss-vermiculite substrate under four levels of N fertilization (7.2,
14.4, 21.6 and 28.7 mg/seedling per season (N1, N2, N3 and N4, respectively))
to determine the N level suitable for both ectomycorrhizal
development and seedling growth. After 18 weeks in the greenhouse, seedlings
inoculated with L. bicolor had 44%, 32%, 44% and 5% of their short roots mycorrhizal when fertilized with N1, N2, N3 and N4,
respectively. Only when they were fertilized with N4 did the L. bicolor
seedlings have significantly greater shoot height than the controls. For the
other growth parameters, they were not significantly different from control seedlings
for any of the N levels. After 18 weeks, regardless of the level of N,
seedlings inoculated with L. bicolor had significantly lower N concentrations
(%) and contents (mg/seedling) than the uninoculated
ones. Consequently, for the same production of biomass, the mycorrhizal
seedlings had taken up less N than the nonmycorrhizal
ones. The efficiency of applied N, expressed in terms of produced biomass,
decreased when the N fertilization increased; mycorrhizal
and nonmycorrhizal seedlings did not tend to be
different. The efficiency of the absorbed N also decrease
with the level of applied N, but less rapidly, and tended to be greater for the
mycorrhizal seedlings than for the nonmycorrhizal ones. Therefore, the mycorrhizal
infection improved the utilization of the absorbed N. N3 was the best of the four N levels used, since it was the
only one that maximized both the ectomycorrhizal
formation and the growth of the seedlings. In other words, a total seedling N
concentration of 1.6% and a substrate fertility of 52 p.p.m.
N are appropriate to optimize both the ectomycorrhizal
development and the growth of Douglas fir seedlings.
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25. Gessel,
S.P., R.E. Miller and D.W. Cole. 1990. Relative importance of water and nutrients
on the growth of coast Douglas fir in the Pacific Northwest. Forest-Ecology-and-Management 30(1-4): 327-340.
Keywords: fertilization
growth
soil properties
Abstract: The
Douglas-fir region in northwestern North America is characterized by abundant moisture supply during
winter, extended dry periods during the growing season and significant
differences in water availability. Many soils have low fertility and indigenous
tree species respond to nitrogen fertilization, especially Douglas fir (Pseudotsuga menziesii). Although
irrigation of commercial forests in this region is currently impractical,
questions arising about the relative importance of water and nutrients were
examined using long-term growth data from three studies. At Pack Forest (Washington), fertilization without irrigation doubled growth rates,
and no positive growth responses were measured from irrigation. Short-term (5
yr) irrigation with sewage effluent containing many nutrients resulted in a
six-fold increase in biomass production for poplar and three-fold for Douglas
fir as compared to irrigation with equal volumes of river water. Volume growth
in 12- to 65-yr-old stands in southwestern Oregon was increased by fertilization at about 70% of the
locations; annual gain averaged 2.73 msuperscript
3/ha for 5-12 yr. Response was not related to annual precipitation, which
ranged from 81 to 279 cm, nor other moisture-related variables. Absolute and
relative volume response showed highest correlation with soil carbon : nitrogen ratio. Compared with nutrition, moisture
does not seem to be a major limiting factor for growth in the Douglas fir
region of the Pacific
Northwest.
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26. Harrison, R., D.S. Xue, C. Henry and D.W. Cole. 1994a.
Long-term effects of heavy applications of biosolids
on organic matter and nutrient content of a coarse-textured forest soil.
Forest-Ecology-and-Management 66(1/3): 165-177.
Keywords: fertilization
soil properties
Abstract:
Long-term changes in soil properties due to a single heavy application of
municipal biosolids (municipal sewage sludge) on a
coarse-textured glacial outwash soil were evaluated. Study sites, located at
the Pack Experimental Forest, 100 km S. of Seattle, Washington, were clearcut, cleared, fertilized with 500 t/ha of municipal biosolids and planted with either Lombardy poplar (Populus nigra var. italica), Douglas fir (Pseudotsuga
menziesii) or ponderosa pine (Pinus
ponderosa) in 1975. Soil samples were taken in 1990 from treated stands and
from adjacent (unamended) control sites by horizon to
a depth of 185 cm. Biosolids-amended samples had
greater amounts (mg/g) of C (139 vs. 67), N (12 vs
3.4), P (14 vs. 2.2) and S (2.5 vs. 0.4) contents in 0-7 cm mineral soil and
other surface soil horizons, compared with control soil horizons, but showed no
significant differences below 25 cm. Soil pH ranged from 0.4 to 1.0 units lower
in biosolids-amended vs. unamended
soil throughout the sampled soil horizon. Soil cation
exchange capacity was higher in the surface soil horizons of treated plots (30
vs. 18 mmolc kg-1 in 0-7 cm soil), but there were no
significant differences below 50 cm. Biosolids-amended
samples had greater amounts (mg/g) of total Ca (13 vs. 6.1 in 0-7 cm soil) and
K (1.9 vs. 1.5 in 0-7 cm soil) throughout the sampled soil profile. Total Mg
was relatively constant (2.0-3.0) throughout the sampled soil profile. Study
results indicate that one of the primary objectives of the original biosolids application (increasing total nutrients in the
rooting zone of the forest soil) extended at least 15 years from the
application date.
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27. Harrison, R.B., S.P. Gessel, D. Zabowski, C.L. Henry,
D.S. Xue, D.W. Cole and J.E. Compton. 1996.
Mechanisms of negative impacts of three forest treatments on nutrient
availability. Soil-Science-Society-of-America-Journal 60(6): 1622-1628.
Keywords: fertilization
growth
soil properties
tree/stand health
Abstract: Many
forest management treatments are directly aimed at maintaining or enhancing
forest productivity. There may also be secondary effects that detract from this
goal. Three case studies in Washington state, USA, are discussed in which several mechanisms may have led to
adverse secondary impacts. In the first study, pulp and paper (PIT) sludges were mixed into soil and growth of Douglas-fir (Pseudotsuga menziesii), noble fir
(Abies procera) and western
white pine (Pinus monticola)
was monitored. There was a significant negative correlation of height and
diameter growth and C:N ratio for Douglas-fir and
western white pine. In a second study, effects of 50 years of red alder (Alnus rubra) and Douglas-fir
growth on soil chemistry and stand productivity were compared. When the
50-year-old stands were cut and red alder was established by planting into the
soil of the former Douglas-fir and red alder forests, a reduction in available
P in the soil of the previous red alder stand was observed. In a third study,
high rates of low C:N ratio organic matter (300 t/ha)
were added in municipal biosolids (~8000 kg N/ha) to
Douglas-fir and grand fir (Abies grandis)
plantations. Excess organic N in the biosolids
apparently mineralized, nitrified, and contributed to soil acidification and
accelerated cation leaching. Severe Mg deficiency
(0.25 g/kg in biosolids-treated vs. 0.93 g/kg in
untreated areas) might be the cause of observed foliar chlorosis
and poor growth rates.
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28. Harrison, R.B., C.L. Henry, D.W. Cole and D. Xue.
1995. Long-term changes in organic matter in soils receiving applications of
municipal biosolids. In Carbon forms and
functions in forest soils. Eds. W.W. McFee and J.M. Kelly. Soil Science
Society of America Inc., Madison WI. pp. 139-153.
Keywords: fertilization
soil properties
Abstract: Soil concn of C, N, P, Ca, Mg, K, pH, and CEC were compared at
two forest sites of contrasting mineralogy and management in Washington, U.S.A., after the application of municipal biosolids.
The soil on the Pack forest site was an extremely coarse-textured outwash soil
whilst that of the Mt. Pilchuck Tree Farm was a sandy
outwash soil. The Pack forest was characterized by 80-yr-old second growth Douglas
fir (Pseudotsuga menziesii)
with an understory of salal
(Gaultheria shallon). The Mt. Pilchuck
Tree Farm site was characterized by 60-yr-old second growth Douglas fir with an
understory of salal. Both
sites were harvested and cleared prior to the initiation of the studies. The
forest floors were different in the biosolids-amended
soils compared with the unamended soils, with more
highly humified material and fewer fine roots. Large
increases in C, N, and P concn in the amended plots
were restricted to the top 27 cm of soil. Ca and Mg increases were observed at
the Pack Forest amended site but not at the Mt. Pilchuck
Tree Farm site. At both sites the pH was lower in the amended plots. The
differences between the sites are discussed with reference to soil type and
management practices. Implications for long-term nutrient retention are
considered.
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29. Harrison, R.B., C.L. Henry and D.S. Xue.
1994b. Magnesium deficiency in Douglas-fir and grand fir growing on a sandy
outwash soil amended with sewage sludge. Water, Air, and Soil Pollution
75(1/2): 37-50.
Keywords: fertilization
tree/stand health
tree physiology
soil properties
Abstract: Soil and
plant samples were collected from chlorotic
plantations of grand fir (Abies grandis)
and Douglas fir (Pseudotsuga menziesii)
near Seattle, Washington state, USA, in winter 1989. The soils had been amended in 1981 with
an average of 300 dry t/ha of municipal sewage sludge. The sludge amendment
resulted in an N application rate of approximately 8000 kg/ha. Foliage analysis
indicated that a severe Mg deficiency (0.25 g/kg in sludge-treated vs. 0.93
g/kg in untreated areas) might be the cause of chlorosis.
No other nutrient showed concentrations in the deficient or toxic ranges. Trace
metal levels in foliage were increased significantly for Ni, Cd and Cr at sludge-treated sites, but were not at toxic
levels. Soil samples taken to a depth of 1.4 m indicated the potential for soil
acidification (up to 0.9 pH unit) in soil surface horizons. In addition,
exchangeable Ca, Mg and K may have been depleted in surface horizons.
Exchangeable Al and Fe were greater in the surface of sludge-treated sites.
These observations, and the loss of much of the nitrogen added during the
sludge amendment, indicated that nitrification and cation
leaching were the most likely mechanism for acidification and depletion of
exchangeable cations. Fertilizing the plantation with
MgSO4 or dolomitic limestone was carried out in
spring 1990. New foliage collected in June 1990 was non-chlorotic
and significantly higher in Mg concentration than unfertilized foliage (1.1.
vs. 0.7 g/kg, respectively). The results of this study indicate that it is important
to assess the potential for initiating a nutrient deficiency due to secondary
effects of sludge application in forest systems.
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30. Heilman,
P. 1983. Effects of surface treatment and interplanting
of shrub alder on rowth of Douglas-fir on coal
spoils. Journal-of-Environmental-Quality 12(1): 109-113.
