Lewis County Foothills Among Thousands of Forest Acres Were Destroyed by Heat, Insects and Disease Last Year, DNR Says

Trees: Foothills of Lewis County Among Areas Hardest Hit, According to State


About 555,000 acres of forests in Washington were damaged by last year’s intense summer heat, foliar diseases and beetles, according to the Department of Natural Resources (DNR).

DNR surveyed approximately 19 million acres of land in the state and released the report of their 2021 findings on Tuesday. The U.S. Forest Service (USFS) helped the agency conduct the aerial survey, which is done every year.

“This comprehensive accounting makes clear the impacts our worsening climate crisis have on our forests and the urgency of our efforts to combat our forest health crisis in Washington,” Public Lands Commissioner Hilary Franz said in a news release Tuesday.

Western Washington was the most affected by the heat from last summer, according to the report. The western side of the Olympic Peninsula, western Pacific County, Wahkiakum County, southern Clark and Skamania counties, and the foothills of Snohomish, King and Lewis counties were the areas most impacted, with nearly 84,000 acres of damage.

The number could still be higher “because crown discoloration was difficult to see by observers looking to the west and south,” the report noted.

Those trees were affected by “desiccation damage,” which is what happens when they lose moisture before turning brown and eventually dying.

Beetles caused their fair share of damage to Washington forests last year too, the report adds.

Although damage from pine bark beetles still claimed 95,000 acres of forest, DNR’s report said that number is lower than it was in 2015. Douglas fir beetles claimed 51,700 acres last year, but that number has been decreasing as well.

The western pine beetle damaged 37,800 acres in 2021 and the report said those numbers have been steadily increasing since 2012.

Additionally, a “possibly non-native” sooty bark disease that affects maples, horse chestnuts, Pacific dogwoods and cherry plums has now been found in areas such as Olympia, Bellingham and the Seattle area. More surveys are planned this summer to detect the fungus known as Cryptostroma corticale in other areas, as the agency notes in the report that they are unsure where else it may be.

DNR also added that the pathogen Phytophthora ramorum is still being “found in streams associated with commercial plant nursery trade activity.” The pathogen can potentially cause Sudden Oak Death, a forest disease that kills not only oak trees but Douglas fir and redwoods as well.

In the news release, DNR and USFS said that forest management promotes “robust and resilient forests,” and that “thinning, selective harvests, prescribed fire and removing underbrush are critical forest management tools that advance forest health — especially as the state faces increasingly hotter, drier summers.”