The Oregon Department of Forestry and the USDA Forest Service will conduct low-level flights in June to monitor forest health. This survey, which began in the 1940s and paused only during the 2020 pandemic, is the longest continuous annual survey of its kind in the United States. Airborne researchers conduct the survey from fixed-wing aircraft, flying between 1,500 and 2,500 feet above ground level at speeds of 90 to 140 miles per hour. They follow a systematic grid pattern, four miles apart, to identify areas where trees are in distress. “Oregon has about 30 million acres of forest so flying in a grid pattern over it allows us to find problems even in remote areas hard to reach by vehicle or on foot,” said Christine Buhl, an entomologist with the Oregon Department of Forestry.