Keywords: planting operations
site preparation
mechanical preparation
growth
tree physiology
soil properties
tree/stand
health
Abstract: Annual
growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) planted
on topsoiled spoils at a coal mine near Centralia, Wash., was monitored for the first 6 y after planting.
Treatments were contour bedding, contour bedding plus interplanted
Sitka alder (Alnus sinuata
(Reg.) Rydb.), and unbedded
control. The bedding significantly increased growth of Douglas-fir in all 5 y
of the study. Total height growth after 5 y was 35% greater than control on the
bedding only plots, and 43% greater on the bedding plus Sitka alder plots. Height growth of Douglas-fir in the mixed
stand was significantly greater during the 2nd and 3rd y of the study, but
after 5 yr, no significant difference was evident in total height between the
mixed and pure Douglas-fir plots. Concentration of N in Douglas-fir foliage was
significantly increased by bedding in the fifth but not in the fourth year. Interplanting with Sitka alder had no significant effect on N in Douglas-fir
foliage. The top 0.3 m of soil in the ridged portion of the bedded area
contained significantly less moisture over a summer than did the top 0.3 m of
the unbedded soil. At deeper depths, however, soil
moisture was not significantly affected by bedding. Wind damage caused by a
severe storm that occurred after 5 y was very much greater on the unbedded plots (49% wind-thrown vs. 9 to 15% wind-thrown on
the bedded plots) despite the smaller size of the trees on unbedded
plots.
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31. Henry, C.L. 1987. Growth
response, mortality, and foliar nitrogen concentrations of four tree species
treated with pulp and paper and municipal sludges. In
The-forest-alternative-for-treatment-and-utilization-of-municipal-and-industrial-wastes.
Eds. Cole, D.W., C.L. Henry, and W.L. Nutter.
University of Washington Press, Seattle, Washington, USA.
pp. 258-265.
Keywords: nursery operations
nursery fertilization
soil properties
growth
tree/stand health
tree physiology
Abstract: Four
nursery beds at the University of Washington Charles
Lathrop Pack Demonstration Forest were each divided into plots that received 8
sludge treatments before being planted with seedlings of Douglas fir, Abies procera or Pinus monticola, or cuttings of Populus deltoides X P. trichocarpa. Each sludge and the unamended
soil were analysed for total solids, total C, P and
K, total N and NH4-N. Ht. and diam. were measured
after planting in April 1984 and again in Feb. 1985. N was determined in
foliage sampled during Oct. (Populus) or Feb. (other
species). Addition of pulp and paper sludge alone and combined with municipal
sludge provided predictable growth responses when compared with the C : N ratio of each treatment. Av. response was positive
when the C : N ratio was more favourable
than that of untreated soil, but av. response was negative when soil was
treated with primary pulp and paper sludge with a very high C : N ratio.
Treatments that produced the greatest growth also increased seedling mortality.
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32. Henry, C.L., D.W. Cole and R.B.
Harrison. 1994. Use of municipal sludge to restore and improve site
productivity in forestry: The Pack Forest Sludge Research Program.
Forest-Ecology-and-Management 66(1/3): 137-149.
Keywords: fertilization
growth
soil properties
stand conditions
Abstract:
Municipal wastewater residuals - sludge or biosolids
- represent a major waste by-product from society that must be managed in
responsible ways. Because of its high nutrient and organic matter content,
sludge can be beneficially recycled into forest sites for site improvement
purposes. This paper reviews the opportunities and problems that have been
encountered during 20 yr of research into sludge application in forests, based
on data from studies carried out in the Pack Demonstration Forest, Washington,
on a variety of sites - including clear-felled, young or mature Douglas fir [Pseudotsuga menziesii] stands,
and rights-of-way. Research to date on forest application of sludge has been
very encouraging, clearly demonstrating the validity of this management
technique. Forest sites typically display benefits in two ways: (1) an
immediate growth response by both overstorey and understorey species; (2) a long-term improvement to the
productivity of the site. However, for this practice to have broad utility and
acceptance, it is critical that the concerns of the regulatory agencies and
general public be addressed regarding public health and environmental issues
through continued research. These concerns include the fate of trace metals,
including movement, uptake and potential phytotoxicity,
and passage into wildlife and human food chains, the fate of pathogens, and
leaching of nitrates into groundwater systems. Many concerns are a result of
misconceptions or misunderstandings of the potential problems involved and
require working with these agencies and the general public through education
and demonstration programmes.
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33. Henry, C.L., D.W. Cole, T.M.
Hinckley and R.B. Harrison. 1993. The use of municipal and pulp and paper sludges to increase production in forestry.
Journal-of-Sustainable-Forestry 1(3): 41-55.
Keywords: nursery operations
nursery fertilization
fertilization
thinning
growth
tree/stand health
soil properties
Abstract: Because
of their high nutritional content and soil conditioning properties, municipal
and pulp and paper (P&P) sludges (biosolids) can serve as soil amendments for nutritionally
deprived or organically poor soils on forest sites. Studies conducted over the
past 20 years at an experimental forest site in Western Washington, USA, have largely confirmed the potential of biosolids to increase the productivity of many forest
lands. These studies clearly demonstrated that application of biosolids at environmentally acceptable rates will result
in growth responses for both young seedlings as well as established stands.
Municipal biosolids have been applied to a number of
Douglas fir (Pseudotsuga menziesii)
stands. Young stands treated with 47 t/ha showed an average of 72, 14 and 2%
height responses for Site Class IV, III and II, respectively, over a 10 year
period. Thinned versus unthinned 55-year-old Douglas
fir treated with 142 dry t/ha averaged 43 and 48%, respectively, for the 12
year period greater than controls. Average growth responses of 65 and 40%
occurred in the 65-year-old stand for the Site Class IV and II, respectively,
from a 47 dry t/ha application. Growth response resulting from application of
P&P biosolids to a number of tree species
(Douglas fir, Pinus monticola
and Abies procera in
nursery beds, and plots of Populus deltoides x P. trichocarpa rooted
cuttings) has also been excellent. When properly applied, biosolids
can provide an excellent alternative to chemical fertilizers as a means of
enhancing forest production. Growth response is typically greater and lasts
longer when compared with chemical fertilizers.
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34. Hetherington, E.D. 1985. Streamflow
nitrogen loss following forest fertilization in a southern Vancouver Island watershed. Canadian-Journal-of-Forest-Research 15(1): 34-41.
Keywords: fertilization
soil properties
Abstract: Water
quality was monitored in the Lens Creek catchment to
determine nitrogen loss following aerial application of 224 kg/ha N (as urea)
to a second-growth Douglas-fir forest in Sept. 1974. Peak nitrogen
concentrations measured in 2 small tributary streams were 14 mg/litre as urea (after 12 h), 1.9 mg/litre
as ammonia (after 24 h), and 9.3 mg/litre as nitrate
(after 7 wk). For the first 14 months, estimated nitrogen outputs in excess of
background amounts were 5.9 and 14.5% respectively of the total nitrogen
applied to the 2 subsidiary catchments which had 46 and 80% of their drainage
areas fertilized. These losses were considerably higher than amounts of <1%
previously reported for western North America. Increased amounts of urea N and ammonia N were
short-lived, while nitrate N remained above background values for the duration
of the study. Reasons for the high nitrogen loss include nitrification of the
urea during 7 wk of mild, dry weather following fertilizing, the presence of
alder and swampy areas adjacent to the streams, high soil permeability, steep
slopes, and abundant, above average early winter rainfall. The catchments had
been fertilized previously in 1967-68 and 1972 but any influence of this on
nitrogen loss during the present study is unknown. Lens Creek water quality was
not adversely affected by the fertilizing in terms of drinking water standards
or toxicity to fish.
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35. Homann,
P.S., B.A. Caldwell, H.N. Chappell, P. Sollins and
C.W. Swanston. 2001. Douglas-fir soil C and N
properties a decade after termination of urea fertilization.
Canadian-Journal-of-Forest-Research 31(12): 2225-2236.
Keywords: fertilization
soil properties
Abstract: Chemical
and microbial soil properties were assessed in paired unfertilized and urea
fertilized (>89 g N/m-2) plots in 13 second-growth Douglas fir (Pseudotsuga menziesii) stands
distributed throughout western Washington and Oregon, USA. A decade following
the termination of fertilizer application, fertilized plots averaged 28% higher
total N in the O layer than unfertilized plots, 24% higher total N in surface
(0-5 cm) mineral soil, and up to four times the amount of extractable ammonium
and nitrate. Decreased pH (0.2 pH units) caused by fertilizer application may
have been due to nitrification or enhanced cation
uptake. In some soil layers, fertilizer application decreased cellulase activity and soil respiration but increased wood
decomposition. There was no effect of fertilizer application on concentrations
of light and heavy fractions, labile carbohydrates, and phosphatase
[phosphoric monoester hydrolases] and xylanase activities. No increase in soil organic C was
detected, although variability precluded observing an increase of less than
~15%. Lack of a regionwide
fertilizer application influence on soil organic C contrasts with several
site-specific forest and agricultural studies that have shown C increases
resulting from fertilizer application. Overall, the results indicate a
substantial residual influence on soil N a decade after urea fertilizer
application but much more limited influence on soil C processes and pools.
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36. Hopmans,
P. and H.N. Chappell. 1994. Growth response of young, thinned Douglas-fir
stands to nitrogen fertilizer in relation to soil properties and tree
nutrition. Canadian-Journal-of-Forest-Research 24(8): 1684-1688.
Keywords: fertilization
growth
soil properties
tree physiology
Abstract: Application
of 224 kg N/ha to young, thinned stands of Douglas fir (Pseudotsuga
menziesii) at 35 sites in W. Oregon and Washington
significantly increased basal area and volume increment over 8 years following
treatment. However, response varied considerably between sites, and relative
volume increment exceeded 10% at only 19 of the 35 sites. Response to applied N
was evaluated in relation to forest floor and soil variables as well as to
levels of N in foliage. Relative responses in basal area and volume were
significantly correlated with total N concentration and the C/N ratio of the
soil. However, these relationships explained only part (18-22%) of the observed
variation in response. In contrast, relative response was strongly correlated
with the level of N in the foliage of non-fertilized trees at 11 sites,
accounting for 94% of the variation between sites. It is suggested that foliar
N could be used to predict growth responses to N fertilizers in young thinned
Douglas fir stands.
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37. Murray, M.D. and R.E. Miller.
