Prescribed burns aim to increase wildfire resilience, firefighting safety
By Ashley Ahearn
The U.S. Forest Service truck shuddered over the dirt road as Sara Billings, fuels assistant fire management officer at the Methow Valley Ranger District, drove up into the Okanogan/Wenatchee National Forest outside of Winthrop last week. She was visiting a prescribed burn that was underway in the 8 Mile Creek drainage near the Chewuch River.
As Billings approached the burn, truck lights flashed and smoke billowed across the road. Dozens of firefighters lined the perimeter of the prescribed burn, standing alert in their Nomex flame-retardant gear, on the lookout for a stray spark or ember that could trigger a wildfire.
Others walked through the forest using drip torches to ignite the underbrush. Flames licked around the bottoms of ponderosa pines and Douglas fir and crackled along the forest floor.
The Forest Service will burn 450 acres in this section of the forest. It’s one of four areas in the Methow Valley targeted for prescribed burns this spring, including sections near the Goat Creek Sno-Park, the upper Rendezvous and the Urchin timber sale up Cub Creek.
Prescribed fires, or controlled burns as they’re sometimes called, are an increasingly relied upon method for improving wildfire resilience and forest health in the west. In the Methow Valley, the Forest Service aims to burn 3,000 acres of forest each year, but it has a very short window — in the spring and fall — in which it can accomplish those burns safely.
A huge amount of planning goes into each prescribed burn, sometimes taking years of modeling, fuel and forest analysis and permitting to make it possible to conduct a burn like the one at 8 Mile last week — and that’s to say nothing of the ever-changing on-the-ground weather conditions at the time of a proposed burn.
“I spend a lot of hours looking at weather, coordinating resources, worrying about the budget and how much I’m spending and if we’re going to be successful,” Billings said. “I’m always excited to see plans come to fruition. It’s a lot of hard work and it takes a lot of time but it’s awesome.”
Living in the WUI
Since 1990, 60 percent of new homes in Washington, Oregon and California have been built in the wildland/urban interface (WIU) — the area where houses or other development meet and intermingle with wildland vegetation, according to a report by Headwaters Economics. Residents of the Methow Valley are familiar with this trend. As more people build homes in forested areas, the risk of wildfire — and the urge to suppress it — have increased over the years. But that approach to forest management is shifting.
For many forests in the west, wildfire is a natural part of the landscape and some plants are specifically adapted to frequent, low-intensity burns that reduce underbrush and low-level growth in the understory of the forest. When that natural process is suppressed, forests become denser and forest floors become lined with so-called “ladder fuels,” or mid-height growth, that can transmit a small fire from the forest floor up into the forest canopy where it can amplify to a hotter, more intense wildfire that can spread over thousands of acres.
“We have been extremely successful at fire suppression over the past 100 years, almost too good,” Billings said. “We’ve deferred the risk. We’ve kept fire small and controlled them and now fuel loading is getting higher and it’s a lot riskier to fight fire around here.” Average firefighter fatalities rose from 9 per year in the 1970s to 19.3 per year in the 2000s, according to research from Headwater Economics.
Mike Liu, Methow Valley District Ranger, said that prescribed burns reduce fuel in the forest, lowering fire intensity and making it safer and easier to fight wildfires that may ignite in the area in the future.
“By treating acres now the cost per acre on a prescribed burn would be less than having to fight a large wildfire later on,” Liu said.
Billings said that it costs an average of $150 per acre to conduct a prescribed burn, a relatively low cost compared to what is spent fighting wildfires each year.
Federal agencies have averaged $3.7 billion in fire suppression spending annually over the past 15 years. Overall, the Forest Service now spends half its annual budget fighting wildfires, which leaves less funding for fire prevention work, such as the prescribed burns being conducted in the Methow Valley this spring.
How would you like your smoke?
Conducting prescribed burns does not guarantee the prevention of wildfires in the future and smoke from prescribed burns can have negative health effects. Children, the elderly and people with respiratory or cardiopulmonary conditions are at highest risk. Public health experts recommend setting air conditioners to re-circulate indoor air, installing HEPA filters and limiting exertion when air quality is bad.
However, according to research from the University of Montana and the Forest Service Fire Science Lab in Missoula, wildfires release 17 times more smoke, on average, than prescribed burns and because they burn more intensely, wildfires also emit more aerosols and fine particulate matter per ton of fuel burned than prescribed fires.
“When it comes to the Methow people are for the most part very familiar with smoke in the air and they’ve been through some pretty excessive wildfires in the recent past,” Billings said. “So for the most part, they’re supportive of having some smoke in the air for a couple of days in the interest of having less severe fires later on.”
The Forest Service coordinates with local groups to avoid conducting burns during high tourism periods. An 800-acre burn was scheduled for the weekend of the Sunflower Marathon earlier this month above the Goat Creek Sno-Park, but it was postponed to maintain air quality for the runners and other visitors to the valley. The ’49er Days weekend was also a no-burn period.
This week, the Forest Service plans to continue burning in the 8 Mile drainage and perhaps in the Upper Rendezvous, if conditions are good.
“This will most likely be the last week that we pursue prescribed fire activities on the district and we’ll most likely be making a shift to fire suppression readiness after Memorial Day,” Billings said in an email. “However if weather continues to be favorable, we’ll keep burning.”
About that smoke …
The Methow Valley Ranger District completed the 450-acre 8 Mile burn on Monday (May 21), but the U.S. Forest Service said in a press release that forecasted winds were weaker than expected. “With a high-pressure system over the valley today (Tuesday, May 22), the smoke that settled into the valley last night is taking some time to lift,” the Forest Service said. “The unit will continue to produce some smoke as larger fuels burn out.”
“The district initiated the burn last week under more favorable conditions. Unfortunately, the rain prevented us from completing the burn; but did not put the prescribed fire out,” said Methow Valley District Ranger Mike Liu. “Consequently, we had to take advantage of the first opportunity we had to complete the burn and accomplish our objectives and keep the fire within the unit boundary.”
“There is a weather disturbance predicted for Wednesday (May 23), so I don’t expect the smoke impacts to last very long,” Liu added. “The district does not anticipate doing additional prescribed burning until this fall.”
For smoke-related information see wasmoke.blogspot.com.