Life Sciences Commons^™

Bark Beetle Activity In Douglas-Fir, Pseudotsuga Menziesii Var. Glauca Mirb. (Franco), Following The 1994 Beaver Mountain Fire, Catherine A. Cunningham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The 1994 Beaver Mountain fire ignited the canopies of subalpine fir, Abies lasiocarpa, and spread ground fire into adjacent Douglas-fir forests, Pseudotsuga menziesii var. glauca. Despite shorter flight seasons due to lower annual temperatures and persistent snow, the Douglas-fir bark beetle, Dendroctonus pseudotsugae Hopkins, attacked a range of moderately fire-injured host conifers. Logistic regression models illustrated that in 1995 associated bark beetles selected large diameter Douglas-fir with 60-80% bole char, 60-80% crown volume scorch, and 50-70% probability of mortality due to fire. In 1996 beetle preference shifted to smaller diameter trees with lighter fire injury. Tree size was …