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method is presented and illustrated with two examples. The method involves a simple decision
analytic structure. Projections were made for pure coastal Douglas fir Pseudotsuga menziesii for
several treatments using three previously published growth models. Present Net Worth (PNW)
was used as the criterion for choosing the treatment option and rotation age. The first example
involved an initial planting density decision. Three planting densities were considered, viz. (1)
2500, (2) 1100 or (3) 750 seedlings/ha. The second example involved the decision to thin a 15-yrold
stand to a spacing similar to that produced by (1). The options were: (a) no treatment; (b) thin
to 1100 stems/ha; and (c) thin to 500 stems/ha. The best strategy depended on which growth
model was used. The study showed that a simplified decision analytic approach is a useful
method to evaluate a decision, when aided by several growth models.
368. Marshall, P.L. 1989. The economic value of additional information about treatment-response
information for coastal Douglas-fir. Forest-Economics-and-Policy-Analysis-Research-Unit,-
University-of-British-Columbia Working-Paper 121. 39 p.
Keywords: planting operations
thinning
precommercial thinning
economics
growth
Abstract: A simple decision analytic approach was applied to initial planting density and
precommercial spacing decisions for coastal Douglas fir (Pseudotsuga menziesii) across a range
of sites in British Columbia. The range of biological response was represented by the output from
3 growth and yield models. Recent production costs and product values were applied to obtain
value per hectare after delivery of logs to the mill. Future costs and revenues were discounted at
4, 6 and 8%. The best decisions from each growth model are presented by scenario. Limitations
of the analysis and managerial implications are discussed.
369. Marshall, V.G. and H.J. Barclay. 1994. Response of young Douglas-fir to urea fertilizer applied
on and off snow. Forestry-Chronicle 70(3): 294-298.
Keywords: fertilization
growth
Abstract: The effects of 200 kg N ha-1 applied as urea fertilizer on 50 cm of snow or on
bare ground were studied in an 11-year-old Douglas fir (Pseudotsuga menziesii) plantation on
Vancouver Island. Core samples were taken from all trees on the plot 6 yr after treatment; height
was measured for 20 selected dominant trees per plot 3 months and 4 yr after treatment. Up to 2
years following treatment, urea significantly increased absolute DBH increments over controls in
all trees and the 20 selected trees per plot; response to fertilizer application on snow was equal to
that on bare ground. Between the 3rd and 9th year following treatment, mean DBH increments
were not significantly different for any treatment. Four-year absolute volume increments were 63
and 87% greater than the controls for bare-ground and on-snow applications, respectively.
370. Mason, R.R. and B.E. Wickman. 1991. Integrated pest management of the Douglas-fir tussock
moth. Forest-Ecology-and-Management 39(1-4): 119-130.
Keywords: tree/stand protection
tree/stand health
stand conditions