Predicting Postfire Douglas-Fir Beetle Attacks and Tree Mortality in the Northern Rocky Mountains

Authors

Sharon Hood
Barbara Bentz

Document Type

Article

Journal/Book Title/Conference

Canadian Jorunal of Forest Research

Publication Date

2007

Issue

6

Volume

37

First Page

1058

Last Page

1069

Abstract

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were monitored for 4 years following three wildfires. Logistic regression analyses were used to develop models predicting the probability of attack by Douglas-fir beetle (Dendroctonus pseudotugae Hopkins, 1905) and the probability of Douglas-fir mortality within 4 year following fire. Percent crown volume scorched (crown scorch), cambium injury, diameter at breast height (DBH), and stand density index for Douglas-fir were most important for predicting Douglas-fir beetle attacks. A nonlinear relationship between crown scorch and cambium injury was observed, suggesting that beetles did not preferentially attack trees with both maximum crown scorch and cambium injury, 1 and 2 years following fire. Crown scorch, cambium injury, DBH, and presence/absence of beetle attack were the most important variables for predicting postfire Douglas-fir mortality. As DBH increased, the predicted probability of mortality decreased for unattacked trees but increased for attacked trees. Field sampling suggested that ocular estimated of bark char may not be a reliable predictor of cambium injury. Our results emphasize the important role of Douglas-fir beetle in tree mortality patterns following fire, and the models offer improved prediction of Douglas-fir mortality for use in areas with or without Douglas-fir beetle populations.

Comments

Originally published by the National Research Council - Canada. Publisher's PDF and HTML fulltext available through remote link. View and Print this Publication at: http://www.fs.fed.us/rm/pubs_other/rmrs_2007_hood_s001.pdf

Recommended Citation

Hood, S. and Bentz, B. (2007). Predicting postfire Douglas-fir beetle attacks and tree mortality in the northern Rocky Mountains. Can. J. For. Res. 37(6): 1058–1069.