IntensIve sIlvIculture - Forest Science Labs - Research Network ...
IntensIve sIlvIculture - Forest Science Labs - Research Network ...
IntensIve sIlvIculture - Forest Science Labs - Research Network ...
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164<br />
growth<br />
Abstract: The Douglas-fir tussock moth (Orgyia pseudotsugata) is one of the most<br />
destructive forest defoliators of Douglas fir (Pseudotsuga menziesii), grand fir (Abies grandis)<br />
and white fir (A. concolor) in western North America. An outline is given of current pestmanagement<br />
programmes used in Oregon, which emphasize the annual monitoring of insects in<br />
forests with outbreak histories to determine early changes in population numbers and to predict<br />
trends. When outbreaks develop, several environmentally safe chemical and microbial<br />
insecticides are effective in reducing larval numbers and preventing serious defoliation. Computer<br />
models predicting growth loss, tree mortality, and top-kill during outbreaks are available as aids<br />
to making management decisions. Silvicultural practices favouring seral nonhost species on highrisk<br />
sites may be the best prescription for reducing the effect of tussock moth outbreaks.<br />
371. Massicotte, H.B., L.E. Tackaberry, E.R. Ingham and W.G. Thies. 1998. Ectomycorrhizae<br />
establishment on Douglas-fir seedlings following chloropicrin treatment to control laminated-root<br />
rot disease: assessment 4 and 5 years after outplanting. Applied-Soil-Ecology 10(1/2): 117-125.<br />
Keywords: tree/stand protection<br />
mycorrhizal response<br />
Abstract: Laminated-root rot, caused by Phellinus weirii, is a serious disease affecting<br />
Douglas fir [Pseudotsuga menziesii] and other commercially important species of conifers in<br />
northwestern North America. The effect of chloropicrin (used to control Phellinus weirii) on<br />
nontarget organisms, including ectomycorrhizae, is uncertain. A study was carried out to examine<br />
ectomycorrhizal development on Douglas firs after the application of chloropicrin. The study was<br />
carried out in Matlock, Washington, USA, 4.5 and 5.5 years following chloropicrin application.<br />
In areas around stumps treated with 20% and 100% of the labelled dosage and in areas around<br />
non-treated stumps, chloropicrin did not adversely affect the formation of ectomycorrhizae on<br />
young Douglas fir seedlings by naturally occurring fungi. No significant effect on the abundance<br />
or type of mycorrhizas were detected. In this study chloropicrin did not affect these mycorrhizal<br />
associations, for at least 5 years following application.<br />
372. Maze, J., S. Banerjee and Y.A. El-Kassaby. 1989. Variation in growth rate within and among<br />
full-sib families of Douglas-fir (Pseudotsuga menziesii). Canadian-Journal-of-Botany 67(1): 140-<br />
145.<br />
Keywords: genetic tree improvement<br />
growth<br />
Abstract: Variation in growth rate in the 4 uppermost lateral branches of 2-yr-old seedlings<br />
in a common garden was greatest among individuals within full-sib families. Results are<br />
consistent with those from other studies on conifers which indicated that there is more within than<br />
between intraspecific group variation. Growth rate was greatest in seedlings produced by crossing<br />
trees with the highest av. increment (ht. and diam.) and least in seedlings produced by crossing<br />
trees with the lowest av. increment. Seedlings with the lowest growth rate, however, were similar<br />
to those produced by crosses between other trees with high av. increment. This implies that<br />
phenotypically superior parents, as assessed in a natural stand, do not necessarily produce<br />
superior offspring in the second year of growth. Results are discussed in relation to evolutionary<br />
theory.
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