PORTLAND, Ore. (AP) — Ecologists in a vast region of wetlands and forest in remote Oregon have spent the past decade thinning young trees and using planned fires to try to restore the thick stands of ponderosa to a less fire-prone state.
This week, the nation’s biggest burning wildfire provided them with an unexpected, real-world experiment. As the massive inferno half the size of Rhode Island roared into the Sycan Marsh Preserve, firefighters said the flames jumped less from treetop to treetop and instead returned to the ground, where they were easier to fight, moved more slowly and did less damage to the overall forest.
The initial assessment suggests the many years of forest treatments worked, said Pete Caligiuri, Oregon forest program director for The Nature Conservancy, which runs the research at the preserve.
“Generally speaking, what firefighters were reporting on the ground is that when the fire came into those areas that had been thinned … it had significantly less impact.”
The reports were bittersweet for researchers, who still saw nearly 20 square miles of the preserve burn, but the findings add to a growing body of research about how to make wildfires less explosive by thinning undergrowth and allowing forests to burn periodically — as they naturally would do — instead of snuffing out every flame.
The Bootleg Fire, now 606 square miles in size, has ravaged southern Oregon and is the fourth-largest fire in the state’s modern history. It’s been expanding by up to 4 miles a day, pushed by gusting winds and critically dry weather that’s turned trees and undergrowth into a tinderbox.
Fire crews have had to retreat from the flames for 10 consecutive days as fireballs jump from treetop to treetop, trees explode, embers fly ahead of the fire to start new blazes and, in some cases, the inferno’s heat creates its own weather of shifting winds and dry lightning. Monstrous clouds of smoke and ash have risen up to 6 miles into the sky and are visible for more than 100 air miles.
The fire in the Fremont- Winema National Forest merged with a smaller nearby blaze Tuesday, and it has repeatedly breached a perimeter of treeless dirt and fire retardant meant to stop its advance.
More evacuations were ordered Monday night, and a red flag weather warning signifying dangerous fire conditions was in effect through Tuesday. The fire is 30 percent contained.
“We’re in this for as long as it takes to safely confine this monster,” Incident Commander Rob Allen said Tuesday.
At least 2,000 homes have been evacuated at some point during the fire and another 5,000 threatened. At least 70 homes and more than 100 outbuildings have gone up in flames. Thick smoke chokes the area where residents and wildlife alike have already been dealing with months of drought and extreme heat. No one has died.
The Bootleg Fire was one of many fires burning in a dozen states, most of them in the West. Sixteen large uncontained fires burned in Oregon and Washington state alone on Monday.
Historically, wildfires in Oregon and elsewhere in the U.S. West burned an area as big or bigger than the current blaze more frequently but much less explosively.