1986. Early survival and growth of planted Douglas-fir with red alder in four
mixed regimes. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-366. ii + 13 p.
Keywords: planting operations
release
treatments
growth
stand
conditions
Abstract: To
quantify interactions between species, the survival and growth of planted
Douglas fir in association with volunteer or planted red alder (Alnus rubra) were studied at a
site on the W. side of the Cascade Range, Washington. The planted alders were
wildings taken either from a nearby site or from a distant coastal site and interplanted in a 3-yr-old Douglas fir plantation. The
volunteer alders established during the first year and were cut when the
plantation was 3 or 7 yr old. There was no apparent advantage in using
non-local alder to reduce aboveground competition with Douglas fir. Survival of
both sources of transplanted alder was high. Retaining about 1100 plants/ha of
volunteer alders until plantation age 7 yr had no measurable effect on Douglas
fir. It is recommended that, with alder densities of <1250/ha, alder control
on most land of average or below average site quality can be delayed until 6-8
yr after planting Douglas fir. This will reduce alder sprouting and allow
simultaneous control of alder and precommercial
thinning of Douglas fir.
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38. Jacobs, D.F., R. Rose, D.L. Haase and P.D. Morgan. 2003b. Influence of nursery soil
amendments on water relations, root architectural development, and field
performance of Douglas-fir transplants. New-Forests 26(3): 263-277.
Keywords: nursery operations
fertilization
tree physiology
tree morphology
growth
carbon allocation
soil properties
tree/stand health
Abstract: This
experiment evaluated the influence of manure, peat, and vermiculite
incorporated at low and high rates (0.0118 and 0.0236 m3/m2) and under two soil
moisture regimes on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
seedling (1+0 for 1+1) xylem water potential ( Phi
xylem), whole-plant growth, root architectural development, and subsequent
field performance under fertilized and non-fertilized conditions. Trends in
soil moisture retention were observed (high manure > high peat > control)
but there were no differences in Phi xylem. Root length in the wetter soil
moisture experiment was initially (three months) greatest for seedlings in high
vermiculite and least in high manure but there were no differences among
treatments at lifting (eight months). Mean height was greatest for seedlings
grown in vermiculite and peat (wetter nursery experiment) after two field
seasons. Field fertilization (35 g/seedling) with controlled-release fertilizer
in the planting hole stimulated height growth
initially, but decreased height and diameter growth during the second growing
season. Dramatic improvements associated with the use of nursery soil
amendments were not realized, but the failure to identify negative effects, a
potential reduction in disease incidence, and improvement of nursery soil
physical and chemical properties may justify their use.
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39. Kabzems, R.D. and K. Klinka. 1987.
Initial quantitative characterization of soil nutrient regimes. I. Soil
properties. Canadian-Journal-of-Forest-Research 17(12): 1557-1564.
Keywords: fertilization
soil properties
Abstract: Data on
properties of the forest floor and mineral soil were collected from 6 Douglas
fir ecosystems on southern Vancouver Island. Data were analysed to determine
whether soil properties reflecting nutrient status differed significantly from
soil nutrient regimes assessed using selected vegetation, environmental and
physiographic features. The sum of mineralizable N,
total N and exchangeable Ca and Mg in mineral soil and forest floor were the
properties that best characterized the soil nutrient regimes recognized in this
study (poor, medium, rich, very rich). Previous application of N fertilizer did
not appear to change soil N status sufficiently to alter the classification.
Both discriminant and cluster analyses consistently
differentiated the soil nutrient regimes using exchangeable Mg and mineralizable N in forest floor plus mineral soil. The
consistency of these groupings suggests that important differences between the
nutrient regimes could be identified using soil properties alone.
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40. Karl, M.G. and P.S. Doescher. 1993. Regulating competition on conifer
plantations with prescribed cattle grazing. Forest-Science 39(3): 405-418.
Keywords: release treatments
manual release
stand conditions
tree physiology
soil properties
Abstract: On conifer
plantations, competitive understorey vegetation often
retards growth and establishment of tree seedlings. Livestock grazing is one
method of controlling the understorey vegetation and
increasing the availability of site resources to tree seedlings. It was
hypothesized that prescribed cattle grazing ameliorates water stress of young
tree seedlings by reducing root growth of competing understorey
species. On a Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus
ponderosa) plantation in SW Oregon planted in 1986, seedling water stress was evaluated using
the pressure chamber technique and gravimetric soil water determinations in
1986-89. Root growth of orchardgrass (Dactylis glomerata), the major understorey competing species, was quantified in 1988 and
1989 using the root periscope/mini-rhizotron
technique. Seedling water stress levels during spring and summer were similar
in cattle-grazed areas and ungrazed areas in 1986 to
1988, but in summer 1989, water stress was reduced significantly in the grazed
area. Soil water content was higher in the grazed area in 1989, especially at
the 10-20 cm soil depth. End of season (July) orchardgrass
root growth in grazed plots was 18% less in 1988 and 15% less in 1989 than root
growth in ungrazed plots. It is concluded that
repeated cattle grazing of orchardgrass reduced transpirational surface area and root growth sufficiently
to increase soil water availability to tree seedlings. Thus, prescribed cattle
grazing on conifer plantations can enhance seedling physiological status by
acting as a regulator of above- and belowground competition.
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41. Lavender, D.P. and R.B. Walker.
1981. Nitrogen and related elements in nutrition of forest trees. In
Proceedings: Forest Fertilization Conference, University of Washington, Seattle, Washington, USA. Eds. S.P. Gessel,
R.M. Kenady and W.A. Atkinson. pp. 15-22.
Keywords: fertilization
tree physiology
soil properties
mycorrhizal response
Abstract: This
paper discusses the principal inorganic ions used by forest trees and their
respective roles in tree physiology, their common range of concentration in
coniferous foliage, and the general symptoms associated with their deficiency.
The factors governing effective concentrations of each ion at an active
metabolic site are redistribution or internal nutrient cycling, nutrient
uptake, and soil status (temperature, moisture, and concentration of each
nutrient). Also described are endogenous patterns of nutrient storage and
translocation, and the possible effects of fertilizers upon them and upon the
mechanisms of ion uptake, especially the effect of pH change associated with
urea applications upon the mycorrhizal complement of
western hemlock (Tsuga heterophylla).
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42. Little, S.N. and D.R. Waddell.
1987. Highly stocked coniferous stands on the Olympic Peninsula: chemical
composition and implications for harvesting strategy. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-384. 29 p.
Keywords: site preparation
mechanical preparation
soil properties
Abstract: An
assessment is presented of macronutrients and their distribution within highly
stocked, stagnant stands of mixed conifers on the Quilcene
Ranger District, Olympic National Forest, northwest Washington, USA. These stands consisted of predominantly three species:
western hemlock (Tsuga heterophylla),
coast Douglas fir (Pseudotsuga menziesii
var. menziesii), and western redcedar
(Thuja plicata).
Preliminary investigation suggested that the living crown contained a small
portion of the nutrient capital on the site. Extracting this material from the
site during harvest or site preparation should not pose a threat to future
production of biomass. Bioassays suggested that no macronutrients were
deficient for growth of Douglas fir seedlings. However, care should be taken
during harvest and site treatment to protect the nutrient capital in dead
material and in the forest floor.
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43. Maguire, D.A. 1994. Branch mortality and potential litterfall
from Douglas-fir trees in stands of varying density.
Forest-Ecology-and-Management 70(1/3): 41-53.
Keywords: thinning
wood quality
soil properties
Abstract: Differential
crown recession and crown development among stands of differing density suggest
that an opportunity may exist to control the input of fine woody litter into
the system by manipulating stand density. The objective of this study was to
measure the rate of branch mortality among stands of differing density and to
estimate the range in total per hectare necromass
inputs. Although litter traps are reliable for estimating per hectare rates of litterfall, branch mortality dating on sectioned stems uniquely
allows assessment of several other litterfall
components: (1) individual tree contributions to total litterfall;
(2) the amount of branch material released by mortality, regardless of whether
the branches are shed to the forest floor; (3) the distribution of basal
diameters characterizing the litterfall from a given
tree and stand. Twenty-four trees were felled and sectioned on permanent plots
that were part of a silvicultural study of Douglas
fir (Pseudotsuga menziesii)
stand density regimes, in Umpqua National Forest, near Tiller, Oregon. Whorl branches were dissected out of bole sections to
determine the dates of mortality, and a branch biomass equation was applied to
estimate potential rate of litterfall. Periodic
annual rates were expressed in four ways: (1) number of branches per tree; (2)
mass of branches per tree; (3) mass of branches per unit of crown projection
area; (4) mass of branches per hectare. For the growth periods investigated,
larger trees and trees growing on denser plots tended to release a greater necromass through branch mortality. Average branch basal
diameter generally decreased with increasing stand density. Annual branch
mortality ranged from 33 to 430 g m-2 crown projection area for individual
trees, and from 236 to 1035 kg ha-1 for individual plots. These rates
approached the low end of the range of previously published fine litterfall rates for Douglas fir. Rates on these plots were
relatively low owing to the temporary delay in crown recession imposed by
artificial thinning. A conceptual model of branch litter dynamics is presented
to depict consistencies with crown development among stands managed under
different density regimes.
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44. Miller, R.E., D.H. McNabb and J.
Hazard. 1989. Predicting Douglas fir growth and response to nitrogen
fertilization in western Oregon. Soil-Science-Society-of-America-Journal 53(5): 1552-1560.
Keywords: fertilization
growth
soil properties
stand conditions
Abstract: The objective
of this study was to determine the efficacy of various stand (site index, age,
and relative density), climatic (total precipitation, average daily solar
radiation), site (elevation, soil depth, and available water-holding capacity),
and soil-test variables (anaerobically mineralized N,
total N, organic matter, and C:N ratio) to predict
relative and absolute response of Pseudotsuga menziesii stands to a single application of 224 Kg/N ha as
urea. The core equation with stand variables accounted for 70% of residual
variation in average annual volume growth. Predicting response of fertilized
stands proved much less precise. The best core equation explained 37% of the
residual variation for average percentage response in volume growth and
explained less variation in absolute response in both volume and basal area. Of
the site, climatic, and soil-test variables, C:N ratio
in the surface soil was the only one that significantly increased precision of
the core equations. The best combined equation explained 46% of the variation
in percent volume response. The anaerobic N mineralization test failed to make
a significant contribution to the core equation and had a lower correlation
with response than did the C:N ratio. Stand variables
remain the most reliable predictors of fertilizer response in this region; any
improvement from including soil data for N or organic matter is not justified
because of their additional cost.
