1. 1997. PNWTIRC Annual Report 1996-97,
Keywords: genetic tree improvement
tree/stand protection
tree phenology
growth
wood quality
tree physiology
Abstract: The
report describes highlights for 1996-97, current research (3 projects), student
project updates (3 projects), planned Douglas fir [Pseudotsuga
menziesii] seed orchards for the new millennium and
other planned activities of the PNWTIRC, a research cooperative operating in
the Pacific Northwest area of North America (USA and Canada). Details are
included of publications and finances. Details of the 3 current research
projects and the 3 student projects, which all concern Douglas fir, are
presented as short papers including brief results: (1) Influence of second
flushing on cold hardiness; (2) Seedling drought physiology study; and (3)
Quantitative trait loci influencing cold hardiness; (4) Seedling cold
hardiness; (5) Growth response of saplings to drought; and (6) Measurement
study follow-up: age-age correlations in forking defects.
2. Abdel-Gadir,
A.Y. and R.L. Krahmer. 1993. Genetic variation in the
age of demarcation between juvenile and mature wood in Douglas-fir.
Wood-and-Fiber-Science 25(4): 384-394.
Keywords: genetic tree improvement
wood quality
Abstract:
Variation in the age of demarcation between juvenile and mature wood based on
wood density was studied in 180 Douglas fir (Pseudotsuga
menziesii) trees. Ring density profiles were
generated from X-ray densitometry of increment cores from each of 3 randomly
selected trees from each of 30 wind-pollinated families (parent trees) grown in
2 replication blocks in
OSU Link
Non-OSU
Link
3. Abdel-Gadir,
A.Y., R.L. Krahmer and M.D. McKimmy.
1993. Relationships between intra-ring variables in mature Douglas-fir trees
from provenance plantations. Wood-and-Fiber-Science 25(2): 182-191.
Keywords: genetic tree improvement
wood quality
genetic relationships
Abstract:
Relationships among a variety of densitometric
characteristics of juvenile and mature wood from 360 trees growing in two
plantations of Douglas fir (Pseudotsuga menziesii) in
4. Arnott,
J.T. and F.T. Pendl. 1994. Field performance of
several tree species and stock types planted in montane
forests of coastal
Keywords: nursery operations
planting operations
growth
tree/stand health
wood quality
Abstract: Planting
trials were established at sites within the Mountain Hemlock and montane Coastal Western Hemlock biogeoclimatic
zones. Six test areas were chosen within each zone. Amabilis
fir (Abies amabilis), noble
fir (A. procera), yellow cedar (Chamaecyparis
nootkatensis) and mountain hemlock (Tsuga mertensiana) were the
species selected for planting in the Mountain Hemlock zone. In addition to Abies amabilis and A. procera, western white pine (Pinus
monticola), western redcedar
(Thuja plicata), Douglas
fir (Pseudotsuga menziesii)
and western hemlock (Tsuga heterophylla)
were planted in the Coastal Western Hemlock zone. Plug (PSB 211), plug transplant and bareroot
stock types were used for the eight species across both zones. Seedlings were
planted during the autumn (September/October) and spring (May) in each of two
successive years: 1978-79 and 1979-80. Survival, growth and tree form 13 years
after planting were used as indicators of the reliability (a combination of
tree survival and form) and productivity of the planting treatment
combinations. Noble fir and amabilis fir were the
most reliable species in the Mountain Hemlock zone; i.e. these species have
average survival rates higher than 80% and few form defects. Yellow cedar
crowns were badly broken by snow, which reduced the reliability of this species
in the early years of plantation establishment. The growth, survival and form
of mountain hemlock ranked between that of the true firs and yellow cedar.
Noble fir was by far the most productive species in the Mountain Hemlock zone.
