T
T
T
Understory

Bark Beetle Associations in Western Forests

Abstract

Author: Brandon McWilliams

Many native species of bark beetles affect trees across the Western United States. Most of the time, bark beetle populations remain small and only target weakened or damaged trees, but when conditions are favorable, beetle populations erupt. This fact sheet summarizes a study examining the spatial and temporal patterns of nine specific bark beetle/host tree interactions in order to better understand how specific associations behave. 

Download (PDF 1.05MB)
Download (PDF 1.05MB): https://research.fs.usda.gov/sites/default/files/2025-12/pnw-bark_beetle_association_fact_sheet_-_final_review_v2.pdf
Last updated December 17, 2025