A New Study Suggests Oregon’s Forests Are Already Changing Due to Wildfires and Climate Change

Many Oregonians have firsthand experience with the short-term effects of megafires. But a new Portland State University study suggests that the increase in wildfires is already creating long-term changes in Oregon's landscape, too.

After two decades of frequent wildfires, alpine forests are already adapting to become more fire resilient.

Published in September, the study examined the ecological makeup of forests in the Cascades that have seen severe, repeated wildfires.

Since the turn of the millennium, forests around Mount Adams and Mount Jefferson have been burned by large fires at intervals of less than 12 years. Historically, those high-elevation areas would see large fires only once every 50 to 200 years.

The study attributes that to the climate, which dried out normally cool, wet forests for longer stretches of the year, turning them into arid fuel for fires.

But there's at least some good news—Oregon's mountainous woods are already adapting.

The study suggests that the new forests emerging from burn zones will be less dense, pine-dominant and patchy, and thus less likely to fuel megafires.

"For forest land managers and stakeholders," the study concludes, "these adaptive trade-offs must be weighed against the benefits of seeking to maintain (e.g., by replanting) existing forest compositions, which may be poorly adapted to future climate and fire regimes in the long term."

Indigenous people used fire to shape Oregon's landscape for generations. But for the last century, the U.S. Forest Service has governed the lands observed in PSU's study with a policy of fire suppression. That's created flammable forests dense with conifers and underbrush.

While the megafires themselves certainly aren't a good thing, the way they've begun to shape forests on Mount Adams and Mount Jefferson just might be.

"Wildfire can be a great catalyst for change, but that change doesn't have to be entirely negative," said Sebastian Busby, the study's lead author, in an interview with his alma mater PSU. "We must learn to co-exist with wildfires, use them effectively, and embrace the positive elements they bring to our regional forests and ecosystems."