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.
OSU Link
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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.
Non-OSU
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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