ASHLAND, Oregon — On a clearing overlooking Siskiyou Mountain Park in Ashland, a navy blue helicopter is making laps back and forth up the forested hillside. …In areas of this forest, anywhere from 20-80% of the fir trees are dead.” …Chris Chambers worries that a large wildfire could permanently change this forest if hotter temperatures driven by climate change make it hard for fir trees to grow back after a fire. He says this thinning work will help soften the blow. If we don’t stay ahead of it, then we might not have a forest in 20, 30, 40 years”. The work in the Ashland watershed is aimed at the symptoms of the Douglas fir die-off. But it doesn’t explain why the trees are dying. …Max Bennett is a retired Oregon State University extension forester. He’s been researching this fir tree die-off, and he co-authored a 2023 paper called “Trees on the Edge.”