Fighting fire with fire
When faced with a wildfire you have two options: stop it (known in the trade as “fire supression”), or let it burn. It’s not always an obvious choice.
Fire suppression changes the character of the forest, allowing some species to grow thick and choke out others. It allows more leaves, brush, and other dead tree matter to accumulate on the forest floor, providing copious fuel for when fire does start. Immature trees that might have been killed off by fire grow, creating denser forests with thinner trees interspersed with older, thicker ones. Denser forests with more abundant fuel mean that when fires are not successfully suppressed, they can quickly become bigger, hotter, and more destructive. In denser forests, fire travels up the trunks of the immature trees and into the crowns, where it rapidly leaps from tree to tree. Fire suppression is also dangerous: firefighters regularly die battling forest fires.
Fire suppression had been the default policy of the US Forest Service since 1910, when a devastating series of forest fires swept over Idaho, Montana and Washington, and of the National Park Service from its creation in 1916. By the 1950s, dissenting voices made themselves heard. Their concern was not that suppression would lead to bigger fires, but that it was upsetting the forests’ natural ecological balance. Scientists and ecologists who observed how fire had been a regular – and restorative – force in Florida became evangelists for the return of fire. In the early 1960s, controversy over the culling of elk in Yellowstone National Park prompted the Kennedy administration to appoint a group of outsiders led by Starker Leopold, a prominent zoologist, to recommend changes to wildlife management in the parks. Instead of protecting animals and forests for their own sake, Leopold and his colleagues argued in their 1963 report, the parks should be restored to the way they looked before Europeans came: “A national park should represent a vignette of primitive America.”
The gold seekers who crossed the Sierra Nevada into California in the 1840s “spoke almost to a man of the wide-spaced columns of mature trees that grew on the lower western slope in gigantic magnificence,” the report observed. “Today much of the west slope is a dog-hair thicket of young pines, white fir, incense cedar, and mature brush – a direct function of overprotection from natural ground fires… Animal life is meagre, wildflowers are sparse, and to some at least the vegetative tangle is depressing, not uplifting.” Deliberately set fire – a “prescribed burn” – was the most natural way to control the vegetation.
The Leopold report was more an expression of ecological advocacy than of science. Nonetheless, it catalysed a radical change in the approach to fire. In 1968 the National Park Service formally repudiated the 1930s-era policy that aimed to have all fires under control by 10am the next day; in 1978, the US Forest Service did the same.
But how to reintroduce fire? The forests were no longer the pristine, untouched expanses of the pre-European era; people lived, worked, fished, hunted and camped in them. They were vital to the livelihoods of countless loggers, fishermen, and hoteliers. Letting a fire burn that threatened to kill or displace people or do broad economic damage wasn’t an option. Forest managers would have to judge whether to let a fire burn or even when to deliberately set a fire.
Harry the Torch and the Midnight Ecologist
In the summer of 1988, when fire broke out in Yellowstone, that decision would fall to Superintendent Bob Barbee. One August day in 2014, I went to Bozeman, Montana, to visit Barbee. He retired from the Park Service in 2000, and at 78 years old was ruddy-faced, with a sweep of thinning grey hair and a gruff but steady voice. We chatted in his sitting room, which was filled with artifacts from his tenures in Yellowstone, Alaska and North Carolina, and furniture draped with Navajo blankets. Barbee’s love of the outdoors was readily apparent, from his hiking trousers to his stunning photographs of forests, lakes, and mountains decorating the walls.
“Barbee was a ‘Neanderthal running through the forest with his drip torch’ as he paraphrased it”
Barbee discovered this love while working summers as a ranger shortly after graduating with a degree in natural resources from Colorado State University. So when the National Park Service gave him the opportunity to work full-time in the parks, he jumped at it. In 1968 he became a natural resources specialist at Yosemite National Park in California. Shortly afterward, he paid a visit to Harold Biswell, an ecologist at the University of California at Berkeley and an evangelist for reintroducing fire to the parks. Biswell, decked out in field clothes, suggested they head out right away, and they spent the next three days setting fires.
At Yosemite, Barbee was tasked with adapting Leopold’s recommendations. He already knew that California owed its majestic sequoia trees to the fires that would periodically thin out the faster-growing white firs and allow the sequoias to thrive. At Yosemite, though, years of fire suppression had allowed the white firs to become dense. Barbee put together a plan for prescribed burning in Yosemite. Much of the public greeted it as barbaric; Biswell was nicknamed Harry the Torch, while Barbee was the ‘Midnight Ecologist’ a “Neanderthal running through the forest with his drip torch”, as he paraphrased it. But he pressed ahead, and one summer set a prescribed burn in the beautiful, famous El Capitán Meadow. The meadow’s hydrogeography had been altered years earlier by road building, which caused it to dry up and become a seedbed for pines; the Park Service was constantly cutting down those pines to keep the meadow intact. Barbee’s fire raced through the meadow for 45 minutes and killed every pine. The results were apparent by the following year: strawberries and azaleas were growing back where the pines had once choked them.