Within the Coastal Western Hemlock zone no single species demonstrated a
superior combination of productivity or reliability. Douglas fir, western
hemlock and western redcedar were good species in the
lower elevations of the zone, whereas noble fir and amabilis
fir were better species at the upper elevational
limits of the zone. Western white pines should be avoided until rust-resistant
seed sources are available. Little variation was found among the three planting
stock options and even less between the two planting seasons. Plug transplant
stock was more reliable than bareroot or plug stock;
productivity ranked from greatest to least in the following order within both
zones: plug transplant, bareroot and plug stock. This
ranking among stock types may well change as different stock types are
developed. However, the relative size and design differences among stock types,
no matter when they become available, will always have an effect on the
ultimate reliability and productivity of planted trees. Autumn planting gave
significantly lower survival in the Coastal Western Hemlock zone only.
5.
Keywords: genetic tree improvement
yield
wood quality
economics
Abstract: Relationships
between tree traits and tree value for lumber production were investigated. For
the purposes of estimating relative economic weights for use in multitrait selection in coastal Douglas fir (Pseudotsuga menziesii var. menziesii), tree height, diameter at breast height, and
branch diameter were measured on 164 trees (ages 36-66 yr) sampled from 11
intensively managed stands with a wide range of site attributes, growing
conditions, ages and stocking histories in western Washington and Oregon.
Increment cores from a subsample (92) of these trees
were assayed by X-ray densitometry to determine wood density. Bole volume was
derived by summing the log volumes of all logs from each tree. Value of lumber
recovered from each tree was determined in a separate mill study using both
visual and machine stress rated (MSR) grading rules. Multiple linear regression was used to relate tree value to the growth and
wood quality traits. Stem volume and branch diameter significantly influenced
tree value under visual grading, with relative economic weights of 0.06 dmsuperscript 3 and -5.22 cm, respectively. Wood density
significantly influenced tree value under MSR grading (relative economic
weights: 0.06 dmsuperscript 3, -6.69 cm, and 0.06 kg/msuperscript 3, respectively), where lumber strength is
measured more accurately. These regression coefficients can be used directly as
economic weights in selection indices in the development of advanced breeding programmes for Douglas fir.
6. Barbour, R.J.,
Keywords: thinning
yield
wood quality
Abstract:
Hundreds of thousands of hectares of Douglas fir (Pseudotsuga
menziesii) plantations in coastal forests in the US
Pacific Northwest have been established over the past 40 years. Density
management regimes designed to increase structural and compositional diversity
in these plantations are being tested and implemented on an operational scale,
in order to satisfy goals of ecosystem management. These regimes are designed
to promote various tree and stand characteristics,
such as trees with large limbs, stands with multi-layered canopies, and dense unthinned patches. Changes in forest management policy
associated with these types of regimes raise questions about whether it is
possible to manage for both ecosystem values and timber production.
State-of-the-art growth models were used to simulate stand development and wood
product yields under several silvicultural
prescriptions. The results indicated that timing and intensity of early thinnings are critical in determining both stand structure
and wood quality. It is concluded that it should be possible to manage Douglas
fir plantations to provide a high degree of structural diversity, and wood
products with a quality similar to that grown in many industrial plantations.
7. Barbour, R.J. and D.L. Parry.
2001. Log and lumber grades as indicators of wood quality in 20- to
100-year-old Douglas-fir trees from thinned and unthinned
stands. Pacific-Northwest-Research-Station,-USDA-
Keywords: thinning
commercial thinning
wood quality
Abstract: This
report examines the differences in wood characteristics found in coastal
8. Bodner, J. 1984. Effect of thinning and
fertilization on wood properties and intra-ring characteristics in young
Douglas-fir. Holzforschung-und-Holzverwertung
36(1): 5-11.
Keywords: fertilization
thinning
wood quality
Abstract: Studies
were made on samples from a total of 21 trees (felled in 1982) from 42-yr-old
control and thinned/[N] fertilizer-treated stands near
9. Briggs, D.G., F. Mecifi and W.R. Smith. 1986. Effect of sludge on wood
properties: a conceptual review with results from a sixty-year-old Douglas-fir
stand. In The forest alternative for treatment and utilization of municipal
and industrial wastes. Ed. D.W. Cole, C.L. Henry,
and W.L. Nutter.
