After destroying millions of trees in the Midwest and East Coast, the emerald ash borer appears poised to cross the Columbia River
Long game: Emerald ash borer beetles can kill an ash tree within three years of initial infestation. Photo: NPS
By Ian Rose. October 9, 2025. In summer 2022, forest managers in Oregon got the news they’d been dreading for years. Emerald ash borers, an invasive wood-boring beetle from Asia responsible for the death and decline of tens of millions of ash trees in North America, had been found in Forest Grove, just west of Portland.
This year, on Sept. 10, the Oregon Department of Forestry confirmed that the destructive insects had arrived in Portland…