Barbee became superintendent of Yellowstone in 1983. Park policy since 1972 had allowed some natural fires to burn in limited areas that were then allowed to expand. Whether a fire was left to burn or was suppressed was based on a scientific analysis of fuel load, weather conditions, moisture content, and the proximity of valuable structures. Over the next 15 years, there were 235 fires ignited by lightning that consumed 34,000 acres (of a 2.2-million-acre park); 1981 being the worst year, with 20,240 acres burned. It helped that those years were relatively moist, reinforcing the belief that rain would in reasonable time extinguish almost all naturally ignited fires.
On 14th June, 1988, a lightning strike started a fire in Montana, just outside the park’s northern border.
In the following weeks, lightning started other fires. In keeping with Park Service policy, Barbee decided to let the fires burn while monitoring them. But the fires’ behaviour took Barbee and his staff by surprise. The moisture they expected didn’t materialise; the summer became one of the driest on record in the park, and powerful winds blew all summer long. Fires usually die down at night, but that summer they burned fiercely after the sun went down.
“I kept hoping maybe Gaddafi would do something outrageous, but he didn’t. So the media all came to Yellowstone”
Then there was the fuel factor. The park’s ecological staff had studied the rings of the park’s oldest trees and knew that the area had seen massive fires in 1705 and 1850. The evidence was visible from the air, as the trees that had grown back after those events looked different from the surrounding trees. Fires had been routinely suppressed since the late 1800s. In the 1960s Yellowstone began prescribed burning and allowing natural fires to burn. Nonetheless, the forests had grown thick with fuel.
By mid-July, Barbee changed tactics: all fires would be suppressed. Some of his scientific staff, anxious to study the effects of the fire on the forest’s ecology, resisted, but by then the fires had grown beyond their control. Forest staff had bulldozed firebreaks or set backfires to stop the flames from spreading, but high winds were blowing embers across roads, streams, and firebreaks. Fires spread by as much as five to ten miles per day. By 20th August, 165,000 acres were burning and the black clouds of smoke resembled a nuclear mushroom cloud. By early September, fire was approaching the Old Faithful Inn, the largest log structure in the world. Barbee sat down with the fire commander and said, “We’ve got the Sistine Chapel here. Losing the Old Faithful Inn is not an option. If we lose it I’m dead meat, and so are you.” Three days before the fire arrived, firefighters soaked and foamed the building. The fire destroyed seventeen nearby buildings and exploded a fuel truck, but the inn survived.
Barbee’s staff had predicted that natural fire would consume at most 40,000 acres that year; a total of 248 fires in Yellowstone and environs eventually burned more than one million acres, a PR nightmare for the Park Service. “I kept hoping maybe Gaddafi would do something outrageous” to draw the media’s attention, Barbee later recalled, “but he didn’t. So they all came to Yellowstone.”
Photographs from the 1988 Yellowstone fire:
Let it burn
The public and politicians had never understood why the Park Service would welcome fire, especially in Yellowstone, the nation’s oldest and most beloved national park. In August, NPS director William Mott declared a freeze on all prescribed burning in national parks. That September, a group of congressmen petitioned Ronald Reagan to force the NPS to forsake prescribed burning, or what they derisively called “Let it burn”. The park had become a vital source of tourist revenue for western states, and in addition, many saw the policy of prescribed burning as endangering the economic vitality of the logging and tourism industries. Some scientists were also critical; one compared the policy to “making incantations to the Greek God Zeus”.
The science behind prescribed burning is sound; what can’t be changed is the inherent complexity and unpredictability of fire. This became searingly apparent in 2000 in the Frijoles Canyon that cuts through Bandelier National Monument, just south of the town of Los Alamos, New Mexico. Park officials fretted that the worst drought in 60 years had made the region ripe for a massive wildfire. An arsonist was on the loose and had already started one major fire in 1998. And everyone worried that a massive fire might damage the nuclear weapons laboratory in Los Alamos. So, intent on reducing the fuel load and avoiding such an event, the Park Service began a prescribed burn on 4th May on the slopes of Cerro Grande Peak above the canyon by igniting grass with petrol spilled from drip torches.
Within a few hours, the fire had begun to spread beyond its prescribed boundaries. By the next day, it had changed from a prescribed burn to a wildfire. To contain the blaze, firefighters built backfires along its western boundary to keep the flames from spreading to the heavily wooded areas farther down in the canyon.