Keywords: fertilization
wood quality
Abstract:
Expected changes in wood properties due to cultural practices are reviewed. The
hormone theory and published studies on the effects of thinnings
and fertilizers are used to provide a basis for hypotheses describing the
effects of sludge treatments on wood properties. Notes are given on the effect
of municipal sludge on relative density, tracheid
characteristics and strength properties of Douglas fir.
10. Brix, H. 1993. Fertilization and thinning effect on a
Douglas-fir ecosystem at
Keywords: fertilization
thinning
growth
tree morphology
tree/stand health
carbon allocation
wood quality
tree physiology
photosynthesis
economics
Abstract:
Treatments were initiated in 1970-71 in a 24-year-old Douglas fir (Pseudotsuga menziesii) near Shawnigan Lake, Vancouver Island, British Columbia, to
determine the effects of 3 intensities of thinning (removing none, one-third
and two-thirds of basal area) and 3 levels of urea fertilizer (0, 224 and 448
kg N/ha) on the growth and biology of the trees. Subsidiary experiments were
established during 1972-87 to examine the effects of high doses of urea
(672-1344 kg N/ha), ammonium nitrate as an N source instead of urea, understorey response to thinning and fertilizer, and
responses to P and S fertilizer.
11. Busing, R.T. and S.L. Garman.
2002. Promoting old-growth characteristics and long-term wood production in
Douglas-fir forests. Forest-Ecology-and-Management 160(1/3): 161-175.
Keywords: thinning
yield
wood quality
Abstract: Trade-offs
among wood production, wood quality and ecological characteristics in the
management of harvested forest stands are explored through model simulation of
various silvicultural regimes. Long-term production
of merchantable wood, production of various types of high-quality wood, and the
level of certain quantitative ecological indicators are projected for
coniferous forests of Pacific Northwestern USA. The set of ecological
indicators used is based on the species composition and physical structure of
old, unlogged forest stands. Simulations are
performed with an ecological model of forest stand dynamics that tracks the
fate of live and dead trees. Short rotations (<50 years) produce the least
amount of high-quality wood over the multi-century simulation period. They also
fail to generate ecological attributes resembling those of old forest stands.
Production of high-quality wood is moderate to high under all rotations of 80
years or more; however, most ecological indicators require longer rotations
unless alternatives to clear felling are applied. Alternatives examined include
retention of 15% cover of live tree canopy at each harvest in combination with
artificial thinning between harvests. Thinning from below can expedite the
development of large live and dead trees, and canopy height diversity without
greatly diminishing wood quantity or quality. Proportional thinning retains understorey stems, thereby expediting the recruitment of
shade-tolerant trees. A possible drawback to thinning, particularly
proportional thinning, is the diminished production of
clean-bole wood at rotations of 150 and 260 years. It is concluded that most
wood quantity, wood quality and ecological objectives can be met with long
rotations (approximately 260 years). Certain objectives can be met with shorter
rotations (80-150 years) when treatments of thinning and canopy tree retention
are applied.
12. Cahill, J.M., T.A. Snellgrove and T.D. Fahey. 1988. Lumber and veneer recovery
from pruned Douglas-fir. Forest-Products-Journal 38(9): 27-32.
Keywords: pruning
yield
wood quality
Abstract: Logs
were selected from a 75-yr-old stand of Douglas fir (Pseudotsuga
menziesii) in
13. Carter, R.E., I.M. Miller and K. Klinka. 1986. Relationships between growth form and stand
density in immature Douglas-fir. Forestry-Chronicle 62(5): 440-445.
