Drought and insects have killed an unprecedented number of Oregon’s Douglas fir trees during the last decade, costing billions in timber value, damaging infrastructure and ramping up wildfire danger. Beginning in 2015 and accelerating with the 2021 heat dome, roughly 635,000 acres of forest have been impacted by what’s known as Douglas fir “dieback” in southwest Oregon and the Willamette Valley. “It’s hitting trees of all sizes, but it’s hitting larger and older trees the hardest,” Max Bennett, a retired forest researcher with Oregon State University, told members of the Oregon Legislature on Sept. 30. “What we’re seeing now is unprecedented.” The dieback has led to $1.1 billion in lost timber value, $500 million in potential road hazard costs and created a tinderbox of forest fuel capable of spawning the West’s most destructive wildfires, a group of foresters and researchers told the House Committee on Agriculture, Land Use, Natural Resources and Water.