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45. Miller, R.E., E.L. Obermeyer and H.W. Anderson. 1999. Comparative effects of precommercial thinning, urea fertilizer, and red alder in a
site II, coast Douglas-fir plantation. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-513. ii + 25 p.
Keywords: fertilization
thinning
precommercial thinning
growth
yield
tree/stand health
soil properties
Abstract: The
number of red alder (Alnus rubra)
trees retained with 300 Douglas-fir (Pseudotsuga menziesii) per acre was varied on a high-quality site in
coastal Oregon. Alder densities of 0, 20, 40, and 80 per acre were
tested. A fifth treatment eliminated nitrogen-fixing alder, but substituted
nitrogen fertilizer. Treatment 6 had neither thinning nor alder control.
Treatments were randomly assigned within each of three blocks in a 9-year-old
plantation. Stand density was reduced within 15 of these 18 experimental units.
Surplus conifers were cut, but surplus red alder were controlled by the
"hack-and-squirt" method. Because numerous trees of other species
regenerated naturally, combined density of all species before thinning ranged
from 1400 to 5700 trees per acre. Subsequent 17-year change in number, average
height, basal area, and volume of Douglas-fir were compared. Retaining
20, 40, or 80 alder per acre reduced numbers of associated Douglas-fir by about
10, 17, and 23 percent, respectively. In pure Douglas-fir plots, gross
volume growth was similar for non-fertilized and fertilized plots, indicating
no measurable benefits of additional nitrogen. In mixed stands, red alder
reduced yield of associated Douglas-fir, but not yield of combined species.
Similar comparisons are needed at other locations, especially those with known
nitrogen deficiency.
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46. Miller, R.E., D.L. Reukema and H.W. Anderson. 2004. Tree growth and soil
relations at the 1925 Wind River spacing test in coast Douglas-fir. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Paper PNW-RP-558. iii + 41 p.
Keywords: planting operations
growth
soil properties
Abstract: The
1925 Wind River (Washington, USA) spacing test is the earliest field trial
seeking to determine the most appropriate spacing for planting Douglas-fir (Pseudotsuga menziesii). Spacing
treatments were not replicated, although individual spacings
were subsampled by 2 to 4 tree-measurement plots.
Previously, greater growth occurred at the wider spacings
(10 and 12 ft) than at the closer spacings (4, 5, 6
and 8 ft). We considered three possible explanations: (1) close spacing
eventually retarded growth, (2) soil quality may be better in the 10- and 12-ft
spacings than at closer spacings,
and (3) tree spacing and soil quality combined affected growth. To test these
explanations, we measured and mapped several site factors (topographic relief,
depth to bedrock, and soil properties), and related these factors to tree and
stand growth. We infer from the strong correlation between spacing and soil
variables that the influence of soil and spacing cannot be separated;
differences in soil depth and available water capacity confound spacing effects
and vice versa. Because soils in the wider spacings
were generally deeper and had more available water capacity than do soils in
the closer spacings, we conclude that some of the
superior tree growth attained in the 10- and 12-ft spacings
is due to more favourable soil conditions. Visual
comparisons of tree size, however, suggest that spacing is probably the
stronger factor affecting tree growth at this location.
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47. Minore,
D. 1986a. Effects of site preparation on seedling growth: a preliminary
comparison of broadcast burning and pile burning. Pacific-Northwest-Research-Station,-USDA-Forest-Service Research-Note PNW-RN-452. 12 p.
Keywords: site preparation
prescribed fire
growth
soil properties
Abstract: In
studies in SW
Oregon, measured and
potential heights were similar for 5-yr-old planted seedlings of Douglas fir (Pseudotsuga menziesii) on areas
that had been broadcast burned. Measured heights were less than potential
heights on most of the pile-and-burn plantations, suggesting that site quality
is damaged by this site preparation method.
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48. Minore, D. and H.G. Weatherly. 1990. Effects of site preparation
on Douglas-fir seedling growth and survival.
Western-Journal-of-Applied-Forestry 5(2): 49-51.
Keywords: site preparation
mechanical preparation
prescribed fire
growth
tree/stand health
soil properties
Abstract: The
effects of 5 site preparation treatment combinations (A: cable yarding + broadcast burning - B: tractor yarding + broadcast burning - C: machine piling + broadcast
burning - D: machine piling + off-site burning - and E: machine piling +
off-site burning + tilling) on Douglas fir (Pseudotsuga
menziesii) growth and survival were studied in
1984-87. Seedling height, potential seedling height, survival percentages,
soil-penetration resistances, and occurrence of visible soil humus were
evaluated on 149 progeny-test plantations in western Oregon. Survival was not improved by mechanical site preparation
(survival at 5 years was 84.8% for treatment A, 73.7% for C and 78.1% for E).
Seedlings grown on compacted soils with low humus, associated with piling slash
off site, did not grow as tall during their first 5 years as seedlings grown on
similar sites where slash had been broadcast-burned (height 77 cm for
treatments D and E, compared to 93 cm for A). Mechanical site preparation was
not essential for Douglas fir survival, as long as competing vegetation is
controlled. Increased soil compaction, loss of humus, and reduced 5 year height
growth associated with mechanized slash removal indicated detrimental effects
on site quality as well as tree growth.
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49. Mitchell, A.K., H.J. Barclay, H. Brix, D.F.W. Pollard, R. Benton and R. DeJong.
1996. Biomass and nutrient element dynamics in Douglas-fir: effects of thinning
and nitrogen fertilization over 18 years. Canadian-Journal-of-Forest-Research
26(3): 376-388.
Keywords: fertilization
thinning
precommercial thinning
carbon allocation
tree
physiology
growth
soil properties
Abstract: The
effects of thinning (two-thirds of basal area removed) and N fertilizer (448 kg
N/ha as urea) on biomass and nutrition of a 24-year-old Douglas fir (Pseudotsuga menziesii) stand at Shawnigan Lake, British Columbia, were studied over 18
years. At years 0, 9, and 18 after treatments, the aboveground biomass and N,
P, K, Ca, and Mg contents of stemwood, stem bark,
foliage, and dead and live branches were determined (kg/ha), and increments in
these properties (kg/ha per year) were calculated for the 0-9 and 9-18 year
periods. Foliar biomass was increased by both treatments during the first
period and also by thinning in the second period. Aboveground net primary
production (ANPP) per unit of foliage biomass (foliage efficiency) was
increased by treatments in the 0-9 year period. The combined effects of
increased foliage mass and foliage efficiency resulted in increased total
biomass production. Thinning and fertilizer application increased the uptake of
all elements except for P with fertilizer. This increase may have contributed
to the long-term increase in stem growth. Retranslocation
of elements before foliage shedding was important for tree nutrition, but was
not improved by fertilizer during the 9-18 year measurement period. The
efficiency of N use in dry matter production (ANPP/unit of N uptake) was
decreased by fertilizer. This implied that poor sites would respond to
fertilizer better than rich sites.
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50. Nason, G.E., D.J. Pluth
and W.B. McGill. 1988. Volatilization and foliar recapture of ammonia following
spring and fall application of nitrogen-15 urea to a Douglas-fir ecosystem.
Soil-Science-Society-of-America-Journal 52(3): 821-828.
Keywords: fertilization
tree physiology
soil properties
Abstract:
Seasonal effects on the volatilization and vegetal recapture of NH3
following application of pelleted 15N urea at 200 kg
N ha-1 to a 40-yr-old Douglas-fir [Pseudotsuga menziesii] ecosystem were investigated. Volatilization totalled 14 and 0.7% of applied N in spring and autumn,
respectively, and the difference appeared to be related to precipitation
patterns following fertilization. Volatilization was generally enhanced by
small spring rainfalls while depressed by larger autumn rains. The isotopic
abundance of evolved NH3 fluctuated from >90 to <10% of that of the
fertilizer source. These fluctuations reflected the role of precipitation in
the regulation of spatial heterogeneity of urea and urease
in soil. Under spring conditions NH3 was recaptured by potted Douglas-fir
seedlings. Seedlings at 10 cm above the forest floor captured 16 times as much
NH3 as seedlings positioned at the 150-cm elevation. Labelled
N was distributed among seedling tissues in the order: current foliage >
1-year-old foliage > roots which is consistent with anabolic incorporation
and translocation. This mechanism may have a significant role in plant
nutrition when conditions favourable to NH3
volatilization follow urea fertilization.
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51. Nelson, E.E., M.G. McWilliams and W.G. Thies.
1994. Mortality and growth of urea-fertilized Douglas-fir on a Phellinus weirii-infested site in
Oregon.
Western-Journal-of-Applied-Forestry 9(2): 52-56.
Keywords: planting
operations
fertilization
tree/stand protection
growth
tree/stand health
soil properties
Abstract:
Twelve plots were established in 1972 in an 11-yr-old Douglas fir (Pseudotsuga menziesii) plantation
infected with Phellinus weirii,
the cause of laminated root rot. All plots were thinned and either interplanted with red alder (Alnus
rubra) or fertilized at 5- to 10-yr intervals with
urea to determine the effect of nitrogen on tree growth and mortality caused by
P. weirii, or left untreated. Interplanted
alder, however, failed to survive. Mortality was assessed at intervals of 2 to
3 yr. Plots were inventoried (100% cruise) in 1978 and 1990. Growth over 12 yr
appeared better on fertilized than nonfertilized
plots, but the difference was not significant. Mortality caused by the preferential
feeding of black bears [Ursus americanus]
on the inner bark of fertilized trees reduced the overall gain. Mortality
caused by laminated root rot did not differ significantly among treatments.
Three months after the initial application of urea at 448 kg N/ha, soil sampled
to a depth of 30 cm was higher in ammonium and nitrate forms of nitrogen on
fertilized than nonfertilized plots, but increases
were not significant. Numbers of soil bacteria were directly correlated with
soil ammonium content (P = 0.1092). Numbers of aerobic actinomycetes
were inversely correlated with soil nitrate content (P = 0.0398).
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52. Newton,
M. and D.S. Preest. 1988. Growth and water relations
of Douglas fir (Pseudotsuga menziesii)
seedlings under different weed control regimes. Weed-Science 36(5): 653-662.
Keywords: release
treatments
chemical
release
growth
soil
properties
tree
physiology
Abstract:
Growth of Douglas fir (P. menziesii) was increased by
controlling grasses and broadleaved weeds with combinations of 4.4 kg atrazine/ha and 2.2 kg 2,4-D or 2,4,5-T during the first 3
years after planting on a well-drained moist site in the Oregon Coast Range.
