Whitebark pine (Pinus albicaulis Engelm.), an important component of western high-elevation forests, has been declining in both the United States and Canada from the combined effects of the exotic disease white pine blister rust (caused by the pathogen Cronartium ribicola), mountain pine beetle (Dendroctonus ponderosae) outbreaks, altered fire regimes, and climate change. These combined threats have led to the recent listing of whitebark pine as a high priority Candidate Species under the Endangered Species Act.