Alison Scoville (Biological Sciences)
Whitebark pine (Pinus albicaulis) plays a vital role in colonizing newly disturbed area, providing shade for other tree species to colonize, and supplying food for a variety of birds and mammals, such as Clark’s nutcrackers (Nucifraga columbiana) and grizzly bears (Ursus arctos horribilis). Whitebark pine’s decline has been attributed to several factors such as white pine blister rust (Cronartium ribicola), mountain pine beetle (Dendroctonus ponderosae) outbreaks, and fire exclusion. In 2009, the U.S Forest Service began to install permanent plots in whitebark pine stands in Washington and Oregon as part of a Pacific Northwest restoration strategy to track blister rust and mountain pine beetle mortality. Forest Service crews conducted surveys on these plots that included standard tree inventory and measurements of blister rust, mountain pine beetle, and fire activity. Before summer 2020, only 12 of 47 plots located in the Okanogan-Wenatchee National Forest had been remeasured. To evaluate the changes that occurred in the whitebark population and provide updated data to the Forest Service, volunteer crews during summer 2020 remeasured eight of these plots located in three areas of the Okanogan-Wenatchee National Forest: Mission Ridge, Clover Springs, and Darland Mountain. Results indicate a significant increase in blister rust stem cankers (from 2% to 16%: t(5) =-5.6434, P = .0024) and low, unchanged mountain pine beetle activity, but more plot remeasurements are needed to understand the current status of the whitebark pine population, the changes that occurred since 2009, and the future status of whitebark pine.
Keywords: Whitebark pine, Monitoring, Conservation