When winds began to strengthen, pushing the flames from that backfire into the thickly wooded areas of the canyon, the Park Service called in helicopters to drop retardant on the spreading blaze. That fire, too, got out of control; flying embers ignited spot fires to the east, closer to Los Alamos. Flames were soon racing toward the town at nearly a mile per hour. On 10th May, New Mexico governor Gary Johnson ordered the town’s 11,000 residents to evacuate. Blowing embers lit spot fires on the 43 square mile lab complex, prompting the Department of Energy to send teams to monitor for radiation leaks from the nuclear weapons laboratory (none occurred). Eventually, 1,400 firefighters and 16 tanker aircraft and helicopters were called in to battle a blaze originally intended to consume 900 acres. It burned 48,000 and destroyed more than 200 homes.
Investigations began almost instantly. Bruce Babbitt, the interior secretary, blamed “seriously flawed” calculations by the National Park Service. That and subsequent reports faulted park personnel for inadequate attention to changes in wind forecasts and failing to have adequate firefighters and tankers on hand to contain the fire should it get out of control. They also, according to some critics, had too little experience managing prescribed burns.
For the people charged with managing forests, deciding whether to let a fire burn or to suppress it carries enormous personal consequences. In Yellowstone in 1988, outraged residents and business owners nicknamed Barbee “Barbee-Que Bob” and a cartoon featuring burning teddy bears labeled “Barbee Dolls” appeared in a Montana newspaper. Barbee was used to making unpopular decisions, from the prescribed burns in Yosemite to blocking motel development in Cape Hatteras. It was not, he recalls, a job for someone who worried a lot about how his decisions would be viewed.
After the Cerro Grande fire, Roy Weaver, the superintendent at Bandelier, was vilified and threatened with the loss of his pension, though a board of inquiry recommended against any disciplinary action. Weaver, who retired shortly afterward, later said “Things happened that we couldn’t or didn’t anticipate. And that we couldn’t control.” Barbee sent him a sympathetic letter of support. Many other park personnel had been in the same position, he said, and “there but for the grace of God go I.”
The megafires to come
Today, Barbee is convinced that nothing could have prevented the fires of 1988, even if they had tried to suppress them earlier. There was a confluence of events that made a repeat of the fires of 1705 and 1850 inevitable.
Officially, natural fire and prescribed burns remain central parts of federal forest management. But the Yellowstone and Cerro Grande episodes illustrate the risks that the people tasked with carrying out those policies must run. The same complexity that makes management by fire suppression dangerous in the long run also makes the use of fire unpredictable in the short run. Countless things can cause fire to get out of control, from unexpected wind changes, lack of precipitation and lightning to the underlying characteristics of the terrain.
The ferocity of the Yellowstone and Cerro Grande fires was due at least in part to the lack of fire in preceding decades. Yellowstone was established as the first national park in 1872, and in 1886 the army took over responsibility for fighting fire there. Suppression remained the default policy until the 1970s. “In 1988, you burned off a century’s worth of buildup,” says Stephen Pyne, a fire historian. Tom Swetnam, an expert at divining the history of fire from the scars that ancient fires left in the rings of centuries-old trees, believes large fires occurred roughly every six years in the eighteenth and nineteenth centuries around Los Alamos, but there had been no large fire since 1881.
“If you set a prescribed fire or let a natural fire burn and that escapes, that could be a career-ending move”
If the calculations of Swetnam and Jennifer Marlon, creator of the “global charcoal database”, are right, and the past century has been unusually quiescent in terms of fires, then the implication is that there will be many megafires ahead. Experience seems to bear that out: the past decade has witnessed more fires topping half a million acres than in previous decades. This is not simply the consequence of climate change, but the legacy of fire suppression.
Unfortunately, knowing this doesn’t tell us what to do. Should we encourage more fires to eliminate the fire deficit? Or be more alert and faster at putting out fires to prevent a megafire from erupting? Science supports the former course of action; day-to-day reality, the latter. For those whose job it is to manage the forests, the consequences are highly asymmetric. If letting a fire burn accomplishes the desired goal, the result will be a healthier forest and fewer megafires many years later. Few people will notice the healthier forests, fewer still the absence of fires. If the fire gets out of control, the consequences are millions of dollars’ worth of damage, lives potentially lost, and a gauntlet of television cameras and outraged congressmen demanding answers. Add to that the fact that prescribed burns and mechanical thinning of forests, both natural ways to reduce fuel and encourage natural growth, are expensive, and the temptation to suppress rather than burn becomes overwhelming.
Suppression in turn induces behaviour that makes the choices harder. The temporary moratorium on prescribed burns in western national parks following the Yellowstone fires led to increased land development nearby compared to areas where prescribed burns continued. Such development makes it more costly to let fires burn. Pyne attests to this, saying that for most forest managers, there’s a strong default in favour of suppression: “If you set a prescribed fire or let a natural fire burn, and that escapes, that could be a career-ending move. If you attack a fire and it escapes, you’ll be applauded as a hero.” He quotes a forester he met at Sequoia National Park saying, “I go to work every day knowing that a wind shift could land me in jail.”
Further reading: Greg Ip is the author of Foolproof: Why Safety Can Be Dangerous and How Danger Makes Us Safe, published by Headline
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