The greatest growth occurred if weeds were controlled in the same growing
season that tree seedlings were transplanted to the field; smaller increments
came from second- and third-year weed control. Growth increases attributable to
early weed control continued through the fifth year, indicating that conditions
during establishment strongly influenced later growth. Plots with no herbaceous
vegetation had more available soil water than those with competing vegetation,
and tree seedlings on these plots experienced less water stress. Irrigation in
the third year increased stem diameter of seedlings in that year but had no
effect thereafter. Increases in average seedling stem volume at 5 years after
transplanting were linearly related to the difference in observed xylem
potential during the first three seasons after transplanting and the xylem
potential at which photosynthesis ceased, -2 MPa.
OSU
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53. Newton,
M., D.S. Preest and D.E. White. 1987. Effect of
relieving moisture stress with extended weed control in Douglas-fir. Proceedings-of-the-Western-Society-of-Weed-Science
(Vol.40): 129-130.
Keywords: release
treatments
chemical release
growth
tree physiology
soil properties
photosynthesis
Abstract:
The growth of Douglas fir Pseudotsuga menziesii seedlings was increased during the first 5 years
by controlling grasses and forbs in 7 herbicide regimes during the 1st 3 years,
the effect diminishing with time after planting. Devegetated
plots had more available moisture through the growing season than those with Agrostis tenuis or mixed mixed grass/forb cover dominated
by A. tenuis or Hypochaeris
radicata. Tree moisture stress followed soil moisture
but only after allowing for large fluctuations of diurnal stress. Weed control
relieved moisture stress in trees. P. menziesii
photosynthesis tended to shut down in the region of -2.0 MPa
moisture stress. For the 1st 3 years in a favourable
coastal environment approx. 1700 MPa-h above -2.0 MPa was estimated to be required for survival. Increments
of moisture beyond that would contribute significantly to growth.
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54. Pabst, R.J., J.C. Tappeiner, II and M.
Newton. 1990. Varying densities of Pacific madrone in
a young stand in Oregon
alter soil water potential, plant moisture stress, and growth of Douglas fir.
Forest-Ecology-and-Management 37(4): 267-283.
Keywords: release
treatments
manual release
soil properties
tree physiology
growth
Abstract:
In a study to evaluate the effects of mixed conifer/broadleaf stands
on soil water potential, and Douglas fir (Pseudotsuga
menziesii) moisture stress and growth, Pacific madrone (Arbutus menziesii) and
associated shrub and herbaceous vegetation were thinned to represent the
following range of conditions: high-density madrone
(H) with associated shrubs and herbs controlled; medium-density madrone (M), shrubs and herbs controlled; low-density madrone (L), shrubs and herbs controlled; no madrone (N), shrubs and herbs controlled; and no madrone (U), shrubs and herbs predominate. The study was
carried out in 1985 and 1987 at a 2-ha droughty site in the Klamath Mountains,
SW Oregon, planted in 1979 with 2+0 Douglas fir. Soil water-potential ( psi ) at a depth of 0-30 cm was
consistently higher in treatment N than in all other treatments; in 1987 this
difference was significant (P<0.025). Average psi
in treatment U reached -1.5 MPa (permanent wilting
point) between June and July in both years of the study, whereas in the other
treatments that level was never reached. Soil water conditions were also
relatively severe in treatment H. Predawn plant moisture stress (PMS) of
Douglas fir was significantly (P=0.0001) less in treatment N than in all other
treatments. Seasonal moisture-stress relief (SMSR) of Douglas fir was
significantly related to madrone leaf area index
(LAI) and was greatest in treatment N. Seasonal moisture stress relief of madrone was also significantly correlated with LAI. There
were highly significant linear relationships between both predawn and midday PMS and soil water potential
for Douglas fir and madrone. Results clearly show
that conditions for maximum Douglas fir growth occurred in treatment N. Average
diameter growth of Douglas fir was greatest in treatment N, although not
significantly different from that in treatment U, and least in treatment H. In
1987, Douglas fir growth in diameter, stem basal area, and stem volume was
strongly related to SMSR and madrone LAI, and to a
lesser extent, seasonal soil tension relief.
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55. 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.
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56. Petersen, T.D., M. Newton and S.M. Zedaker.
1988. Influence of Ceanothus velutinus
and associated forbs on the water stress and stemwood
production of Douglas-fir. Forest-Science 34(2): 333-343.
Keywords: release
treatments
chemical release
tree physiology
soil properties
growth
Abstract:
In studies in the central Cascade Mts., Oregon, three regimes were
established in 1978 around individual trees in four 5-yr-old and four 10-yr-old
stands, viz. no treatment (control), elimination of C. velutinus
with 2,4-D or elimination of C. velutinus and forbs
with 2,4-D and glyphosate. Seasonal and diurnal
variation in stem and soil water potentials were measured during 1979. Soil
water potential during late summer was <-1.5 MPa
at depths of 10, 40 and 100 cm on control plots and at depths of 10 and 40 cm
in 5-yr-old stands and 10 cm in 10-yr-old stands in plots where only C. velutinus was eliminated. In the absence of shrubs and
forbs, soil water potential at 100 cm was near field capacity throughout the
season. Predawn stem water potential during late summer was significantly lower
on control plots than on the treatment plots for all 5-yr-old stands and for
two of the 10-yr-old stands. By 1986, tree stems were 2-6 cm larger in basal diam. and 1-2 m taller in the absence of competitors. The
increase in stem size was greater in the stand treated at 5 yr old than in that
treated at 10 yr old. The correlation between growth and water stress suggests
that interspecific competition for soil water during
summer drought is a limiting factor in stemwood
production.
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57. Peterson, C.E., P.J. Ryan and S.P. Gessel.
1984. Response of northwest Douglas-fir stands to urea: correlations with
forest soil properties. Soil-Science-Society-of-America-Journal 48(1): 162-169.
Keywords: fertilization
thinning
growth
soil properties
Abstract:
Replicated forest floor and surface soil (0-15 cm) samples were
obtained from control plots at 160 field installations in western Washington
and Oregon.
Six-year growth responses of thinned and unthinned
Douglas-fir [Pseudotsuga menziesii]
treated with 0, 224, and 448 of urea-N ha-1 were correlated with 18 forest
floor and surface soil properties of the control plots. Forest
floor nitrogen properties were the most highly correlated with various
estimates of response in both thinned and unthinned
stands; these correlations were generally independent of methods used to
estimate response. For unthinned stands, C/N ratios
of both forest floor and surface soil were well correlated with growth response
to fertilizer, whereas for thinned stands, N content (kilograms per hectare) of
the forest floor was consistently correlated with response.
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58. Piatek, K.B.,
C.A.
Harrington and D.S. DeBell. 2003. Site preparation
effects on 20 year survival and growth of Douglas-fir (Pseudotsuga
menziesii) and on selected soil properties.
Western-Journal-of-Applied-Forestry 18(1): 44-51.
Keywords: site
preparation
mechanical preparation
prescribed fire
tree/stand health
growth
soil properties
Abstract:
Long-term effects of site preparation on tree performance and soil
properties are not well known. Five site preparation treatments were evaluated
to determine how they affected survival and growth of Douglas-fir (Pinus menziesii) 3, 10, and 20
years after planting, and soil bulk density, C, N, P, and organic matter
concentrations at 0 to 20 cm soil depth 21 years after planting. The site
preparation treatments were imposed following logging of three harvest units of
old-growth forest on a volcanic soil in southwestern Washington, USA; the units
were logged to leave 17, 38, and 53 tonnes/ha of
woody residue. The site preparation treatments were hand-pile-and-burn,
machine-pile-and-burn, scarification, broadcast burn, and control. Mean
survival ranged from 86% at age 3 to 70% at age 20, and average tree heights at
3, 10, and 20 years were 0.6, 4.1, and 11.7 m. The scarification treatment had
the best growth; at age 20, its average tree was 21% taller, 26% larger in
diameter, and 82% greater in volume than the control. The hand-pile-and-burn
treatment did not differ from the control in tree growth; the
machine-pile-and-burn and broadcast burn treatments were intermediate in their
growth response. Average soil bulk density was 0.74 g/cm3, organic matter
concentration was 118 g/kg, and C, N, and P concentrations were 49, 1.6, and
0.7 g/kg with no significant treatment effects. Site preparation may have
benefited growth of the trees on these units by decreasing competition from
invading and regrowing vegetation, increasing
nutrient availability, or increasing soil temperature.
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59. Prescott, C.E. 1995. Does nitrogen availability control rates of
litter decomposition in forests? Plant-and-Soil 168/169:
83-88.
Keywords: fertilization
soil properties
Abstract:
The effects of increased exogenous N availability on rates of litter
decomposition were assessed in several field fertilization trials. In a jack
pine (Pinus banksiana)
forest, needle litter decomposed at the same rate in the controls and those
plots fertilized with urea and NH4NO3 at 1350 kg N/ha (+or-P and K). Mixed
needle litter of western hemlock (Tsuga heterophylla), western red cedar (Thuja
plicata), and Douglas-fir (Pseudotsuga
menziesii) from plots amended with sewage sludge (500
kg N/ha) lost less weight than the controls. Forest
floor material also decomposed more slowly after amendment with sewage sludge.
Paper birch (Betula papyrifera)
leaf litter treated with either sewage sludge (1000 kg N/ha), pulp sludge, or a
sewage/pulp sludge-mixture decomposed at the same rate as the controls.
Exogenous N availability therefore had little impact on litter decomposition
rates. The influence of endogenous N availability on litter decomposition rates
was studied with a microcosm. Lodgepole pine (Pinus contorta var. latifolia) needle litter collected from trees fertilized at
525 kg NH4NO3-N/ha and green needles were both richer in N (1.56 and 1.9% N, resp.) than needles from control trees (0.33 and 0.88% N, resp.), although all the needles decomposed at the same
rate. It was concluded that N availability alone, either exogenous or
endogenous, did not control litter decomposition rates. Increased N
availability, through fertilization or deposition, in the absence of changes in
vegetation composition, was not considered sufficient to alter rates of litter
decomposition in forests.
Non-OSU Link
60. Prescott, C.E., M.A. McDonald, S.P. Gessel
and J.P. Kimmins. 1993b. Long-term
effects of sewage sludge and inorganic fertilizers on nutrient turnover in
litter in a coastal Douglas fir forest. Forest-Ecology-and-Management
59(1-2): 149-164.
