PORTLAND, Ore. (KOIN) — Climate change, droughts, invasive insects and other factors have had an impact on Oregon’s vast forests for years, but recent research reveals a proliferating issue.

Environmental journalism nonprofit Columbia Insight first reported on the data collection effort from the Oregon Department of Forestry and the U.S. Forest Service, which found that 1.1 million acres with fir trees in Oregon had died off in 2022 alone.

“This survey is actually one of the longest running in the nation of its kind,” Christine Buhl, Forest Entomologist at ODF, told KOIN 6 News on Tuesday. “It’s a forest health survey that we fly over the entire state of Oregon that’s forested to collect data on insects, diseases, abiotic stressors that are damaging or killing trees.”

According to Buhl, forest health is almost always impacted by several, complex factors, rather than one singular cause.

“The primary thing we think of damaging these trees is climate change that is causing ongoing hot drought,” she said. “And it’s not only that it’s really hot and really dry, but either long duration droughts — they’re happening frequently — and the timing of them is very important as well. Early in the season when trees are waking up and need a lot of moisture, it’s really dry out there.”

The entomologist listed other primary causes such as root diseases that break down trees’ root systems, and the invasive Balsam Woolly Adelgid insect that continues to stress trees. After the trees are already hindered by these primary agents, secondary agents like the fir engraver beetle can cause the trees to die-off.

These factors have been reported by entomologists for a long time, but ODF hasn’t seen fir tree mortality of this magnitude since the agency was founded in 1911.

“In our history of collecting data, I believe that we have not detected 1 million acres of true fir mortality ever,” Buhl said. “However, we have had peaks in mortality across the landscape in Oregon of combined tree species from multiple agents that have been comparable to some of our worst wildfire seasons.”

USFS and ODF’s latest Forest Health Highlights in Oregon review did say that the heat dome of 2021 was novel, and could have lasting effects on the state’s forests. It may be too late to reverse those effects, but Buhl says strategies like thinning defective trees or planting tree species in their preferred habitat could help.

“On the other hand, there’s not a lot we can do on the larger scale with climate change. We’re reaching the point where there’s not really much we can do to turn back and we just need to try and slow the progress of climate change,” Buhl said.