Keywords: planting operations
wood
quality
tree
morphology
growth
Abstract: Spacing
was found to affect stem and crown characteristics and branching at whorls 6-10
in 27-yr-old Douglas fir established at 3 spacings
(1.8x1.8, 3.6x3.6 and 4.6x4.6 m) near
14. Cole, D.W., M.L. Rinehart, D.G.
Briggs, C.L. Henry and F. Mecifi. 1984. Response of
Douglas fir to sludge application: volume growth and specific gravity. In
Proceedings of the Technical Association of the Pulp and Paper Industry 1984
Research and Development Conference, Appleton, Wisconsin, September 30-October
3. pp. 77-84.
Keywords: fertilization
thinning
growth
wood quality
Abstract: In 1977
and 1980 municipal sludge was applied to a 60-yr-old lowland Douglas fir stand
in
15. Collier, R.L. and E.C. Turnblom. 2001. Epicormic
branching on pruned coastal Douglas-fir. Western-Journal-of-Applied-Forestry 16(2):
80-86.
Keywords: pruning
thinning
wood quality
tree morphology
Abstract: The
Stand Management Cooperative (SMC 1998) at the University of Washington, USA,
conducted live crown reduction experiments in the Pacific Northwest regions of
the USA, to better understand the dynamics of the response of coastal Douglas
fir (Pseudotsuga menziesii)
to pruning. A detailed report on how frequently epicormic
branches occur, where they occur on the bole, whether or not their occurrence
is related to stand density or the amount of crown removed, and how epicormic sprouting may affect log grade, is presented. The
experiments include fifty-six 0.08 ha pruning plot in 18 installations in
16. Fight, R.D., J.M. Cahill, T.D.
Fahey and T.A. Snellgrove. 1987a. Financial
analysis of pruning coast Douglas-fir. Pacific-Northwest-Research-Station,-USDA-
Keywords: pruning
fertilization
economics
wood quality
yield
computer modeling
Abstract: Unpruned stands of Douglas fir (Pseudotsuga
menziesii) will yield little clear material under
current management regimes in western
17. Fight, R.D., J.T. Chmelik and E.A. Coulter. 2001. Analysts guide: TreeVal for Windows, Version 2.0. Pacific-Northwest-Research-Station,-USDA-
Keywords: pruning
economics
wood quality
yield
Abstract: TreeVal for Windows
provides financial information and analysis to support silvicultural
decisions in coast Douglas-fir (Pseudotsuga menziesii). It integrates the effect of growth and yield,
management costs, harvesting costs, product and mill type, manufacturing costs,
product prices, and product grade premiums. Output files from the ORGANON
growth and yield simulator can be read directly into TreeVal.
All management actions, including pruning, are supported. Results, including
product recovery information, net value, and financial analysis of silvicultural regimes, are available in both tabular and
graphical forms to facilitate comparison of alternative regimes and sensitivity
analysis with prices, costs, and other assumptions.
18. Fight, R.D.,
Keywords: pruning
planting operations
wood quality
economics
Abstract: Once
site and genetic stock are selected, management of stocking, rotation age, and
pruning are the principal means available to foresters to affect wood quality
and value in stands of coast Douglas fir (Pseudotsuga
menziesii var. menziesii) in
the
19. Gartner, B.L., J.J. Morrell, C.M.
Freitag and R. Spicer. 1999. Heartwood decay
resistance by vertical and radial position in Douglas-fir trees from a young
stand. Canadian-Journal-of-Forest-Research 29(12): 1993-1996.
Keywords: fertilization
thinning
wood quality
Abstract:
Heartwood durability of Douglas-fir (Pseudotsuga menziesii var. menziesii) was
studied as a function of vertical and radial position in boles of trees with a
wide range of leaf area/sapwood area ratios. Six 34-year-old trees were
harvested from each of three plots: very dense, thinned, and thinned and
fertilized with N, P, K, Ca, S and Fe (51, 11, 10, 7, 4 and 0.3 kg/ha,
respectively), established 14 years before at a site in the central Cascades of
Oregon. Heartwood samples from three radial positions and five heights were
incubated with the decay fungus Postia placenta [Oligoporus placenta]. There were no significant differences
in wood mass loss (decay resistance) by vertical or radial position. One could
expect that trees with high leaf area/sapwood area could have the carbon to
produce heartwood that is more resistant to decay than trees with lower leaf
area/sapwood area. However, no relationship was found between leaf area above
node 20, sapwood area there, or their ratio, and the decay resistance of outer
heartwood at that node. These results suggest that, for young Douglas-fir
trees, heartwood durability does not vary with position in the bole or with
environments that alter the balance of sapwood and leaf area in a tree. It is
suggested that young stands may thus be robust with respect to the effect of silvicultural regimes on heartwood durability.
