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179. Entry, J.A., K. Cromack, Jr., R.G. Kelsey and N.E. Martin. 1991. Response of Douglas-fir to
infection by Armillaria ostoyae after thinning or thinning plus fertilization. Phytopathology 81(6):
682-689.
Keywords: thinning
fertilization
tree/stand protection
growth
tree morphology
carbon allocation
tree/stand health
tree physiology
Abstract: Second-growth stands of Douglas-fir (Pseudotsuga menziesii) were thinned to a
5- x 5-m spacing (TT); additional plots were thinned and fertilized once with 360 kg of N (as
urea)/ha (TF). An unthinned, unfertilized stand (UT) served as a control. Ten years after
treatment, trees were inoculated with 2 isolates of A. ostoyae. Trees receiving the TF and TT
treatments produced greater diameter growth, leaf area, and wood production/msuperscript 2 leaf
area per year than did those under the UT treatment. Rates of infection by A. ostoyae were
highest in trees that received the TF and lowest in trees that received the TT treatment. Concn of
sugar, starch and cellulose in root bark tissue were highest in trees receiving the TF treatment and
lowest in trees receiving TT treatment. Concn of lignin, phenolics and protein-precipitable
tannins were highest in root bark from TT trees and lowest in root bark from TF trees.
Biochemical parameters of root bark tissue were regressed with incidence of infection;
coefficients of determination (rsuperscript 2) ranged from 0.07 (starch) to 0.57 (phenolic
compounds). Ratios of the energetic costs of phenolic and of lignin degradation to the energy
available from sugars (Epd:Eas and Eld:Eas) were correlated with incidence of infection
(rsuperscript 2 = 0.77 and 0.70, respectively). It is concluded that thinning combined with
fertilization may predispose P. menziesii trees to infection by A. ostoyae by lowering concn of
defensive compounds in root bark and increasing the energy available to the fungus to degrade
them.
180. Erickson, R.D. 1995. Douglas-fir tussock moth. In Forest-Pest-Leaflet (9):4. Pacific-Forestry-
Centre,-Canadian-Forest-Service.
Keywords: tree/stand protection
tree/stand health
Abstract: The recognition, biology, host plants, injuriousness, distribution and control of
the lymantriid Orgyia pseudotsugata, especially on Douglas fir (Pseudotsuga menziesii), in
British Columbia are discussed. Natural controls, such as parasitoids, predators and a nuclear
polyhedrosis virus, normally control endemic populations, and a list is provided of 3 species of
parasitic Diptera and 17 Hymenoptera that have been reared from the lymantriid in British
Columbia.
181. Fashler, A.M.K. and Y.A. El-Kassaby. 1987. The effect of water spray cooling treatment on
reproductive phenology in a Douglas-fir seed orchard. Silvae-Genetica 36(5-6): 245-249.
Keywords: genetic tree improvement
seed orchard management
tree/stand protection
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