Epidemic And Endemic Populations Of The Southern Pine Beetle

This study was conducted to evaluate the dynamics of endemic populations of mountain pine beetle (Dendroctonus ponderosae Hopkins). In addition, we extended the geographical range of an existing data base recorded in Utah with similar data from Wyoming. This work was accomplished in lodgepole pine (Pinus contorta Dougl. Var. latifolia Engelm.) stands on the Medicine Bow National Forest in south-central Wyoming. Thirty-eight variable-radius paired plots (BAF 10) were measured during the summer of 1987. Host-tree condition and mountain pine beetle infestation characteristics were determined from currently and previously infested trees. Presence and severity of Armillaria root disease and stem pathogens was determined. Tree condition and infestation patterns were similar at this site to those found in earlier studies. Trees selected by endemic mountain pine beetle populations were infested with Comandra blister rust (Cronartium Comandra PK) and root disease (Armillaria spp.). Host-tree condition and mountain pine beetle infestation patterns recorded in this study parallel those identified earlier in Utah and will help land managers identify trees to cut to reduce stand hazard to mountain pine beetle infestation.

"This book presents a synthesis of published information on mountain pine beetle (Dendroctonus ponderosae Hopkins [Coleoptera: Scolytidae]) biology and management with an emphasis on lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests of western Canada. Intended as a reference for researchers as well as forest managers, the book covers three main subject areas: mountain pine beetle biology, management, and socioeconomic concerns. The chapters on biology cover taxonomy, life history and habits, distribution, insect-host tree interactions, development and survival, epidemiology, and outbreak history. The management section covers management strategy, survey and detection, proactive and preventive management, and decision support tools. The chapters on socioeconomic aspects include an economic examination of management programs and the utilization of post-beetle salvage timber in solid wood, panelboard, pulp and paper products."--Publisher's description.

Two empirical methods for rating susceptibility of mountain pine beetle attack in ponderosa pine were evaluated. The methods were compared to stand data modeled to objectively rate each sampled stand for susceptibly to bark-beetle attack. Data on bark-beetle attacks, from a survey of 45 sites throughout the Colorado Plateau, were modeled using logistic regression to estimate the probability of attack on individual trees from tree and stand variables. The logistic model allowed flexibility to easily scale results up to a stand level for comparison to the empirical methods. The empirical method, developed by Munson and Anhold, most closely correlated to the logistic regression results. However, the Munson/Anhold method rated all 45 study sites as either moderately or highly susceptible to bark-beetle attack, which raises concern about its lack of sensitivity. Future work on evaluating risk of bark-beetle impact should consider more than stand characteristics.