Mountain pine beetle and Spruce beetle are two of the most important insect pests in Wyoming's forests. Since the early 1990s, these native beetles have caused tree mortality over millions of acres of federal, state, and private forests in Wyoming. Currently, western spruce budworm is Wyoming's most concerning forest health issue. 

Emerald ash borer (EAB) is a non-native invasive insect that infests native North American ash trees. It was accidentally introduced to the Midwest and has since been spreading to other areas of the U.S. and Canada.

Satellite infestations of EAB include Boulder County, Colorado. Ash trees are native to parts of eastern Wyoming, but considering the widespread urban planting of ash trees, EAB has the potential to impact most Wyoming communities eventually. By not transporting firewood, we can substantially delay EAB's arrival in Wyoming. EAB has not yet been detected in Wyoming and there is a state EAB response plan in place.

Wyoming's biggest forest health threats include:

• • Forest structure

    • • Lack of forest age class diversity

      • Too much dead wood

  • Fire

    • • Altered fire return intervals

      • Four biggest fire seasons within last decade

      • Wildland-urban interface development

  • Logging industry

    • • Four decades of decline

      • Economically difficult to remove wood

  • Lack of water

    • • Low moisture & high temperature

      • Fire suppression & less harvesting = more trees

        • • More trees = more water needed

  • Early 2000s drought led to more tree mortality

  • Competition alone is enough to lead to beetle attack

• When combined with drought and disease, these factors can cause substantial tree mortality