Cooler, wetter parts of Pacific Northwest likely to see more fires, new simulations predict

Alex Dye, lead author of the study, said understanding how fire regimes might change under future climate conditions is important for developing adaptation strategies.

The results were published today. JGR Biogeosciences.

Dye, a faculty research associate in the OSU College of Forestry, and collaborators with the U.S. Forest Service developed novel, extensive wildfire simulations for more than 23 million acres of forested land west of the Cascade Range crest in Oregon and Washington. held

Projections show that for a 30-year period beginning in 2035, the North Cascades region of Washington, the Olympic Mountains, the Puget Lowlands and the western Oregon Cascades could see at least twice as much fire activity. As seen during the last 30 years. said.

To a lesser extent, the trend holds for the western Washington Cascades and Oregon Coast Range, he added.

Forests in all affected areas are the linchpins of many socio-ecological systems in the Northwest, meaning more fires will put pressure on everything from drinking water sources and timber resources to biodiversity and carbon stocks, Dye said.

“The moist, highly productive forests of the Northwest don’t have fires as often as other parts of the West, like California or eastern Oregon,” Dye said. “But fire naturally occurs in the PNW ‘Westside,’ as we call it — fire systems in this region are actually quite complex. It can be difficult to predict fire probability in an environment where there is a lot of experimentation. No information on fire history to model.”

The relative frequency of fires also means it’s easy for the general public to think of the Westside as not a high-risk area, Dye said, and it also means the region is less likely to be studied. Not the center as it has just completed. .

But recent large fires, such as the one in the Northwest around Labor Day 2020, showed what can happen when wildfires strike Westside areas.

“And what if fires like this start happening more frequently in the near future?” Dai said. “What if it becomes once every 200 years to once every 50 years, or once every 25 years when climate change brings warmer and drier conditions to the region?”

Climate is only one factor affecting wildfires, but it’s an important one, he said. He sees the findings as an important planning tool to help the Northwest prepare for the rapid pace of fires over the next few decades.

“Describing the possibilities of how, when and where climate change might affect fire systems helps bracket everyone’s expectations,” he said. “Particularly important among our findings are new insights into the potential for a shift toward more frequent and larger fires, particularly those larger than 40,000 hectares, as well as more fires burning in early fall. shifts toward when extreme weather has the potential to increase fire spread.”

Forty thousand hectares is just under 99,000 acres.

Collaborating with Dye on the study were Andy McEvoy and Rebecca Lemons of the OSU College of Forestry and Matt Riley, Karen Riley, John Kim and Becky Kerns of the Forest Service. Riley and Kim work at the Western Wildland Environmental Threat Assessment Center in Corvallis, Kerns is at the Pacific Northwest Research Station in Corvallis, and Riley is based at the Rocky Mountain Research Center in Missoula, Montana.

The research was supported by the Western Wildland Environmental Threat Assessment Center and the Pacific Northwest Research Station Westside Fire Initiative.