20. Gartner, B.L., E.M. North, G.R.
Johnson and R. Singleton. 2002. Effects of live crown on vertical patterns of
wood density and growth in Douglas-fir. Canadian-Journal-of-Forest-Research
32(3): 439-447.
Keywords: thinning
pruning
wood quality
Abstract: It
would be valuable economically to know what are the biological triggers for
formation of mature wood (currently of high value) and (or) what maintains
production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production
of the two types of wood. Foresters commonly assume the bole of softwoods
produces juvenile wood within the crown and mature wood below. We tested that
assumption by comparing growth ring areas and widths and wood density
components of the outer three growth rings in disks sampled from different
vertical positions of 34-year-old Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) trees. The 18 trees were sampled from one site and
had a wide range of heights to live crown. Most of the variance (63-93%) in
wood characteristics (growth ring area: total, earlywood,
latewood; growth ring width: total, earlywood,
latewood; latewood proportion: by area, width; and ring density: total, earlywood, latewood) was due to within-tree differences
(related to age of the disk). Stepwise regression analysis gave us equations to
estimate wood characteristics, after which we analysed
the residuals with a linear model that included whether a disk was within or
below the crown (defined as the lowest node on the stem with less than three
live branches). After adjusting for tree and disk position, only 2-10% of the
residual variation was associated with whether the disk was in or out of the
live crown. There were no statistically significant differences at p=0.05
between a given disk (by node number) in versus out of the crown for any of the
factors studied. Moreover, the wood density characteristics were not
statistically significant at p=0.30. This research suggests that there was no
effect of the crown position on the transition from juvenile to mature wood as
judged by wood density. Therefore, we found no evidence to support the concept
that tree spacing and live-branch pruning have a significant effect on the
cambial age of transition from juvenile to mature wood in Douglas-fir trees of
this age.
21. Gonzalez, J.S. and J. Richards.
1988. Early selection for wood density in young coastal Douglas-fir trees.
Canadian-Journal-of-Forest-Research 18(9): 1182-1185.
Keywords: genetic tree improvement
wood quality
Abstract: Selection
age for wood density in vigorous coastal Douglas-fir (Pseudotsuga
menziesii) on Vancouver Island was determined by
examining the strength of the correlation between total-stem wood density of
50-yr-old trees and the b.h. density when the trees
were 5-30 yr old (b.h. age), and the efficiency in
terms of gain per year of tree improvement effort by selecting at ages 5-30,
relative to selecting at age 50. The linear regression and rank correlation
between total-stem and b.h. densities improved as age
increased from 5 to 15 yr, but showed no significant improvement from 15 to 30
yr. Densities of early-growth rings fluctuated considerably and their exclusion
from the calculation of b.h. density enhanced the
linear regression with total-stem density. Efficiency estimates in terms of
gain per year showed an opt. value at age 15, but the estimates for ages 10-14
were nearly as efficient.
22. Grotta,
A.T., B.L. Gartner and S.R. Radosevich. 2004.
Influence of species proportion and timing of establishment on stem quality in
mixed red alder-Douglas-fir plantations. Canadian-Journal-of-Forest-Research
34(4): 863-873.
Keywords: planting operations
tree morphology
wood quality
Abstract: The
relationships among stand structure, Douglas-fir (Pseudotsuga
menziesii) branch characteristics, and red alder (Alnus rubra) stem form attributes
were explored for 10- to 15-year-old trees growing in mixed Douglas-fir-red
alder plantations in Oregon, USA. Treatments included a range of species
proportions, and red alder was either planted simultaneously with Douglas-fir
or after 5 years. Both replacement effects (total stand density held constant)
and additive effects (stand density doubled) of competition were considered.