Keywords: fertilization
soil properties
Abstract:
Rates of litter input, decomposition, net N mineralization, and N and
P supply on the forest floor were measured in a 70-yr-old second growth stand
of Douglas fir (Pseudotsuga menziesii)
on a poor site in western Washington
state, approximately 10 yr
after applications of sewage sludge and inorganic fertilizers. Sewage sludge
was applied to three plots at the rate of 6000 kg N/ha, and nitrogenous
fertilizers were applied to two plots at rates of 1082 and 1568 kg N/ha. The
rate of each process in each treated plot was compared with that in an adjacent
control plot. Amounts of N returned in needle litter during 1 yr were greater
on sludged and fertilized plots relative to adjacent
control plots. Decomposition of a standard needle litter was the same on all
plots after a 2-h in situ incubation. Rates of N mineralization during aerobic
incubations of forest floor material were similar in all plots in field
incubations, but smaller rates were measured in material from sludged plots in laboratory incubations. Greenhouse
bioassays with Douglas fir and Sitka
spruce (Picea sitchensis)
seedlings showed greater P supply in forest floor material from sludged plots, but no differences in N supply between any
treatments. Turnover of N in litter was not different 10 yr after fertilization
of this forest with sewage sludge or N fertilizer. There was evidence of
long-term enhancement of P turnover in litter plots treated with sewage sludge.
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61. Prescott, C.E. and L.M. Zabek. 1999.
Decomposition and nitrogen mineralization in forests of British
Columbia: effects of forest
management practices. In Proceedings:
Pacific Northwest
forest and rangeland soil organism symposium; 1998 March 17-19; Corvallis,
OR.
Pacific-Northwest-Research-Station,
USDA-Forest-Service General-Technical-Report PNW-GTR-461. Eds. R.T.
Meurisse, W.G. Ypsilantis,
and C. Seybold. 124-136 pp.
Keywords: planting
operations
fertilization
soil properties
Abstract:
The productivity of most forests in the Pacific
Northwest is limited by the availability of nitrogen.
Nitrogen availability is largely controlled by the rate at which N is recycled
from organic matter, through the processes of decomposition and mineralization.
These processes are controlled by the factors that limit the activities of the
soil organisms involved, particularly temperature, moisture, and the physical
and chemical nature of the organic matter. Forest
management activities may influence each of these factors and thereby affect
rates of decomposition, N mineralization and N availability. The influences of
several common forest management activities on decomposition and N
mineralization were examined in a suite of experiments across British
Columbia, Canada.
Rates of decomposition were compared in forests and adjacent clear felled areas
at 22 sites, and rates were either the same or slower in the felled areas.
Several sites had additional silvicultural treatments
that provide a range of either opening size or removal intensity. Decomposition
rates were not influenced by opening size, but rates of net N mineralization
and nitrification were increased in openings greater than 0.1 ha. Tree species
influences N mineralization in the forest floor, with highest rates occurring
in Douglas-fir and broadleaf species and lowest rates in cedar and pines. The
decomposition rates of foliar litters was
best predicted by its lignin concentration. The influence of managing to
maintain a component of broadleaf species was examined in decomposition
experiments with pure and mixed litter of aspen and spruce, Douglas-fir and
alder, and lodgepole pine, Douglas-fir and paper
birch. There was no effect of mixing litters on their rates of decomposition.
Likewise, N fertilization had no effect on decomposition rates in trials in
coastal Douglas-fir and aspen.
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62. Preston,
C.M., V.G. Marshall, K. McCullough and P.J. Mead. 1990. Fate of 15N-labelled
fertilizer applied on snow at two forest sites in British
Columbia.
Canadian-Journal-of-Forest-Research 20(10): 1583-1592.
Keywords: fertilization
soil properties
Abstract:
Fertilizer was applied on snow in January 1981 at 100 kg N/ha as
(15N)urea, 15NH4NO3 or NH415NO3 to 11-yr-old lodgepole
pine (Pinus contorta var. latifolia) at Spillimacheen in
the British Columbia interior and as (15N)urea (200 kg N/ha) to 13-yr-old
Douglas fir (Pseudotsuga menziesii)
at Green Mountain, a coastal site in British Columbia. Recovery of labelled N after one growing season was determined in soil
and biomass at both sites, and it was also monitored during the growing season
in snow and soil at Spillimacheen. At Green
Mountain,
5.5% of urea N was recovered in tree biomass, 10.8% in understorey
and 33.4% in soil organic N (total recovery 49.7%). Leaching may have
contributed to N losses at Green
Mountain,
but was probably not a direct consequence of the application on snow. At Spillimacheen, total recovery of (15N)urea was 93.3%, with 10.1% in tree biomass, 2.4% in understorey and 80.8% in soil. For 15NH4NO3, recoveries
were 5.3% in tree biomass, 2.9% in understorey and
87.0% in soil, for a total of 95.2%. For NH415NO3, recoveries were 1.9% in tree
biomass, 3.4% in understorey and 39.1% in soil, for a
total of 44.4%. At Spillimacheen, the performance of
15NH4NO3 was comparable to that of urea in tree uptake and soil retention.
There were large losses with the NH415NO3 source, however, probably because of
leaching and denitrification during snowmelt. For
this reason, fertilization with nitrate on snow is not recommended because of
nitrate's susceptibility to leaching, but urea and ammonium sources may be
applied under these conditions.
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63. Preston,
C.M. and R.H. Newman. 1995. A long-term effect of N fertilization on the 13C
CPMAS NMR of de-ashed soil humin
in second-growth Douglas-fir stand of coastal British
Columbia. Geoderma
68(4): 229-241.
Keywords: fertilization
thinning
soil properties
Abstract:
Carbon-13 CPMAS NMR spectroscopy was used to examine long-term effects
of thinning and N fertilization on the humin fraction
of soil organic matter in a second-growth Douglas-fir (Pseudotsuga
menziesii) stand in coastal British
Columbia, Canada.
De-ashed OM-enriched humin
fractions were prepared from three mineral soil horizons of four silvicultural treatments using 1.0M HF accompanied by
removal of ferromagnetic iron particles, and a density separation. With some
exceptions a higher proportion of mass was recovered in the denser, light-coloured fraction, and a higher proportion of C and N in
the less-dense, dark fraction. In all cases, the less-dense fraction was
enriched in total C compared to the original crude humin,
and had a more favourable C:Fe ratio for NMR
spectroscopy. The fraction of observable C was 33-37% for 8 of the samples, but
as low as 7.6% for the remaining four. Carbon-13 CPMAS NMR spectra had typical
features for humins (alkyl C, O-alkyl C, di-O-alkyl C, aromatic C, and carboxyl, ester and amide C).
With fertilization, there was a small but consistent decrease in the ratio of
alkyl to O-alkyl C, regardless of horizon or thinning, indicating a lower
extent of decomposition. Carbon-13 subspectra based
on proton spin relaxation time (T1(1H))
were obtained for one fertilized and one unfertilized sample. Subspectra of the slowly-relaxing (long T1(1H)) domain were dominated by long-chain alkyl C.
For the fertilized sample, the subspectrum of the
fast-relaxing (short T1(1H))
domain had a higher proportion of O- and di-O-alkyl
C, consistent with results from the normal CPMAS NMR spectra. Despite the
uncertainties introduced by the de-ashing treatment
and the low fraction of observable C, 13C CPMAS NMR showed that fertilization
has a long-term effect which is reflected in this humin
fraction.
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64. Price, D.T., T.A. Black and F.M. Kelliher.
1986. Effects of salal understory
removal on photosynthetic rate and stomatal
conductance of young Douglas-fir trees. Canadian-Journal-of-Forest-Research
16(1): 90-97.
Keywords: release
treatments
manual release
photosynthesis
tree physiology
soil properties
growth
Abstract:
Studies were made in a thinned 32-yr-old Douglas fir stand on a
drought-prone site on the E. coast of Vancouver
Island. Four pairs of similar trees were selected and
the salal (Gaultheria shallon)
understorey was removed completely from around one of
each pair. The root zones of each tree were isolated using plastic sheeting
buried to bedrock. Photosynthesis, stomatal
conductance, soil water potential and canopy microclimate were measured
intensively in one pair on 4 clear days during an extended dry period in June
1982. B.a.
increment of the four pairs of trees was measured over 3 growing seasons. To
determine the effect of soil water potential on tree photosynthesis, the same
variables were measured for 3 consecutive days in Aug. 1982 for another tree
initially subjected to a soil water potential of approx. -1.6 MPa, but irrigated to approx. -0.02 MPa
between days 1 and 2. Solar irradiance decreased markedly between days 2 and 3,
thus creating a unique data set. Results showed that removal of the understorey significantly increased rates of photosynthesis
in Douglas fir, both diurnally and seasonally. Photosynthesis was not generally
limited by stomatal conductance unless vapour pressure deficit was high and photon flux density
was saturating. Improved tree growth after understorey
removal was due to the increased soil water potential that increased both
photosynthetic capacity and stomatal conductance.
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65. Prietzel, J., G.L. Wagoner and R.B.
Harrison. 2004. Long-term effects of repeated urea fertilization in Douglas-fir
stands on forest floor nitrogen pools and nitrogen mineralization.
Forest-Ecology-and-Management 193(3): 413-426.
Keywords: fertilization
soil properties
Abstract:
In six Douglas-fir [Pseudotsuga
menziesii (Mirb.) Franco]
stands in the Puget Sound Region in Western Washington/USA, forest floor C and
N pools were quantified on control plots and on plots that had been fertilized
repeatedly with urea 8-30 years ago (total amount of applied N 0.9-1.1 Mg
ha-1). Additionally, net N mineralization and nitrification rates were assessed
in field and laboratory incubation experiments. Forest
floor C/N ratios were decreased on the fertilized plots of all sites compared
to the respective control plots. The decreases were particularly strong at
sites with initial C/N ratios larger than 30. On sites with low productivity (site
index at age 50: <33 m), N fertilization resulted in considerable increases
in forest floor N pools. Net N mineralization and nitrification during 12-week
field incubation was negligible for the unfertilized and fertilized plots of
all except one site (Pack
Forest),
where the stand had been clear-cut 2 years ago. The increases in N
mineralization rates during 12-week laboratory incubation induced by repeated N
fertilization showed an inverse relationship to the time elapsed since the last
fertilizer application, and were generally larger at sites with initial forest
floor C/N ratios >30. For the investigated sites, fertilization effects on
net N mineralization sustained for at least 11 years after the last fertilizer
application. Nitrification correlated strongly with the forest floor pH;
significant formation of NO3- was observed only for O layers with a pH (H2O)
higher than 4.5.
