Burn it quick.
Burn it often.
Save the forest.
The evidence continues to grow that vigorous use of prescribed fire — especially when combined with thinning projects — remains the only way to prevent sweeping changes in unhealthy, fire-prone forests throughout the west.
Unfortunately, this year’s record-breaking drought forced the Forest Service to all but skip a season of controlled burns, since the fall never got wet or cool enough to allow a safe season of managed fires.
However, a growing number of studies have underscored the need to embrace prescribed fires throughout the region — despite the short-term political and economic risks. One of those risks centers on the refusal of forested communities like Payson and Show Low to adopt building codes for fire-harden buildings and make it much safer to employ prescribed fires close to those communities.
Not only can prescribed fires prevent the wholesale destruction of the region’s extensive ponderosa pine forests and the communities they surround — frequent, controlled, low-intensity fires can actually reduce the release of heat trapping carbon into the atmosphere, according to the research.
That finding could boost the quest to get more federal money to manage fires and thin forests, giving the incoming administration’s emphasis on climate change and the reduction of greenhouse gases.
Unfortunately, Arizona communities have been setting records for heat and drought all year, with a dry winter and an early start to the fire season forecast.
Fortunately, this year Congress enacted the National Prescribed Fire Act, which set aside $300 million to increase the number of controlled burns, including incentives for large-scale burns. The act also requires state air quality agencies to allow larger burns, especially in the winter months. In 2018, a survey determined that 234 million acres of forest are at high risk of dangerous fires — but the federal land managers in the past decade treated less than 3 million acres nationally.
Wildfires in the west this year burned more than 7 million acres, consumed more than 10,000 homes and killed dozens of people, further underscoring the need for action.
However, the nation’s most ambitious forest restoration effort in history has been nearly stalled for the past decade — mostly for lack of a market for the biomass from small trees and debris that makes up half the material in need of removal. The 4-Forest Restoration Initiative has in the past decade thinned about 150,000 acres. 4FRI has also treated another 442,000 acres with fire, but most of those are naturally cased fires in the cool months that fire managers have let burn in a contained area. A much smaller percentage of those fires have been intentionally planned and set prescribed fires.
But even if you include all those managed fires, the Forest Service has treated only a fraction of the 6-million-acre project area. The mechanical thinning efforts were supposed to cover 50,000 acres annually, five or six times the actual pace.
Ideally, the Forest Service would first thin tree densities from the current average of about 1,000 per acre to more like 100 per acre before returning to widespread and frequent use of prescribed fire. In a dense, unhealthy forest, a prescribed fire can more easily escape control. Even if it remains within the planned boundaries, a prescribed fire in a thick forest can either burn so hot it kills the roots of the big trees or climb the fuel ladder of the little trees into the branches of the big trees — causing a much more dangerous crown fire.
Nonetheless, the research clearly documents the need to rely much more heavily on prescribed fires during the cool, wet months — despite the risk that a fire will burn hotter and faster than planned.
So here are some of the latest findings:
Prescribed burns reduce carbon emissions
Paradoxically, frequent prescribed fires on millions of acres of forest will actually reduce the release of heat-trapping carbon into the atmosphere, according to a study by researchers from the University of Northern Arizona.
Climate experts say that the buildup of heat-trapping gases in the atmosphere is one of the things driving a rise in global temperatures that has resulted in both more severe drought and more intense wildfires.
But low-intensity fires will release an average of 18 to 25% less carbon than letting the more intense wildfires continue, according to the analysis of satellite images and computer models in 11 Western states from 2001 to 2008. In some forested systems, prescribed fires will reduce emissions by 60%.
High-intensity fires not only burn hotter and send smoke higher into the atmosphere, they’re also more likely to consume old growth trees — which have each been storing carbon for 600 or 800 years.
“By applying prescribed fire to manage surface fuels, when subsequent fires occur they will be less intense and tree mortality rates will be lower than under high severity wildfire conditions. With more living trees, the forest will sequester more carbon,” concluded study co-author Matthew Hurteau.
High-intensity fires turning forest into grasslands
The current plague of high-intensity wildfires is causing permanent changes in the landscape — with many forests unable to recover from a wildfire, according to a study led by researchers from the University of Colorado Boulder.
The study examined 22 burned areas in the Southern Rocky Mountains to determine whether the ponderosa pines and Douglas fir that once dominated those burned areas recovered.
To their dismay, researchers found that in 80% of the burned areas — especially at lower elevations — the forest has not returned, even decades later. Instead, the forest has been replaced by grasslands and chaparral. By 2050, given current wildfire and climate trends, perhaps only 5% of the forests in the southern Rocky Mountains will be able to recover after a fire.
The researchers — including teams from Northern Arizona University — counted pine and fir saplings in areas that burned 15 or 25 years ago. In 80% of the plots, they found no pine seedlings, according to the study published in Global Ecology and Biogeography.
The researchers concluded it’s already too late to avoid major changes in the forests, based on the predictions of multiple climate models. Even if human beings reduce carbon emissions and therefore average global temperatures, less than 18% of the forest types studied will be able to bounce back after a wildfire. If the rate of emissions continues to increase, only about 3% of ponderosa and 6% of Douglas fir forest will be able to recover from a wildfire.
Remove barriers to prescribed burns
Land managers must work much harder to remove barriers to prescribed fire, according to a study led by Stanford researchers published in Nature Sustainability.
“We need a colossal expansion of fuel treatments,” said study lead author Rebecca Miller, according to a summary of the research on the Science Daily website.
The study found that prescribed fires rarely escape their planned boundaries and offer broad ecological benefits, including reducing the spread of disease and insects, increasing species diversity and reducing the risk of much more damaging, high-intensity fires.
California alone needs to treat 20 million acres with prescribed fire.
California land managers doubled the areas planned for prescribed burns between 2013 and 2020 — but at least half of the planned projects never took place due to concerns about smoky air, outdated regulations and limited resources, the researchers concluded. Concerns about liability and financial responsibility in case a prescribed fire gets lose and does damage have also smothered efforts to increase prescribed fires.