1. DeBell, D.S. and T.C. Turpin. 1989. Control of red alder by
cutting. Pacific-Northwest-Research-Station,-USDA-
Keywords: release treatments
manual release
stand
conditions
Abstract: Effects
of tree age, month of cutting, and height and angle of the cut on sprouting of
red alder (Alnus rubra)
stumps were evaluated in a study designed to develop an effective method for
controlling red alder in Douglas fir (Pseudotsuga menziesii) plantations in the Oregon Coast Range.
2.
Keywords: release treatments
chemical release
manual release
growth
soil
properties
Abstract: Harsh
environments on many harvested sites in
3. Harrington, T.B. and
J.C. Tappeiner, II. 1997. Growth responses of young
Douglas-fir and tanoak 11 years after various levels of hardwood removal and understory suppression in southwestern
Keywords: release treatments
manual release
growth
tree/stand
health
Abstract:
4. Harrington, T.B., J.C.
Tappeiner, II and T.F. Hughes. 1991. Predicting
average growth and size distributions of Douglas-fir saplings competing with
sprout clumps of tanoak or Pacific madrone.
New-Forests 5(2): 109-130.
Keywords: release treatments
manual release
growth
stand
conditions
Abstract: Average
growth and size distributions of 3- to 6-year-old (in 1983) Douglas fir (Pseudotsuga menziesii) saplings
in three plantations in SW Oregon were studied for 7 years (1983-1989) after
thinning of associated sprout clumps of tanoak (Lithocarpus
densiflorus) or Pacific madrone
(Arbutus menziesii); in some cases shrubs and herbs
were also suppressed. Biologically based nonlinear equations explained 66, 90,
and 53% of variation in average annual increment of Douglas fir height,
diameter-squared, and crown cover, respectively. Equations for annual increment
of crown cover of broadleaved and understorey
vegetation explained only 10 to 12% of the variation, because these parameters
exhibited a high degree of variability. Model simulations demonstrated that,
for the same initial levels of cover, tanoak had faster rates of crown cover
growth than madrone and also caused greater
limitations in Douglas fir growth. Suppression of shrubs and herbs increased
growth of Douglas fir only when broadleaved species were absent. Weibull functions adequately described size distributions
for Douglas fir in 92% of individual-tree data sets. Regression functions of
broadleaved crown cover and average Douglas fir size explained 51, 93, and 24%
of variation in the Weibull A, B, and C parameters,
respectively. Model simulations with predicted Weibull
parameters demonstrated that broadleaved competition caused a positive skewing
in size distributions for height and stem diameter of Douglas fir.
5. Harrington, T.B., R.G.
Wagner, S.R. Radosevich and J.D. Walstad.
1995. Interspecific competition and herbicide injury
influence 10-year responses of coastal Douglas-fir and associated vegetation to
release treatments. Forest-Ecology-and-Management 76(1/3): 55-67.
Keywords: release treatments
chemical release
manual release
growth
tree/stand health
tree physiology
stand
conditions
Abstract:
Responses of competing vegetation and planted Douglas fir (Pseudotsuga
menziesii var. menziesii)
were studied for 10 years after six herbicide and manual release treatments in
the Washington and Oregon Coast Ranges. Studies were installed in six 2- or
3-yr-old plantations, with Douglas fir densities of 988 to 1482 plants/ha at
time of planting and 721 to 1282/ha 2 to 3 years late. Research objectives were
to quantify regional, long-term responses of vegetation (Douglas fir and
non-coniferous species) to various levels of competition, light and soil water
availability, and intensity versus importance of factors influencing Douglas
fir growth. Three treatments reduced shrub cover relative to the untreated
check: triclopyr in year 1, glyphosate
in years 1-5, and repeated control (via several herbicide applications) in
years 1-10. Reductions in woody cover from glyphosate
stimulated increases in herb cover in years 3 and 5, while repeated control
reduced herb cover in years 1, 2 and 5. Through year 10, Douglas fir survival
(86-99%) varied little among treatments. Visual symptoms of herbicide injury to
Douglas fir from triclopyr (45% of trees) and glyphosate (17% of trees) were associated with 0.1-0.2 m
reductions in first-year height. After adjusting for tree size, Douglas fir
growth in stem basal area 2 years after triclopyr was
less than that of the untreated check, suggesting prolonged effects of
herbicide injury. Because it sustained low levels of interspecific
competition, caused minimal tree injury, and prevented overtopping cover from
red alder (Alnus rubra),
repeated control was the only treatment in which Douglas fir size (9.8 m height
and 21 cm basal diameter in year 10) significantly exceeded (P<less or
=>0.02) that of the untreated check (7.8 m height and 12 cm diameter).
