IntensIve sIlvIculture - Forest Science Labs - Research Network ...

Abstract: Cone production and radial growth increment were studied for 8 years in a
Douglas fir (Pseudotsuga menziesii) seed orchard on Vancouver Island, British Columbia, in 365
trees representing 29 open-pollinated (half-sib) families. Genetic correlations for the two traits
were compared for each of the 8 years. Six of the correlations were significantly negative, while
the remaining two were significantly positive. The predominantly negative correlation between
cone production and growth indicates that selection for one of these two characters will
effectively select against the other. The practice of selecting for high cone-producing trees in seed
orchards may also be expected to yield slower-growing trees.
43. Barclay, H.J. and C.R. Layton. 1990. Growth and mortality in managed Douglas fir: relation to a
competition index. Forest-Ecology-and-Management 36(2-4): 187-204.
Keywords: fertilization
thinning
growth
tree/stand health
Abstract: Twelve-year increments of diameter at breast height (DBH), height, and volume
in thinned and fertilized 45-year-old Douglas fir (Pseudotsuga menziesii) stands on Vancouver
Island, Canada, were related (by regression) to degree of thinning, amount of fertilizer (3x3
factorial), initial DBH, and a competitive stress index (CSI). The ability of the CSI to predict
growth after treatment was examined. Causes of tree death, and CSI data, are presented, and the
relationship between them discussed. The CSI was found to be only moderately good at
predicting Douglas fir growth and mortality: initial DBH provided a better predictor. Most
mortality in unthinned plots resulted from suppression, and correlated reasonably well with CSI;
mortality in thinned plots was not correlated with CSI, and resulted principally from snow
damage. Tree height variability generally became less over the 12 years following treatment,
which is more consistent with two-sided than one-sided competition predictions, a result which is
contrasted to that of many other species.
44. Barclay, H.J., P.C. Pang and D.F.W. Pollard. 1986. Aboveground biomass distribution within
trees and stands in thinned and fertilized Douglas-fir. Canadian-Journal-of-Forest-Research 16(3):
438-442.
Keywords: fertilization
thinning
carbon allocation
Abstract: Nine years after heavy thinning and fertilization with urea, 34-yr-old Douglas firs
at Shawnigan Lake (British Columbia) were destructively sampled. Dry wt. of seven
aboveground components (wood, bark, dead branches, new or old foliage, new twigs and live
branches) were determined and regression equations from d.b.h. were developed. Differences
among treatments were shown for all biomass components and for the proportion of the total
biomass allocated to each component. Thinning reduced the proportion of wood, bark and dead
branches while increasing the proportion of foliage and live branches. Fertilization increased the
proportion of branches but had negligible effects on the proportions of other components.
45. Barclay, H.J. and J.A. Trofymow. 2000. Relationship of readings from the LI-COR canopy
analyzer to total one-sided leaf area index and stand structure in immature Douglas-fir. Forest-
Ecology-and-Management 132(2/3): 121-126.
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