When the two species were planted simultaneously and red alder proportion was
low, red alder trees had low crown bases and much stem defect (lean, sweep, and
multiple stems). Douglas-fir grew slowly when the two species were planted
simultaneously. When red alder planting was delayed, species proportion did not
affect red alder stem form, and height to the base of the Douglas-fir live
crown decreased with increasing red alder proportion. Doubling Douglas-fir
density increased the height to the base of the Douglas-fir live crown;
however, doubling stand density by adding red alder did not affect Douglas-fir
crown height. Douglas-fir lumber coming from mixed stands may be inferior
because of the changes in knot characteristics associated with these different
patterns of crown recession. In stands with a low proportion of red alder, red
alder product recovery may be compromised because of the stem defects described
above.
23. Hong, S. and J.J. Morrell. 1997. Treatability of Douglas-fir heartwood with ACZA or CCA:
effect on site, silvicultural practice, and wood
properties. Forest-Products-Journal 47(10): 51-55.
Keywords: planting operations
fertilization
thinning
wood quality
Abstract: The
effects of site, silvicultural treatments, and wood
properties on treatability of Douglas-fir (Pseudotsuga menziesii) heartwood,
from
24. Jozsa,
Keywords: fertilization
thinning
wood quality
growth
Abstract: The
effect of thinning and N fertilization on growth and wood density of coastal
Douglas fir (Pseudotsuga menziesii)
on a poor site on
25. Jozsa,
Keywords: planting operations
wood quality
tree morphology
Abstract: Wood
quality is defined as the suitability of wood for a particular end-use. Wood
anatomy and tree growth are discussed in terms of macroscopic and microscopic
features of a tree examined in cross section. End-use requirements are
described in terms of lumber grading. The following wood quality attributes are
introduced, defined and discussed in terms of their practical implications for
wood processing and wood products: wood density, density variation, juvenile wood/mature wood distribution, proportion of
heartwood/sapwood, fibre length, fibril angle,
compression wood, knots, grain and extractives. The potential for influencing
tree growth characteristics (e.g. wood density, branch size) and wood quality
(structural and appearance lumber grades) through stand stocking control is
discussed.
26. Kennedy, R.W. 1995. Coniferous
wood quality in the future: concerns and strategies. Wood Science and
Technology 29: 321-338.
Keywords: planting operations
wood quality
Abstract: As the
raw material base for forest products manufacturing shifts from old-growth to
short-rotation plantation stock, the wood from these younger trees will contain
larger proportions of juvenile wood. This in turn will influence the quality of
forest products obtained. The pattern of specific gravity variation in these
trees, which varies among the five most important
27. Koshy,
M.P. and D.T. Lester. 1994. Genetic variation of wood shrinkage in a progeny test
of coastal Douglas-fir. Canadian-Journal-of-Forest-Research 24(8): 1734-1740.
Keywords: genetic tree improvement
wood quality
genetic relationships
Abstract: Directional
(longitudinal, tangential and radial) and volumetric wood shrinkage were analysed in 413 trees belonging to 48 full-sib families (4
paternal and 12 maternal parents) from an 18-year-old coastal Douglas fir (Pseudotsuga menziesii var. menziesii) progeny test in British Columbia. Six samples
per ring position (ring positions 1-5 from pith along stem radii), with two
rings in each ring position, were examined in a bolt taken at breast height
from the tree. Genetic effects were minimal for shrinkage, except for
longitudinal shrinkage at ring positions 1 and 2. High variability was expressed
among trees within plots and among samples with trees. The lack of
statistically significant family variance eliminates the possibility of
improving the shrinkage traits by genetic means, except for longitudinal
shrinkage in the first few rings. However, the high amount of variability
expressed between trees within plots and between samples within trees warrants
special attention for achieving uniformity of wood. Much of this variability
can be reduced by silvicultural methods.
