Sustain Our Nation's Forests and Grasslands

Alaska impacted by most recent spruce beetle outbreak

ALASKA — An ongoing spruce beetle outbreak, beginning in 2016, has impacted roughly 910,000 acres in Alaska. Impacted spruce trees can easily be seen while driving along Southcentral highways, reaching as far north as Denali State Park. Spruce beetles are native to Alaska forests and outbreaks of varying size and intensity are known to have occurred throughout history.

Spruce beetle damage was recorded during the 2018 forest health aerial detection annual survey. The outbreak is located primarily in the Matanuska-Susitna River drainages and adjacent watersheds (500,000 acres) and the northwestern Kenai Peninsula (48,000 acres). Additionally, spruce beetle activity was observed this year in the northern portions of the Municipality of Anchorage (1,500 ac) as well as scattered, small pockets of activity within the remainder of the municipality and along the Glenn Highway north of the Anchorage bowl. Information collected during surveys may not necessarily depict the entirety of the outbreak. 

Landowners are encouraged to inspect their trees for signs of beetle attack and consider removing infested trees this winter if possible. Trees appearing healthy now may still have been attacked. Needles do not change color until the second year following beetle attack. Spruce beetles initially attack the base and trunk of spruce trees leaving behind red boring dust. Trees attacked this summer will likely die over the next year. 

State and federal forest health professionals work together to provide resources to Alaskans to minimize impacts from the outbreak. Workshops are being developed for the public on how to mitigate spruce beetle impacts. Recommendations and information on spruce beetle biology and mitigation are available at

Spruce beetle mortality recorded during aerial survey in the Matanuska-Susitna Valley. Photo courtesy of Forest Service/Forest Health Protection Staff.

Spruce beetle (Dendroctonus rufipennis). Photo courtesy of Forest Service/Forest Health Protection Staff.