6.
Keywords: release treatments
manual release
stand conditions
tree physiology
growth
Abstract: In
7. Jaindl,
R.G. and S.H. Sharrow. 1988. Oak/Douglas-fir/sheep: a
three-crop silvopastoral system. Agroforestry-Systems
6(2): 147-152.
Keywords: planting operations
release treatments
manual release
tree/stand health
growth
Abstract: A small
scale agroforestry study started in 1952 was
revisited in 1985 to evaluate the long-term influence of site preparation and
grazing on tree growth and survival in a system with Douglas fir, white oak (Quercus garryana) and sheep. In
1952-53, 2-yr-old Douglas fir seedlings were planted at the rate of 2500
trees/ha under 3 levels of site preparation: (1) no treatment; (2) oak thinned
by 50%; and (3) oak clear felled. From 1954 to 1960, yearling ewes grazed half
of each of the 3 thinning treatments for 3-4 wk each spring. The conifers were
undisturbed since grazing was discontinued in 1960. Survival of planted
conifers averaged 64% in 1985 and did not vary among either site preparation or
grazing treatments. From 1964 to 1985, trees on the thinned and clear felled
plantations grew an av. ht. of 1060 and 990 cm, respectively, compared with 900
cm on the unthinned plantation. D.b.h.
averaged 3.8 and 5.6 cm greater on thinned or clear felled plantations,
respectively, than on the unthinned control by 1985.
Conifers on grazed plantations had increased ht. and d.b.h.
growth during the first 12 yr of plantation life, averaging 63 cm taller and
0.7 cm greater in d.b.h. than the ungrazed
plots by 1964. By 1985 the difference in ht. (122 cm) and d.b.h.
(1.0 cm) between grazed and ungrazed plantations was
not statistically significant. These data suggest that although site
preparation can positively influence conifer growth, total clear felling is no
better than thinning oaks. Furthermore, proper grazing can increase ht. and d.b.h. growth of the conifers during and immediately after
the grazing years.
8. 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
9. Knapp, W.H., T.C.
Turpin and J.H. Beuter. 1984. Vegetation control for
Douglas-fir regeneration on the
Keywords: planting operations
site preparation
chemical preparation
mechanical preparation
prescribed fire
release treatments
chemical release
manual release
growth
yield
economics
Abstract: Records
from 324 plantations in
10.
Keywords: release treatments
chemical release
manual release
growth
tree
morphology
Abstract: Height-age
and height-diameter models for plantations of young Douglas fir (Pseudotsuga menziesii var. menziesii) were examined in relation to vegetation
management treatments. The models were developed from 10 years of measurements
in a competition release study installed on six sites in the Coast Ranges of
Oregon and Washington. Analysis of height growth patterns for dominant trees
indicated significant differences between the total vegetation control
treatment and operational release treatments or no treatment. The resulting
height-age function depicted exponential growth patterns for the total vegetation
control treatment and nearly linear patterns for the operational release
treatment and no treatment. The height-diameter function was compatible with
dominant height growth and quadratic mean diameter prediction functions.
Different height-diameter curve shapes were associated with total vegetation
control and the operational release and no treatments. The resulting function
implied that Douglas fir trees of a given diameter and age were slightly taller
when under interspecific competition, especially for
trees with smaller diameters. The height-age and height-diameter functions may
be used in conjunction with diameter distribution or stand table projection
models developed for these data to predict dynamics and stand structure in
young Douglas fir plantations.
11.
