Whitebark pine (Pinus albicaulis) is an important, high-elevation tree species that provides critical habitat for wildlife and supplies valued ecosystem services. These trees currently face multiple threats, including attack by mountain pine beetles. The project team, including Polly C. Buotte and Jeffrey A. Hicke (University of Idaho), Haiganoush K. Preisler (US Forest Service), and Kenneth F. Raffa (University of Wisconsin), aimed to increase the understanding of the causes of the recent mountain pine beetle outbreak, and to estimate future outbreak potential given future climate change. As Polly will discuss in this webinar, researchers developed generalized additive models of the probability of tree mortality from mountain pine beetles, and then applied the best model to future climate projections. The team determined the presence of whitebark pine mortality from mountain pine beetles using USDA Forest Service aerial surveys.
Researchers found that the probability of tree mortality increased with increasing winter minimum temperature, increasing average fall temperature, and decreasing summer precipitation. Across all climate models, scenarios, and time periods, the average odds of whitebark pine mortality were greater in the future than in 1950-2006, and similar to or greater than the odds of mortality during the recent outbreak. These results suggest the potential for severe future mountain pine beetle outbreaks, given there are suitable whitebark pine trees present. Join the webinar to learn more about the findings from this project!