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U.S. Forest Service
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United States Department of Agriculture

Forest Health News 2021

Tree Mortality Summary of WESTERN BARK BEETLES Now Available

By Jeanine Paschke, USDA Forest Service Contractor


May 2021

Western Bark Beetle Tree Mortality Summary Map

Western Bark Beetle Tree Mortality Summary Map.

The summary of areas with tree mortality from bark beetles in the Western US from 2000 – 2020 is now available.
Insect and disease surveys for 2020 were impacted by COVID-19 and some regions and states had reduced coverage or were unable to conduct aerial surveys. In place of aerial surveys, regions and states may have used a "scan and sketch" method to derive damage areas from high resolution imagery. This method was not a full replacement for aerial surveys and in several areas, we saw a reduction in surveyed acres. This summary includes all data sources.
The findings show a 26.7 million acre footprint for mountain pine beetle and a 59.2 million acre footprint for all western bark beetles over the past 21 years. Many areas of pest activity overlap from year to year. The footprint areas are the cumulative area covered by pest activity with no double counting of acres between years. In total, 25 species of bark beetles were included in the calculation. Complexes, insect/disease and other multi damage phenomena that contain a bark beetle component like five-needle pine decline, subalpine fir mortality, true fir pest complex, and pinyon pine mortality are also included.

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Summary of areas with tree mortality from bark beetles in the Western US from 2000 – 2020