Keywords: release treatments
manual release
chemical release
growth
tree
morphology
Abstract: A
parameter recovery procedure for the Weibull
distribution function, based on diameter percentiles, was modified to
incorporate the effects of competing vegetation in young Douglas fir (Pseudotsuga menziesii var. menziesii) plantations. The procedure was tested using data
from sites in the Coast Ranges of Oregon and Washington and in the
12. McDonald, P.M. and
G.O. Fiddler. 1993. Feasibility of alternatives to herbicides in young conifer
plantations in
Keywords: genetic tree improvement
site preparation
prescribed fire
release treatments
manual release
chemical release
growth
economics
Abstract: A
research programme (involving 40 studies) was started
in 1980 to compare the effectiveness and cost of various vegetation management
techniques used for enhancing growth of 1- to 3-yr-old conifer (Pseudotsuga menziesii, Pinus ponderosa, P. jeffreyi, Abies magnifica and A. concolor var. lowiana)
plantations in California. The studies were ended after 10 yr when competition
became intraspecific. The techniques used included
direct methods such as manual manipulation, mulching, herbicides (Garlon 3A [triclopyr], 2,4-D or Velpar [hexazinone]), and grazing
for releasing conifer seedlings from undesirable vegetation, and several silvicultural practices (broadcast burning, group
selection, genetically improved seedlings) that serve as indirect methods for
reducing or avoiding vegetation problems. Manual release and mulching were
effective but expensive. Herbicides were effective, applicable to almost all
plant communities, and relatively inexpensive. Grazing was good for cattle and
sheep, but did not significantly enhance conifer seedling growth. Silvicultural control of weeds was promising, but there was
not enough information to evaluate feasibility. It was concluded that in most
instances, forests cannot be managed economically without herbicides, if the
objective is to grow seedlings at the potential of the site and the plant
community includes sprouting broadleaves and shrubs or rhizomatous forbs and
ferns. If the objective is to create a forest with several age-classes and
variable structure, but with slower seedling growth, longer rotations, and less
species diversity in early seral stages, then it is
possible to accomplish this using other vegetation management techniques.
13. McDonald, P.M. and
G.O. Fiddler. 1996. Development of a mixed shrub-tanoak-Douglas-fir community
in a treated and untreated condition. Pacific-Southwest-Research-Station,
USDA-Forest-Service Research-Paper PSW-RP-225. iv + 16 p.
Keywords: release treatments
manual release
chemical release
tree/stand health
growth
tree morphology
stand conditions
economics
Abstract: On a
medium site in northern California, a tanoak (Lithocarpus
densiflorus)-mixed shrub community in a Douglas fir
plantation was given several treatments (manual release two and three times, a
combination chainsaw and cut surface herbicide (Garlon
3A [triclopyr]) treatment, two foliar herbicides
(2,4-D or Garlon 4), and a tank mix of the two
herbicides) to study its development in both a natural (control) and treated
condition. The herbicides were each applied twice. Survival of planted Douglas
fir (Pseudotsuga menziesii)
seedlings was recorded for 11 years and growth was quantified for 9 years after
the last treatment application. In addition to Douglas fir, data are presented
individually for the two most abundant species (tanoak and snowbrush, Ceanothus velutinus var. hookeri), for greenleaf manzanita (Arctostaphylos patula), and for the hardwood tree and shrubs combined. At
the study's end in 1992, combined vegetation in the control had a mean density
of 1800 plants/acre, foliar cover of 23 700 ftsuperscript
2/acre, and height of 11.2 ft. In contrast, combined tree and shrubs in the
most effective treatment for controlling them (cut and spray Garlon 3A) had a mean density of 150 plants/acre, foliar
cover of 150 ftsuperscript 2/acre and height of 5.9
ft at study end. Because competition for site resources was low, Douglas fir
seedlings developed best in this treatment. Mean Douglas fir diameter was 4.6
inches at 12 inches above mean ground line, height averaged more than 21 ft,
and mean foliar cover was 39 850 ftsuperscript 2 at
the end of the study. The cost was $227 per acre.
14. McDonald, P.M. and
G.O. Fiddler. 1999. Ecology and development of Douglas-fir seedlings and
associated plant species in a
Keywords: release treatments
manual release
chemical release
stand conditions
growth
tree morphology
economics
Abstract: On an
average site in northern coastal California, USA, a tanoak (Lithocarpus
densiflorus)-mixed shrub community was given several
treatments (manual release one, two, and three times; a combination chainsaw
and cut surface chemical treatment; two foliar chemicals; and a tank mix of the
two chemicals) to study its development over an 11-year period (1981-91) in
both a broadcast-burned (untreated control) and released (treated) condition.
The chemicals were 2,4-D, Garlon [triclopyr]
3A, and Garlon 4, each applied two times. The site
had been planted with 2+0 seedlings of Douglas fir (Pseudotsuga
menziesii) in 1979. In addition to Douglas-fir , data
are presented individually for the four most abundant and well distributed
species (tanoak, hairy manzanita (Arctostaphylos
columbiana), huckleberries (Vaccinium
ovatum and V. parviflorum),
and rhododendron (Rhododendron macrophyllum)), and
for these plus two more of the tallest and most abundant (but poorly
distributed) species (snowbush (Ceanothus velutinus), elderberry (Sambucus mexicana)) combined. In 1991, combined shrubs in the
control had a mean density of 4733 plants per acre, foliar cover of 16 800 ft2
per acre, and height of 9.5 feet. In contrast, combined shrubs in one of the
most effective treatments for controlling them (2,4-D) had a mean density of
2000 plant per acre, foliar cover of 2600 ft2 per acre and height of 5.5 feet
at the end of the study. Here, mean Douglas-fir diameter was 4.0 inches at 12
inches above mean ground line, height averaged 18.7 feet, and mean foliar cover
was 34 800 ft2 per acre. The cost (including chemical) was $77 per acre. The
biological and economical data in this paper provide the ecosystem manager,
wildlife biologist, and fuels manager with knowledge on how to attain plant
communities with different density and development potentials, and the cost of
creating them.
