Summer is still more than a month and a half away, but enormous wildfires have already consumed landscapes and darkened skies in Arizona, New Mexico and Nebraska. Whipping winds threw flames across the terrain around Boulder, Colo., in December and March.
In Boulder, worries about wildfire used to be focused around August and late summer, when lightning strikes can ignite the timbers. “Now the focus is every month,” said John Potter, a deputy director at the city’s Open Space and Mountain Parks department.
As deadly wildfires become a terrifying fixture of life for many Americans, more of the country is embracing an ancient tool to limit the devastation: careful, controlled burns that clear away vegetation and help prevent wildfires from exploding into catastrophes. But in many places, the changing climate is making intentional burns much more complicated to carry out.
The United States Forest Service used prescribed fire across a record 1.8 million acres of federal land last year, and the agency is aiming to treat an additional 50 million acres with fire and mechanical brush thinning over the coming decade. President Biden’s infrastructure law puts $5 billion toward reducing combustible flora and combating wildfires in other ways. California, Oregon and other states are exploring legal changes to encourage more burning.
With human-caused global warming heating up and drying out large parts of the country, however, wildfire seasons are growing longer, narrowing the windows for performing controlled fires safely. Shifting patterns of rain and wind are adding to the complications for burners. In many states, efforts to treat more land with fire are also running up against bureaucratic hurdles and funding and personnel shortages.
So far this spring, exceptionally dry and windy conditions have prevented Boulder’s mountain parks department from carrying out any major burns, Mr. Potter said. That raises plenty of concern about how bad wildfires could get this summer.
“Fingers crossed,” he said.
Even in humid Florida, changing conditions are forcing land managers to get creative about when they burn, said J. Morgan Varner, the director of fire research at Tall Timbers Research Station and Land Conservancy in Tallahassee. Heavy rains derailed plans in March, which is usually prime season for burning in the state. “We’re dealing with a really dynamic climate that makes planning difficult,” Dr. Varner said.
For much of the past century, America’s approach to fires was to put out any and all of them. A series of devastating blazes in 1910 hardened the government’s belief that fire was the enemy. Indigenous land-management practices were cast aside as pseudoscience; intentional burning was regarded as the behavior of woods arsonists and miscreants.
But the ferocious infernos of recent years have called attention to the need for a better way. Scientists now believe the long focus on fire suppression left the nation’s forests overcrowded and overgrown — one reason today’s wildfires are so destructive.
Between 2005 and 2019, major blazes in the West and the Great Plains burned nearly four times as much total area each year, and took place nearly twice as often, compared with the last two decades of the 20th century, one recent study found. Since 1979, nearly every part of the globe where wildfires are a problem has experienced more extreme heat and dryness, other recent research has shown.
In California, the winter rainy season is getting shorter but more intense, scientists say. This gives grass and brush more time to dry out and turn flammable in the fall, while still providing them ample water to grow the following spring — a double whammy for wildfire risk.
“I don’t think people realize that we’re actually at a point where, some of these fires, we cannot put them out,” said Lenya N. Quinn-Davidson, a fire adviser with the University of California Cooperative Extension and director of the Northern California Prescribed Fire Council. “We really need to be thinking in different ways about how we do things.”
Changes are afoot in some states. California passed a law last year letting land managers off the hook for firefighting costs in the unlikely event that a properly planned prescribed fire goes awry. Oregon is looking to do something similar. The California legislature is considering creating a $20 million fund that would compensate homeowners for losses caused by prescribed burns.
Oregon in 2019 changed its air quality rules to allow more prescribed fires to take place near towns and communities. Mr. Potter said Boulder’s mountain parks department was exploring whether it needed to work with Colorado officials to re-examine air quality strictures. The trade-off, of course, might be more smoke choking residents’ lungs.
“There’s still sometimes that lack of understanding that a little smoke right now can save us from a whole lot of smoke later on,” said Jessica E. Halofsky, director of the Forest Service’s Northwest Climate Hub in Olympia, Wash.
Only a tiny share of prescribed fires get out of control and cause injuries or damage to homes. But when they do, they can leave long-lasting distrust.
In Bastrop County, Texas, heavy gusts whipped a prescribed fire in January into a blaze that took nearly a week to contain. An independent investigation later found that, while conditions that day technically met the standards for a safe burn, the state had failed to have enough staff on site and a bulldozer for contingencies.
The incident stoked memories of a wildfire that ripped through the same area in 2011, destroying 1,600 homes and killing several people.
“The folks that are still here from 2011, they’re always nervous,” said Roxanne Hernandez, a Bastrop County resident. After the 2011 blaze, Ms. Hernandez completed a training program in prescribed fire and started carrying out burns on her 53-acre ranch. But for other residents, she said, “it’s back to Smokey the Bear: ‘Put it out!’ And that’s not the answer.”
Crews and managers trained in prescribed fire are in short supply in many places, foresters say. Many of the same people are also called upon to help extinguish wildfires.
“As the wildfire seasons get longer, those folks are gone for longer,” said Dan Porter, the forest program director in California at The Nature Conservancy, an environmental nonprofit. “When they come back, we may say, ‘Hey, would you like to go do a prescribed fire?’ Well, they’ve been out cutting line for four months and breathing smoke for four months. They need to go see their family and take a break.”
Ms. Quinn-Davidson of the University of California Cooperative Extension has hosted courses as part of a new program to train more people to lead prescribed fires in their communities. But with so many of California’s catastrophic wildfires taking place on federal land, only bigger policy changes and large-scale prescribed fire projects can stop further harm to the broader landscape, she said.
Last summer, the Forest Service’s chief, Randy Moore, restricted the use of prescribed fire on agency lands to make sure resources were available to fight wildfires. He also ordered a pause on allowing backcountry fires to burn if they provided ecological benefits and didn’t threaten homes or infrastructure.
The halt was temporary, but it was enough to make some ecologists fear that officials’ recent championing of fire could still go into reverse. If the goal is to return the land to an older ecological state, one in which frequent natural fires kept forests vibrant and resilient, then the scale of the task is staggering.
California is aiming to use prescribed fire on 300,000 acres of land annually by 2025. Far more of the state burned each year in centuries past, before intensive modern settlements transformed the landscape, scientists have estimated. Smoke and haze fouled the skies through much of summer and fall.
It may not be practical or desirable to go back to that world in its entirety. Still, as more human activity spreads into onetime wilderness, societies will have to learn to accept fire in one form or another, said Heath D. Starns, a fire researcher at Texas A&M University and president of the Prescribed Burn Alliance of Texas.
“It’s a process that really needs to occur, ecologically,” Dr. Starns said. “And our best option is to live with it, but to determine when, where and under what conditions fires happen.”
