Vast Oregon wildfire lab helping foresters prepare for hotter planet
SILVER LAKE, Oregon — When a monster of a wildfire whipped into the Sycan Marsh Preserve here in south-central Oregon in July, Katie Sauerbrey feared the worst.
Sauerbrey, a fire manager for The Nature Conservancy, the conservation group that owns the 30,000-acre preserve, was in charge of a crew helping to fight the blaze — the Bootleg fire, one of the largest in a summer of extreme heat and dryness in the West — and protect a research station on the property.
Watching the fire, which had already rapidly burned through thousands of acres of adjacent national forest, she saw a shocking sight: Flames 200 feet high were coming over a nearby ridge. “I said, OK, there’s nothing we can do,” she recalled.
But as the fire got closer, it changed dramatically, Sauerbrey said. “It had gone from the most extreme fire behavior I had ever seen in my career to seeing 4-foot flame lengths moving through the stand.” While the fire kept burning through the forest, its lower intensity spared many trees, and the station survived.
Firefighters describe this kind of change in behavior as a fire “dropping down,” shifting from one with intense flames that spread quickly from tree crown to tree crown to a lower-level burn that is less dangerous. There are various reasons this can happen, including localized changes in winds, moisture, tree types and topography.
But for Sauerbrey and her colleagues with The Nature Conservancy, what she witnessed was most likely a real-life example of what they and others have been studying for years: how thinning of trees in overgrown forests, combined with prescribed, or controlled, burns of accumulated dead vegetation on the forest floor, can help achieve the goal of reducing the intensity of wildfires by removing much of the fuel that feeds them.
It’s a goal shared by others in the West, where the 2021 fire season saw several extremely large fires. The Bootleg fire, which burned more than 400,000 acres, was one of the largest in the state’s history. And two fires in Northern California, the Dixie and Caldor fires, together burned 1.2 million acres.
Drought and extreme heat, made worse by global warming, play a role by making forests tinder dry and easier to burn. But many researchers say that more than a century of management policies that called for every fire to be extinguished, no matter how small, also contribute to the problem by allowing dead vegetation to accumulate and add fuel to fires.
That July day, the Bootleg fire reached a part of the preserve called the Coyote Restoration, which had been treated twice. In 2016 it was thinned, and three years later Sauerbrey, a “burn boss” certified to plan and conduct prescribed fires, had burned out the dead underbrush.
“Undoubtedly in my mind, those buildings would not be there if we hadn’t done these treatments,” she said, although the conservancy is also beginning research to better understand why the fire behaved as it did.
The organization has been studying forest treatments at Sycan Marsh for nearly two decades. The goal has been to use thinning and intentional burning to restore forests closer to conditions that existed in the past, when fire was a regular part of the forest life cycle and naturally removed some trees and dead underbrush.
“We’ve been suppressing fire in these systems for 150 to 120 years,” said James Johnston, a researcher at Oregon State University. “And when there is ignition, drought, dry weather and high winds, we have fires that burn hundreds of thousands of acres.” These fires kill most of the large trees that make up the forest canopy, which is not what happened historically, he added.
Thinning has often been criticized as a way for timber companies to harvest the biggest, most valuable trees in a forest with little regard for the ecological consequences. And prescribed burns can in rare cases be disastrous: One in New Mexico in 2000 was driven out of control by unexpected winds and eventually destroyed more than 200 homes.
But done with care, and with regard for forest ecology, researchers say, these techniques can make forests healthier and more resilient to fire.
“Our past forest management did certainly log a lot of our larger trees out,” said Sharon Hood, a research ecologist with U.S. Forest Service in Montana. But practices have changed, she said.