Document Type

Greater Yellowstone Ecosystem Report

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Forest managers in the western U.S. are currently confronted with a bark beetle epidemic that is unprecedented in extent, severity, and duration. Several species of native bark beetle including the mountain pine beetle (MPB), spruce beetle, western balsam bark beetle, and Douglas-fir beetle are simultaneously affecting over 5 million ha of forest in the Intermountain West (Logan et al. 2003, Hicke et al. 2006). Estimates of the total area affected by the current bark beetle outbreak are updated annually, typically using aerial surveillance and manual mapping techniques. However, these estimates are often inaccurate and do not provide quantitative information on stand-level beetle activity and/or tree mortality. More importantly, these annual estimates of “spread” of the epidemic do not provide any information on the abundance of the surviving understory trees, which may be substantial, nor do they provide information on post-disturbance tree seedling establishment. This “advance forest regeneration” represents the future forests in these regions. Therefore, understanding the current structure of the forests is critical for making predictions about future structure and function.