1. 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
2. Chen, J.M. and T.A. Black. 1992.
Foliage area and architecture of plant canopies from sunfleck
size distributions. Agricultural-and-Forest-Meteorology 60(3/4): 249-266.
Keywords: thinning
pruning
tree morphology
Abstract: A
Poisson model is developed to describe sunfleck or
gap size distributions beneath clumped plant canopies. This model is based on
the assumption that foliage clumps are randomly distributed in space and
foliage elements are randomly distributed within each clump. Using this model,
the foliage clumping index, leaf area index (L), clump area index, element area
index in each clump, and element and clump widths were successfully derived for
two artificial canopies and a thinned and pruned Douglas-fir (Pseudotsuga menziesii) forest
stand. It is shown that existing theories for deriving L from measurements of
canopy gap fraction have limitations, and use of canopy architectural
information derived from canopy gap size distribution can substantially improve
the technique for indirectly measuring L of plant canopies.
3. 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
4. Fight, R.D., N.A. Bolon and J.M. Cahill. 1993. Financial analysis of pruning
Douglas-fir and ponderosa pine in the
Keywords: pruning
economics
computer modeling
Abstract: Recent lumber
recovery studies of pruned and unpruned Douglas fir (Pseudotsuga menziesii var. menziesii) and ponderosa pine (Pinus
ponderosa var. ponderosa) were incorporated into computer software using lumber
grade prices, growth and yield data, the cost of pruning, and interest rates to
determine the expected financial return from pruning. Financial analyses showed
that the cost of pruning at which the investment would yield an expected 4%
real rate of return was positive on sites where individual tree growth is
fairly high, pruning is done as early as biologically possible given
limitations on crown removal, and the harvest is 30 to 70 yr after pruning. The
better situations in Douglas fir showed a break-even cost of up to $21/tree and
an internal rate of return exceeding 9%. The better situations in ponderosa
pine showed a break-even cost of up to $11/tree and an internal rate of return
of 7%.
5. Fight, R.D., J.M. Cahill and T.D.
Fahey. 1992. DFPRUNE users guide. Pacific-Northwest-Research-Station,-USDA-
Keywords: pruning
economics
computer modeling
Abstract: The
DFPRUNE spreadsheet program is designed to estimate the expected financial return
from pruning coast Douglas fir (Pseudotsuga menziesii var. menziesii). It is
a significant revision of the PRUNE-SIM program. The PRUNE-SIM program was
based on the average product recovery for unpruned
logs from a single stand that received frequent light thinnings.
The DFPRUNE program incorporates new recovery information for unpruned young-growth Douglas fir and can be used to assess
the economic potential of pruning for a wide range of management regimes.
Product prices and descriptions of trees at time of pruning and at time of
harvest must be supplied by the user. The DFPRUNE program was developed for the
Lotus
6. 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
7. Fight, R.D., J.M. Cahill, T.D.
Fahey and T.A. Snellgrove. 1988. A new look at
pruning coast Douglas-fir. Western-Journal-of-Applied-Forestry 3(2): 46-48.
Keywords: pruning
thinning
fertilization
economics
Abstract: A short
account of an evaluation of the financial returns of pruning coast Douglas fir
(Pseudotsuga menziesii),
using new product-recovery information and computer software, and assuming
that: the analysis is for lumber, interest rates are 4 and 8%, stands are
fertilized 2 or 3 times and thinned periodically, and that trees were pruned at
age 20 yr. Results showed that higher returns from pruning could be achieved by
concentrating pruning in younger stands that have a higher site index and that
will be fertilized.
8. Fight, R.D., J.M. Cahill, T.A. Snellgrove and T.D. Fahey. 1987b. PRUNE-SIM users guide. Pacific-Northwest-Research-Station,-USDA-
Keywords: pruning
economics
computer modeling
Abstract: PRUNE-SIM
is a spreadsheet template (program) that allows users to simulate a financial
analysis of pruning coast Douglas fir (Pseudotsuga menziesii var. menziesii) in the
9. 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.
10. 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
11. 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.