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66. Radwan, M.A. and J.S. Shumway. 1984. Site index and selected soil properties in
relation to response of Douglas-fir and western hemlock to nitrogen fertilizer.
In Forest soils and treatment impacts: Proceedings of the Sixth North
American Forest Soils Conference, Department of Forestry, Wildlife and
Fisheries, University of Tennessee, Knoxville, TN, June 1983. Ed. E.L. Stone. pp. 89-104.
Keywords: fertilization
growth
soil properties
Abstract:
Studies were made in 25 Douglas fir stands in Washington
and Oregon
and in 16 western hemlock stands in Washington.
Site index, total and mineralizable soil N were the
only variables correlated with growth response to N fertilizer by Douglas fir.
Growth response of hemlock was correlated with extractable P/total N in the
soil. Total N and mineralizable S in mineral soil
were highly correlated and showed moderate negative correlations with growth
response of hemlock, but site index was not correlated with response. Results
suggest that site index and soil N seem promising indicators of the response of
Douglas fir to N fertilizer, while extractable P and the P/N ratio may indicate
the response of hemlock. Soil N appears to be more important than soil P in
predicting the response of Douglas fir on the sites studied. Soil S did not
appear to limit the response of either species to N fertilizer and does not
seem promising for estimating the response to N.
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67. Roberts, S.D., C.A.
Harrington and T.A. Terry. 2005. Harvest residue and competing vegetation
affect soil moisture, soil temperature, N availability, and Douglas-fir seedling
growth. Forest-Ecology-and-Management 205(1/3): 333-350.
Keywords: site
preparation
chemical preparation
release treatments
chemical release
soil properties
growth
tree physiology
Abstract:
Decisions made during stand regeneration that affect subsequent levels
of competing vegetation and residual biomass can have important short-term
consequences for early stand growth, and may affect long-term site
productivity. Competing vegetation clearly affects the availability of site
resources such as soil moisture and nutrients. Harvest residues can also affect
the availability of site resources. We examined second and third year seedling
performance of a Douglas fir (Pseudotsuga menziesii) plantation with different vegetation control and
biomass retention treatments on a highly productive site in the coast range of
Washington, USA. Treatments included a bole-only harvest without vegetation
control (BO-VC), a bole-only harvest with complete vegetation control (BO+VC),
and a total tree harvest with complete vegetation control that also included
removal of all coarse woody debris and harvest residues (TTP+VC). The VC
treatment involved: (a) in the first year, broadcast application of Oust and
Accord concentrate applied with a surfactant 2 weeks before planting; (b) in
the second year, a March broadcast application of Atrazine
and a directed spot-spray of Accord Concentrate on the vegetation between rows
in April-May; and (c) in the third year, a March broadcast application of Atrazine and Oust, a direct spot-spray application of
Accord Concentrate, and a spot-spray of Transline
with surfactant on April-May to control persistent shrub species. The study was
conducted to determine if vegetation control and residue retention treatments
affected soil moisture, soil temperature, and apparent nitrogen (N)
availability, and whether these differences in site resources were correlated
with seedling size and growth. In both second and third growing seasons,
volumetric soil moisture at 0-20 cm depth was lowest on plots that did not
receive vegetation control (BO-VC). Seedlings on these plots also had the
lowest diameter and volume growth. In year 2, which was fairly moist, volume
growth on TTP+VC plots was slightly higher than on BO+VC plots. TTP+VC plots
did have lower soil moisture, but soil temperatures were slightly warmer. In
year 3, a drier year, growth was greatest on BO+VC plots, which had
consistently higher soil moisture levels. Apparent N availability in year 3
also varied with vegetation control. Douglas fir foliar N concentrations
averaged 2.3% on the plots where competing vegetation was eliminated,
compared to 1.8% on plots where competing vegetation was not controlled.
Douglas fir foliar N concentrations did not differ between residue retention
treatments, although N concentrations of competing vegetation were higher where
residual biomass was retained. Higher apparent N availability was correlated
with greater seedling growth. Based on the results from years 2 and 3, it
appears that soil moisture, particularly late in the growing season, had the
greatest effect on seedling growth in both years. Available N may also have
played a role, although the effects of N cannot be completely separated from
those of soil moisture. When soil moisture is adequate, it appears that
available N and soil temperature exert greater influence on growth. Vegetation
control and residue retention can influence all 3 of these factors. The
relative importance of each factor may depend on the year-to-year variation in
environmental conditions.
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68. Rollwagen, B.A. 1983. Effects of ammonium and nitrate application on rhizosphere
pH, growth and nutrient uptake by Douglas-fir, Sitka spruce and western hemlock.
Forestry-Abstracts 44(11): 699.
Keywords: fertilization
soil properties
growth
tree physiology
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69. 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.
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70. Sachs, D. and P. Sollins. 1986.
Potential effects of management practices on nitrogen nutrition and long-term
productivity of western hemlock stands. Forest-Ecology-and-Management 17(1):
25-36.
Keywords: thinning
commercial thinning
yield
soil properties
computer modeling
Abstract: The FORCYTE-10 computer model, developed by J.P. Kimmins and K. Scoullar for
Douglas-fir forests in British
Columbia, was modified to
simulate growth and nutrient cycling of coastal western hemlock stands in Oregon.
Initial calibration indicated that predicted yield was extremely sensitive to
the rate of mineralization of soil organic matter (SOM), variation in SOM C/N
ratio with site quality, the soil extractable NO3-/NH4+ ratio, and the
decomposition rate and N mineralization pattern of large and medium-size roots
and woody debris. The predictions suggested that yield and SOM remain stable
under a management system consisting of six successive 90-yr rotations. More
intensive utilization (e.g., shorter rotations, whole-tree harvesting and
commercial thinning) causes depletion of soil and forest floor nitrogen and a
small decline in site productivity in later rotations.
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71. Shumway, J.S. and H.N. Chappell. 1995.
Preliminary DRIS norms for coastal Douglas-fir soils in Washington
and Oregon.
Canadian-Journal-of-Forest-Research 25(2): 208-214.
Keywords: fertilization
thinning
growth
soil properties
Abstract:
The Diagnosis and Recommendation Integrated System (DRIS) has been
used successfully to evaluate interactions between nutrients and fertilizer
response and for diagnosing nutrient deficiency in agricultural crops. This
study used soil tests to develop DRIS norms and evaluate their effectiveness in
coastal Douglas fir (Pseudotsuga menziesii)
forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were
developed using soil test and site index data from 72 soil series that commonly
support Douglas fir in western Washington.
The norms were tested using soil test and stand basal area growth response data
from 20 thinned and 30 unthinned N fertilizer test
sites in coastal Washington
and Oregon.
Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and
448 kg N.ha-1, respectively, when N was identified as the most limiting
nutrient. When N was not the most limiting nutrient, N response averaged 8% and
10% for 224 and 448 kg N.ha-1, respectively. Results were similar in unthinned stands and thinned stands, although response to
fertilizer appeared to be slightly less in unthinned
stands when N was the most limiting nutrient. DRIS correctly classified 25 of
the 33 sites (76%) where N fertilizer increased growth by more than 15%. More
importantly, 13 of the 17 (76%) sites that responded by less than 15% were
correctly identified by DRIS. The results clearly indicate that N fertilizer
response is dependent on the interactions (balance) between soil nutrients at a
given site. Future soil diagnostic work needs to focus on techniques, like
DRIS, that provide an assessment of these interactions.
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72. Strader, R.H. and D. Binkley. 1989.
Mineralization and immobilization of soil nitrogen in two Douglas-fir stands 15
and 22 years after nitrogen fertilization. Canadian-Journal-of-Forest-Research
19(6): 798-801.
Keywords: fertilization
growth
soil properties
Abstract:
Additions of 15N-labelled NH4Cl were used to examine the role of
microbial immobilization in long-term growth response of Douglas fir (Pseudotsuga menziesii)
plantations to N fertilizer treatment. Soil samples were collected in summer
1986 from fertilized (448 or 470 kg/ha N) and nonfertilized
plots at previously established N fertilization experiments near Shawnigan Lake, British Columbia, and the Wind River
Experimental Forest near Carson, Washington. Douglas fir on these sites were reported to still be
responding to N fertilization after 12 and 18 years. Less than 2% of the added
15N was recovered as mineral N after a 14-day laboratory incubation of soil
samples from the fertilized and nonfertilized plots.
This indicates that gross mineralization could be >50x greater than net
mineralization in these infertile soils if the remaining 98% of the added 15N
were all biologically immobilized. Net mineralization was significantly greater
(p <less or =>0.10) in soils from the fertilized plots than in those from
the nonfertilized plots at the Wind
River site. Although the current differences in N
availability did not appear to be related to differences in microbial
immobilization, such large rates of immobilization require further
investigation as a factor in long-term response to fertilization.
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73. Sturrock, R.N., E.J. Phillips and R.G.
Fraser. 1994. A trial of push-falling to reduce Phellinus
weirii infection of coastal Douglas-fir. B.C. Ministry of Forests FRDA-Report 217.
vi + 22 p.
Keywords: tree/stand
protection
economics
tree/stand health
soil properties
Abstract:
In push-falling, whole trees are pushed over by a bucket- and thumb-equipped excavator
then grapple skidded to a landing where root masses are cut off and stems are
bucked into logs. Harvesting of trees and removal of diseased roots is thus
achieved with one stand entry. The productivity and economics of push felling
were evaluated in a second-growth Douglas fir (Pseudotsuga
menziesii) stand in coastal British
Columbia. Results indicated
that costs are comparable to those for conventional harvesting alone and that
push felling can effectively remove infected roots. Before harvest <80% of
the site was undisturbed but disturbed soils occupied 50.6% of the site after
harvest. Changes in total bulk densities were relatively minor.
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74. Thies, W.G., E.E. Nelson and D. Zabowski. 1994. Removal of stumps from a Phellinus weirii infested site
and fertilization affect mortality and growth of planted Douglas-fir.
Canadian-Journal-of-Forest-Research 24(2): 234-239.