28. Koshy,
M.P. and D.T. Lester. 1997. Wood shrinkage and tree growth in coastal
Douglas-fir: implications of selection. Canadian-Journal-of-Forest-Research
27(1): 135-138.
Keywords: genetic tree improvement
wood quality
growth
genetic relationships
Abstract: Phenotypic
and genetic correlations of height and diameter at breast height with wood
shrinkage were studied in an 18-year-old Douglas fir (Pseudotsuga
menziesii) progeny trial in
29. Kramer, H. and J.H.G. Smith.
1985. Establishment of Douglas fir stands in
Keywords: planting operations
thinning
pruning
growth
yield
economics
wood quality
Abstract: Square
spacing trials were established NW of Haney (180 m alt.) at 0.91, 1.83, 2.74,
3.66 and 4.57 m. Growth to age 25 yr, and simulation estimates up to 100 yr are
reported. Results indicated that extra costs (incurred by thinning) of stands
closer than 4 m spacing are difficult to justify in economic terms, because the
market for Douglas fir timber grown in British Columbia is such that only
production of large timber is economically viable. The quality of timber from
trees grown at wide spacing without thinning is acceptable in relation to
Canadian requirements, and could be improved if wide spacing were combined with
pruning. It is recommended that close spacings be
used only if availability of land is limited or demand for biomass is very
strong.
30. 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
31. Maguire, D.A., J.A. Kershaw, Jr.
and D.W. Hann. 1991. Predicting the effects of silvicultural regime on branch size and crown wood core in
Douglas-fir. Forest-Science 37(5): 1409-1428.
Keywords: thinning
precommercial thinning
commercial thinning
wood quality
Abstract: Three
major determinants of wood quality (whorl frequency, branch size and crown wood
core) in Douglas fir (Pseudotsuga menziesii)
were estimated from the dynamics of crown structure in ORGANON, an
individual-tree, distance-independent growth model. Data for the model were
collected from Douglas fir plots in
32. O'-Hara, K.L. 1991. A biological
justification for pruning in coastal Douglas-fir stands.
Western-Journal-of-Applied-Forestry 6(3): 59-63.
Keywords: pruning
growth
wood quality
Abstract: A
summary, based on a review of the literature, is presented of pruning studies
undertaken in Douglas fir (Pseudotsuga menziesii) plantations in the
33. Petruncio, M., D. Briggs and R.J. Barbour. 1997. Predicting pruned
branch stub occlusion in young, coastal Douglas-fir.
Canadian-Journal-of-Forest-Research 27(7): 1074-1082.
Keywords: pruning
tree/stand protection
tree/stand health
wood quality
Abstract: This study
examined occlusion of 335 pruned branches from 38 coastal Douglas fir (Pseudotsuga menziesii) trees
sampled from 13 stands (5 in
34. Reeb, D. 1985. Influence of spacing and artificial pruning on
the production of clearwood of Douglas-fir.
Forestry-Abstracts 46(10): 640.
Keywords: planting operations
pruning
wood quality
35. Regan, R.P. and W.M. Probesting. 1989. Development of Douglas-fir clones for
Christmas trees. In Combined Proceedings: International Plant
Propagators' Society (Vol 38): 187-191.
Keywords: genetic tree improvement
growth
wood quality
Abstract: Douglas
fir (Pseudotsuga menziesii
var. menziesii) clones have been selected for vigour and ornamental quality in Christmas tree production
in
36. Schermann,
N., W.T. Adams, S.N. Aitken and J.C. Bastien. 1997. Genetic parameters of stem form traits in a
9-year-old coastal Douglas-fir progeny test in
Keywords: genetic tree improvement
growth
wood quality
genetic relationships
tree phenology
Abstract: The
genetic control of stem form traits was investigated in a 9-year-old progeny
test comparing 80 open-pollinated families of Pseudotsuga
menziesii, located in a fertile Pacific coast site in