12. Hermann, R.K. and D.P. Lavender.
1999. Douglas-fir planted forests. New-Forests 17(1/3): 53-70.
Keywords: genetic tree improvement
nursery operations
planting operations
site preparation
release treatments
fertilization
thinning
pruning
tree/stand protection
growth
yield
Abstract: A
combination of superior wood quality and high productivity has made Douglas fir
(Pseudotsuga menziesii) one
of the premier timber trees in the world. As such, it is grown as a plantation
species in several countries in Europe and South America, and in
13. Kimball, B.A., D.L. Nolte, D.L.
Griffin, S.M. Dutton and
Keywords: pruning
tree/stand protection
growth
tree physiology
tree/stand health
Abstract: The impact
of live canopy pruning (removal of all live and dead whorls between the ground
and 5 m height, resulting in removal of ~40% of the live canopy) on the
carbohydrate and terpene content of vascular tissue
was investigated in the lower bole of Douglas fir (Pseudotsuga
menziesii) on 4 sites in NW Oregon. Cambial zone
vascular tissue samples were collected from pruned and unpruned
trees in the lower bole and within the live canopy. Current year's radial
growth was estimated from the mass of vascular tissue removed from the 800 cmsuperscript 2 area sampled from each tree. Chemical
analyses were conducted to determine the concentration of carbohydrates and terpenes in the samples. Results indicated that 2 yr
following treatment, pruning resulted in reduced growth and decreased
carbohydrate content of the vascular tissue. Pruning had no effect on the terpene concentration of the vascular tissue. The impact of
pruning on the foraging selection of black bears (Ursus
americanus) was evaluated by surveying bear damaged
trees in a 50 acre stand of pruned and unpruned
timber. Odds ratios indicate that black bears were 4 times more likely to
forage unpruned than pruned Douglas fir. Tree
selection may be explained in part by the higher availability of carbohydrates
in the unpruned tree with respect to the pruned tree.
14. 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.
15. 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
16. Omule, S.A.Y., D.E. Paul and L.M. Darling. 1994. Cost of pruning
Douglas-fir in coastal
Keywords: pruning
economics
Abstract: Artificial
pruning can increase the quantity of high-value clear lumber harvested from Douglas
fir (Pseudotsuga menziesii),
but the pruning cost per tree is relatively high. To prune a young Douglas fir
to 6 metres in one lift and two lifts took,
respectively, 9.5 and 10.1 minutes in 14- and 18-year old stands with average
spacing between trees of about 3 metres on flat or
0-30% south-facing slopes in coastal British Columbia. The associated costs
were $2.09 and $2.22. This included minor travel time between trees, but
excluded the cost of travelling to the site,
selecting and marking trees to be pruned, and purchasing and maintaining the
pruning equipment. Differences in pruning time between one-lift pruning and
two-lift pruning, in one or two passes, were small. A D-handled saw was
preferred to the more strenuous snap-cut pruner with
ratchet-style pinions, based on observations on a pruning time-study of 5
operators.
17. 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
18. Potts, S.J., B.R. Hartsough, S.E. Reutebuch and
J.L. Fridley. 1997. Manual polesaw pruning of
Douglas-fir. Applied-Engineering-in-Agriculture 13(3): 399-405.
Keywords: pruning
economics
Abstract: A
time-and-motion study was conducted in
19. 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
20. Reukema, D.L. and J.H.G. Smith. 1987. Development over 25 years of
Douglas-fir, western hemlock, and western redcedar
planted at various spacings on a very good site in
Keywords: planting operations
pruning
growth
yield
tree morphology
Abstract: Five spacing
trials were established during 1957-67 at the University of
British Columbia Research Forest, covering a range of spacings
from 1 to 5 m and of experimental designs (49-tree-plot, 0.2-ha plot,
rectangularity, Nelder and variable block trials).
Results showed that initial spacing is among the most important factors
influencing stem and crown development, and stand growth and yield for Douglas
fir (Pseudotsuga menziesii),
western hemlock (Tsuga heterophylla)
and western redcedar (Thuja
plicata). Top heights were initially taller at closer
spacings, but are now similar at all spacings. Av. ht. is now shorter at close spacing.
