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

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The regression methods used in this study provided a more sensitive measure of form changes
than previous methods, were independent of size distribution, and facilitated extrapolations and
evaluation of temporal trands.
616. Thomson, A.J., K.D. Tudor, V.J. Korelus and D.R. Ralph. 1988. Detecting the response of
Douglas-fir to nitrogen fertilization by regression of periodic annual basal area increment against
basal area. Canadian-Journal-of-Forest-Research 18(10): 1343-1346.
Keywords: fertilization
growth
Abstract: Douglas-fir (Pseudotsuga menziesii) b.a. response to urea application at 112 and
224 kg N/ha was studied on a medium site on Vancouver Island, British Columbia. Regression of
tree periodic annual b.a. increment against b.a. was used to estimate within-plot growth rates.
Higher growth rates were observed in the plots treated with fertilizer. The slope coefficients of
the regressions were used to investigate spatial and temporal variation in growth rates.
617. Thomson, T.A. 1989. Evaluating some financial uncertainties of tree improvement using the
capital asset pricing model and dominance analysis. Canadian-Journal-of-Forest-Research 19(11):
1380-1388.
Keywords: genetic tree improvement
economics
Abstract: Although uncertainty considerations are of prime importance in capital
budgeting, forestry investments are often evaluated without comparing their uncertainty level
with their rates of return. An examination was made of some financial uncertainties of a Douglas
fir (Pseudotsuga menziesii) tree improvement programme in the US Pacific Northwest with
analysis of likely rates of return on investment. Biophysical uncertainties such as amount of
genetic gain or uncertainty of site quality were determined by a priori assumption to be nonmarket;
thus, use of expected value adjusted for these risks. The market uncertainties of tree
improvement were found to be reasonable in relation to other investments, as sensitivity analysis
showed that the financial risks were small or the measured beta (covariance of the assets' returns
with the market's returns divided by the variance of the market) was low. It is concluded that the
tree improvement investment is worthwhile, considering its risk as well as return.
618. Trappe, J.M. 1983. Effects of the herbicides bifenox, DCPA, and napropamide on mycorrhiza
development of ponderosa pine and Douglas fir seedlings in six western nurseries. Forest-Science
29(3): 464-468.
Keywords: nursery operations
mycorrhizal response
Abstract: The herbicides were each applied (for weed control) at 2 rates to beds of
seedlings in nurseries in California, Oregon and Washington. Seedlings were lifted 7-8 months
after sowing and the roots examined for mycorrhizae. No herbicide treatment significantly
reduced the proportion of feeder roots colonized or the number of mycorrhizal types, compared
with controls. Ponderosa pine seedlings treated with DCPA [chlorthal-dimethyl] had a
significantly greater proportion of mycorrhizal feeder roots than those treated with the other
herbicides (but n.s.d. from controls), and a significantly greater mean number of mycorrhizal
types than controls or the napropamide treatment. Douglas fir seedlings treated with napropamide