Keywords: site
preparation
mechanical preparation
fertilization
tree/stand protection
tree/stand health
growth
soil properties
Abstract:
A field study was established in a 4.9 ha clearcut
on the west slope of the Cascade Range (44 degrees 21'N, 122 degrees 39'W),
Oregon, to evaluate the effects of stump removal (of both infested and
non-infested stumps) and fertilizing with ammonium nitrate on the incidence of
laminated root rot (caused by Phellinus weirii) in Douglas fir (Pseudotsuga
menziesii) seedlings. A 2x4 set of factorial
treatments of stump removal in combination with nitrogen fertilizing was
applied in August 1980 to 0.04-ha circular plots within the clearcut.
Treatments included stump removal (either all stumps removed or the plot left
undisturbed) and broadcast application of ammonium nitrate (0, 336, 672, or
1345 kg N/ha). Diameter at breast height and height of Douglas fir, planted as
2+1 bare root seedlings 4 months after treatment (in January 1981), were
recorded 5 and 9 seasons after outplanting. Soil bulk
density in the upper 20 cm was measured with a single-probe neutron densimeter. Stump removal reduced the number of seedlings
killed by laminated root rot but had no significant effect on seedling growth.
Stump removal increased soil bulk density only 7% as measured 9.7 years after
treatment. Fertilizer increased the growth in diameter at breast height, and
height growth of the seedlings but had no effect on mortality. There were no
significant interactions between fertilizing and stumping treatments. Increased
total soil N could still be detected on fertilized, nonstumped
plots 9.7 years after treatment.
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75. Trofymow, J.A., H.J. Barclay and K.M.
McCullough. 1991. Annual rates and elemental concentrations of litter fall in
thinned and fertilized Douglas-fir. Canadian-Journal-of-Forest-Research 21(11):
1601-1615.
Keywords: fertilization
thinning
soil properties
Abstract:
Overstorey litterfall
(primarily needles) was collected for 15 years (1972-86) within control and
treated plots in a Douglas fir (Pseudotsuga menziesii) stand near Shawnigan Lake, British
Columbia. Treated plots were
thinned or fertilized, or both. Thinned plots had two-thirds of their basal area
removed; fertilized plots were treated with 448 kg N/ha of either urea or
ammonium nitrate, and the
fertilized plots were refertilized at the same rate 9
years later. The annual rate of litterfall in control
plots averaged 1890 kg/ha. In control plots, significant yearly variations were
observed in litterfall mass and concentrations of K,
Mg, and Ca but not N or P. Thinning decreased rates of litterfall
by 80%, but rates returned to control-plot levels after 13-15 years in
unfertilized plots and after 8-10 years in fertilized plots. Fertilizer
treatment without thinning depressed litterfall in
the year of treatment but increased the rate by 20-80% in subsequent years. Litterfall N concentrations increased by 40-80% the year of
fertilizer treatment and then began decreasing 3-6 years later. Nitrogen
fertilization reduced litterfall P, K and Mg
concentrations for 8, 4 and 1 year(s), respectively, following fertilizer
treatment. The effects were greater in ammonium nitrate plots than in urea
plots. Rates of litterfall correlated poorly with
stand density but well with basal area and stemwood
increment. Correlations with the latter two variables varied with time and
treatment.
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76. Turner, J. 1982. The mass flow
component of nutrient supply in three western Washington
forest types. Acta Oecologica
Oecologia Plantarum 3(4):
323-329.
Keywords: fertilization
soil properties
growth
tree physiology
Abstract:
[See FA 37, 7318; 38, 5185; 39, 1857; 41, 3566; 44, 4913] The mass flow component of nutrient
uptake, defined as the product of bulk soil sol. concn.
and water uptake was
calculated for a series of forest stands from previously published data. Stands
were of Douglas fir of varying ages and nutrient status (both undisturbed and
fertilized), red alder (Alnus rubra),
Pacific silver fir (Abies amabilis)
and beech (Fagus sylvatica).
Uptake of N, P, K, and Mg increased, and Ca uptake remained stable as stands
matured; the proportion of nutrient uptake fulfilled by mass flow tended to
increase with stand age. Fertilizer application gave various results related to
changes in soil sol. nutrient concn. and tree growth. The stands of red
alder and silver fir showed variable patterns between nutrients and these are
discussed in relation to soil nutrients, productivity and previously
unpublished data.
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77. Turner, J., D.W. Johnson and M.J. Lambert. 1980. Sulphur
cycling in a Douglas-fir forest and its modification by nitrogen application. Acta Oecologica Oecologia Plantarum 1(1): 27-35.
Keywords: fertilization
soil properties
Abstract:
[See FA 39, 1857] In a study of a 42-yr-old nitrogen-deficient stand
in Washington State, subject to acid rain and elevated inputs of S, excess S
was found to be stored and cycled as SO4. A nitrogen (urea) fertilizer
experiment reported previously resulted in the incorporation of foliar SO4 into
organic S and a reduction in concn. of litterfall
SO4. Nitrogen stress induced in the same experiment by addition of carbohydrate
(sucrose and sawdust) to the forest floor resulted in greater return of SO4 via
litterfall.
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78. Velazquez-Martinez, A. and D.A. Perry. 1997. Factors influencing
the availability of nitrogen in thinned and unthinned
Douglas-fir stands in the central Oregon Cascades.
Forest-Ecology-and-Management 93(3): 195-203.
Keywords: fertilization
thinning
soil properties
Abstract:
Soil N mineralized during 7-day anaerobic incubation at 40 degrees C (available
N) was compared at 2 soil depths and correlated with soil and site factors in
Douglas fir [Pseudotsuga menziesii]
stands with different combinations of thinning and multinutrient
fertilizing. Available N expressed either on an area basis (kg ha-1) or on a
concentration basis (mg kg-1) at the 2 depths did not vary significantly by
stocking density, treatment, or density-treatment interaction. There was a
significant difference between the soil depths, averaging 39 mg kg-1 at 0-20 cm
depth, and 20 mg kg-1 at 20-40 cm depth. Available N was positively correlated
with total soil N, exchangeable Ca, and adjusted aspect (the former 2 factors
accounting for 46% of the total variation), and negatively with rock content
and slope steepness. Stand density had no effect.
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79. Wang, X. and D. Zabowski. 1998. Nutrient
composition of Douglas-fir rhizosphere and bulk soil
solutions. Plant-and-Soil 200(1): 13-20.
Keywords: nursery
operations
nursery fertilization
soil properties
Abstract:
A study was conducted during 1995-96 at Weyerhaeuser Rochester
Seedling Nursery and the White River District of the Weyerhaeuser Tree Farm,
Washington, to investigate the nutrient composition of Douglas-fir [Pseudotsuga menziesii] rhizosphere soil solution in soils belonging to the Nisqually and Pitcher soil series, respectively, and to
compare rhizosphere solution with that of bulk soil
solution. Fertilized (urea, ammonium sulfate, calcium nitrate, and triple superphosphate) and unfertilized Nisqually
soils were also compared. Soil solutions were collected using centrifugation.
Nutrient concentrations in the rhizosphere solutions
were typically higher than that of bulk soil solutions when no fertilizer was
applied, but differences in the concentrations of nutrients between the rhizosphere and bulk soil solutions were masked by the
addition of fertilizers. With a higher concentration of NH4 relative to NO3 in
the rhizosphere soil solution, the solution pH of the
rhizosphere was lower than that of the bulk soil, but
with a lower concentration of NH4 relative to NO3, the solution pH of the rhizosphere was higher than that of the bulk soil solution.
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80. Wang, Z., M. Newton and J.C. Tappeiner,
II. 1995. Competitive relations between Douglas-fir and Pacific madrone on shallow soils in a Mediterranean climate.
Forest-Science 41(4): 744-757.
Keywords: release
treatments
manual release
soil properties
growth
Abstract:
A large area of Pacific
Coast
forests is characterized by shallow soil, with negligible rainfall in the
growing season. The availability of bedrock water and its effects on growth and
ecophysiology of 11-yr-old planted Douglas fir (Pseudotsuga menziesii) and
sprouting Pacific madrone (Arbutus menziesii) was studied. The study was carried out at 3
regulated densities (0, 330 or 1322 clumps/ha) of madrone
sprouts on shallow (<50 cm) residual soils in the Klamath Mts of SW Oregon. Total bedrock water depleted from March
to September, as observed in drill holes by neutron probe, and did not suffer
significantly among the 3 densities of madrone
sprouts. However, cover in plots with the highest density of madrone depleted 50 mm of water from the 1.5 m layer by
June, whereas vegetation on lower density treatments withdrew 15-28 mm by June,
with later withdrawal distributed more uniformly through the growing season. Madrone density significantly affected basal diameter and
height growth of Douglas fir. Madrone was
consistently taller than Douglas fir in all plots. The height of 11-yr-old madrone sprout clumps (424-465 cm) did not differ
significantly among densities. Madrone leaf area
index and biomass were higher at the high density of madrone
than at medium density. Physiological advantages and rooting habits of madrone give it a competitive advantage over Douglas fir at
this site, that it might not
have if bedrock did not provide the principal water reservoir for summer
growth.
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81. Wass, E.F. and R.B. Smith. 1997. Impacts
of stump uprooting on a gravelly sandy loam soil and planted Douglas-fir
seedlings in south-coastal British
Columbia. Pacific-Forestry-Centre,-Canadian-Forest-Service Information-Report BC-X-368.
vi + 15 p.
Keywords: site
preparation
mechanical preparation
tree/stand protection
soil properties
stand conditions
growth
Abstract:
Studies to determine levels and impacts of soil disturbance caused during
root-disease control by stump removal were initiated on a cutover on southern Vancouver
Island immediately prior to the control operation and
the establishment of a plantation of Douglas-fir (Pseudotsuga
menziesii). Soil surface condition was assessed on
the stumped area. Soil disturbance was measured at 699 planting spots.
Vegetation development was assessed at 10% of the spots. Of all planting spots,
180 were undisturbed soil, 277 deposits and 242 gouges. The soil, a gravelly
sandy loam, increased naturally in soil density with depth from 1.05 t/msuperscript 3 at the surface
to over 1.60 t/msuperscript 3 at depths more than 40
cm. Disturbance did not significantly increase soil density. Unlike previous
studies of this nature, ease of soil penetrability was increased by the stump
uprooting disturbance and vegetation development was not greatly dissimilar
between disturbed and undisturbed soil. The relatively low soil impacts were
attributed to the ability of the excavator to pile stumps without pushing
topsoil, and the low site sensitivity to compaction. These low impacts on soil
and reduced vegetative competition on disturbed soil resulted in tree growth
rates which were significantly greater after 10 years on deposits (12% in
height and 18% in diameter) and gouges (6% in height and 8% in diameter) than
on undisturbed soil.
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