15. McDonald, P.M., G.O.
Fiddler and H.R. Harrison. 1995. Mulching to regenerate a harsh site: effect on
Douglas-fir seedlings, forbs, grasses, and ferns.
Pacific-Southwest-Research-Station, USDA-Forest-Service Research-Paper
PSW-RP-222. ii + 10 p.
Keywords: release treatments
manual release
growth
Abstract: Douglas
fir (Pseudotsuga menziesii)
seedlings, 2+0, were planted in February 1989 on pastureland in the Arcata
District, central coastal
16. McDonald, P.M. and
O.T. Helgerson. 1990. Mulches aid in regenerating
Keywords: release treatments
manual release
growth
Abstract: A discussion
of the effects of various types of mulches for controlling seedling environment
in plantations, mostly of Pseudotsuga menziesii and Pinus ponderosa.
17. Pabst, R.J., J.C. Tappeiner, II and M. Newton. 1990. Varying densities of
Pacific madrone in a young stand in
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
18. Prasad, R. 2000. Some
aspects of the impact and management of the exotic weed, Scotch broom (Cytisus scoparius (L.) Link) in
Keywords: release treatments
manual release
growth
photosynthesis
Abstract: A
recent cutover area near
19. 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
20. Tung, C.H., J. Batdorff and D.R. DeYoe. 1986a.
Survival and growth of Douglas-fir seedlings with spot-spraying, mulching and
root-dipping. Western-Journal-of-Applied-Forestry 1(4): 108-111.
Keywords: nursery operations
release treatments
chemical release
manual release
tree/stand health
growth
Abstract: In
trials near
21. Wagner, R.G. and M.W.
Rogozynski. 1994. Controlling sprout clumps of bigleaf maple with herbicides and manual cutting. Western
Journal of Applied Forestry 9(4):118-124.
Keywords: release treatments
chemical release
manual release
stand conditions
Abstract: Trials
were conducted in 5 young Douglas fir (Pseudotsuga menziesii) plantations for controlling bigleaf
maple (Acer macrophyllum) clumps. Herbicides tested
were glyphosate (Roundup), imazapyr
(Arsenal), metsulfuron methyl (Escort), triclopyr amine (Garlon 3A), triclopyr ester (Garlon 4), and
2,4-DP [dichlorprop] + 2,4-D (Weedone
170). Four methods of herbicide application (basal spray, thinline,
foliage spray, and cut-surface) and 3 treatment timings (early foliar, late
foliar, and dormant periods) were tested. Manual cutting alone was also
evaluated at each of the treatment timings. Imazapyr foliage
sprays, triclopyr ester thinline,
dormant 3% triclopyr ester basal spray, late-foliar
2,4-DP + 2,4-D basal spray, and manual cutting with triclopyr
amine cut-surface application provided the best control among the treatments
tested over the 3 yr of study. Imazapyr foliage
sprays provided the best long-term control by killing most treated clumps. Triclopyr ester thinline
treatments provided the most consistent and effective results among the basal
applications. Stump applications of triclopyr amine were
more effective than manual cutting alone or manual cutting with glyphosate cut-surface application.
22. 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
23. Woods, J.H., D. Kolotelo and A.D. Yanchuk. 1995.
Early selection of coastal Douglas-fir in a farm-field test environment. Silvae-Genetica 44(4): 178-186.
Keywords: genetic tree improvement
planting operations
site preparation
mechanical preparation
release treatments
chemical release
manual release
genetic relationships
wood quality
growth
Abstract:
Farm-field tests are progeny tests established using intensive site
preparation, close spacing and nearly complete weed control. Early growth and
wood density of coastal Douglas-fir (Pseudotsuga menziesii) in a farm-field environment for up to 7 years
from seed were compared with stem volume and wood density from 11 field sites
at age 13 (20-25 of commercial rotation). The farm-field test material
comprised 70 full-sib families from six 6-tree half-diallels
(some reciprocals and missing crosses) without selfs.
Parent trees were from natural stand selections in the coastal area of