Decreases in heights to dead and live crowns and increases in diam. of lower stem, taper and crown size occurred as
spacing increased. B.a. and
stand vol. increased as spacing decreased until onset of density-related
mortality. It is concluded that initial wide spacings
with rectangularities up to 2:1 (e.g. 6x3 m) will
result in efficient production of large trees of high value and satisfactory
quality. Pruning of widely spaced trees to enhance lower stem quality is
strongly recommended.
21. Rosso, P. and E. Hansen. 1998. Tree vigour
and the susceptibility of Douglas fir to Armillaria
root disease. European-Journal-of-Forest-Pathology 28(1): 43-52.
Keywords: fertilization
thinning
pruning
tree/stand protection
growth
tree/stand health
carbon allocation
Abstract: The
effects of thinning, fertilization and pruning on the vigour
of Douglas fir (Pseudotsuga menziesii)
and its susceptibility to Armillaria root disease
were investigated in
22.
Keywords: fertilization
thinning
pruning
tree/stand protection
growth
yield
tree/stand health
Abstract: The
Warm Springs Indian Reservation,
Non-OSU
Link
23. Turnblom, E.C. and R.L. Collier. 2003. Growth of residual branches
on pruned coastal Douglas-fir. Western-Journal-of-Applied-Forestry 18(3):
185-188.
Keywords: pruning
wood quality
Abstract: Anecdotal
evidence gathered from pruning crew observations indicates that there may be
enhanced branch growth at the new crown base in young pruned coastal
Douglas-fir (Pseudotsuga menziesii
var. menziesii) trees compared to unpruned
trees. This has the potential to reduce the quality and value of the stem above
the pruned portion of the bole. An analysis of the size of branches in the
remaining crown on pruned trees and matched unpruned
trees of the same size at the time of pruning indicates that residual branches
do not increase in diameter or length in response to light and moderate
pruning. However, with a severe pruning there was a modest increase in branch
length. Residual branch size in response to pruning 4 years after treatment
appears to offer no real risk in degrading quality of the unpruned
portion of the stem as a cost for increasing the quality of the pruned stem.
24. Velazquez-Martinez, A., D.A.
Perry and T.E. Bell. 1992. Response of aboveground biomass increment, growth
efficiency, and foliar nutrients to thinning, fertilization, and pruning in
young Douglas-fir plantations in the central Oregon Cascades.
Canadian-Journal-of-Forest-Research 22(9): 1278-1289.
Keywords: fertilization
thinning
pruning
growth
carbon allocation
tree physiology
tree morphology
Abstract: The
effect of thinning and silvicultural practices (multinutrient fertilization and/or pruning) on total
aboveground biomass increment and growth efficiency was studied over three
consecutive 2-year periods (1981-1987) in young Douglas fir (Pseudotsuga menziesii)
plantations in the central Oregon Cascades. Plantations were 21-27 yr old in
1987. Plots were heavily thinned (leaving 300 trees/ha), moderately thinned
(leaving 604 trees/ha) or left unthinned (leaving
3459 trees/ha) in 1981. Fertilizer (N, P, K, Ca, S and Fe) was applied with
slow-release tabs. Net above-ground biomass annual increment over the 6-year
period averaged 14.5, 7.8, and 5.5 t/ha for the high-, medium-, and low-density
plots, respectively. Growth efficiency, after dropping sharply between leaf
area indexes (LAI) of 1 and 6 msuperscript
2/msuperscript 2, remained relatively constant up to the highest measured LAI
of 17. Consequently, above-ground biomass increment continued to increase at LAIs well above that at which the Beer-Lambert law predicts
maximum light should be absorbed. Foliage analyses indicated that thinning
improved N, K and Mg nutrition and increased the translocation of K from
1-yr-old foliage to support new growth. However, fertilizer application
increased foliar N and P contents only when coupled with pruning, suggesting
that trees favour total leaf area over individual needle
nutrition. Indications of K and Mg limitations in this study are supported by
other recent studies of Douglas fir.