Distribution of bark beetle attacks after whitebark pine restoration treatments: A case study

Whitebark pine (Pinus albicaulis Engelm.), an important component of high elevation ecosystems in the western United States and Canada, is declining due to fire exclusion, white pine blister rust (Cronartium ribicola J.C. Fisch.), and mountain pine beetle (Dendroctonus ponderosae Hopkins). This study was conducted to evaluate the effects of whitebark pine restoration treatments on the distribution of bark beetle attacks. At a site in Idaho, silvicultural treatments were implemented in summer 1998 and 1999, with prescribed burning implemented in Oct. 1999. Permanent plots (400m²) were established during summer 1999 within each treatment and monitored for 4 years. Within plots, tree characteristics were measured and a bark beetle survey was conducted. Bark beetle attacks remained low throughout the study; however, there was an increase in bark beetle attacks in 2000 after the prescribed burning. By years 3 and 4, there were virtually no successful attacks. Although bark beetles were not a serious concern at the site assessed in this study, our results indicate that managers should consider and monitor the bark beetle component of these ecosystems when implementing restoration treatments. If baseline bark beetle populations are high at the time of implementation, our results indicate that increases in beetle activity would be expected in some treatments, perhaps requiring mitigation.