Canadian Forest Service Publications
Evaluation of factors affecting tree and stand susceptibility to the Douglas-fir beetle (Coleoptera: Scolytidae) 1999. Shore, T.L.; Safranyik, L.; Riel, W.G.; Ferguson, M.; Castonguay, J. The Canadian Entomologist 131: 831-839.
Issued by: Pacific Forestry Centre
Catalog ID: 5340
Availability: PDF (request by e-mail)
Tree and site characteristics were compared between 19 groups of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested by Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins and 19 uninfested groups to identify individual or combinations of characteristics associated with Douglas-fir beetle attacks. Of the tree characteristics, diameter, height, age, phloem thickness, bark thickness, and a standardized variable consisting of diameter divided by the last 10 year's growth rate (DBHTYG), showed significant differences. None of the site characteristics showed significant differences between infested and uninfested areas. Two models, identified through discriminant analysis, placed 84% and 87% of the data in the correct infestation groups. These models included the variables diameter, height, phloem thickness, aspect and DBHTYG in various combinations. These results were confirmed using a jackknifed cross-validation approach. These variables have potential for use in the development of a biological process model of tree and stand susceptibility to the Douglas-fir beetle.