Fire Wars

On July 7, 2022, at Yosemite National Park, someone started a fire on the Washburn Trail, at the southwest corner of the world-famous Mariposa Grove of giant sequoia trees. Sequoias are the most massive single-stem plants in the world, some growing taller than 300 feet and exceeding 35 feet in diameter. They can live more than 3,000 years. Preserved on public lands, they exist as wards of our government, but the older ones have been around longer than any government, ever. They occur naturally in about 70 relatively small groves along the western slope of California’s Sierra Nevada mountains, and they have become the focus of great concern. Since 2020, between 13 and 19 percent of them have been killed or are dying from large fires driven by climate change.

The July blaze, known as the Washburn fire, was human-caused; whether accidental or intentional is unclear. With temperatures in the 90s, flames spread quickly through the woods, where trees already killed by drought and beetle infestations had a moisture content equivalent to that of kiln-dried lumber. Fire crews, engines, and aircraft streamed into the park and the neighboring Sierra National Forest. The fight lasted three weeks. On some days violent convection columns like brown thunderheads boiled into the sky. A tree branch, lifted hundreds or thousands of feet by one of these updrafts, narrowly missed two firefighting aircraft as it plummeted back to earth.

The good news was that firefighters kept the blaze out of most of Mariposa Grove and the nearby village of Wawona. None of the 500 or so mature sequoias in the grove perished in the flames. Yosemite’s fire management chief, Dan Buckley, credits this to decades of work to reduce a buildup of fuels—younger trees of other species, deadwood, and brush—that had accumulated in Yosemite forests under an eight-decade government policy of extinguishing all wildland fires. This policy, now rescinded, actually worked against fire control, eliminating the frequent, low-intensity flames that had flickered through sequoia groves every 15 years, on average, consuming fuels on the ground with little harm to mature trees. In the twentieth century Yosemite’s staff responded to the consequences of their own firefighting efforts by cutting down thousands of white firs and incense cedars that grew up around the sequoias in fire’s absence, and after 1970, by repeated controlled burning.

That work paid off during the Washburn fire, but its success occurred against the background of a lawsuit, filed less than a month before, challenging a new round of tree cutting at Yosemite. An environmental group, Earth Island Institute of Berkeley, California, sued to stop the National Park Service’s use of chainsaws and logging equipment to thin trees in strips along 40 miles of roads and trails to create strategic fuel breaks that firefighters could safely enter and stand their ground.

Behind the controversy was a larger question: Given human-caused climate change and alterations to forests from decades of fire suppression, is it appropriate to use such unnatural means to protect natural treasures? It turns out that this question is not particular to the era of climate change. Rangers, scientists, and conservationists have been fighting over how much and what kind of modifications of nature ought to take place in national parks since at least the 1920s.

The Park Service refers to the present tree thinning as “biomass removal.” Earth Island Institute denounces it as “commercial logging” because some of the trees have been sold to lumber mills to defray costs. The laws and policies of other land management agencies such as the U.S. Forest Service provide for the sale of timber, but commercial exploitation of natural resources is inconsistent with the preservationist mission of national parks. In its defense, the Park Service argues that the cutting is done not to make money, but to stop the new class of climate-driven “mega fires” from destroying the park.

Behind the argument is a lot of history, from which both sides draw conflicting conclusions about how much we should tinker with protected ecosystems in order to save them. The Park Service points to thousands of years of human management of nature in Yosemite—fires ignited by Indians, then decades of government fire suppression, the cutting of trees grown up under fire suppression, and later, attempts to reintroduce natural fire. On the other side, the man behind Earth Island Institute’s lawsuit, research ecologist and maverick environmental activist Chad Hanson, counters that human alteration of forest regimes amounts to a scientific conspiracy to soften resistance to commercial logging. Hanson says that instead of thinning forests, which he believes just makes fires worse, we should stop all logging and fall back to hardening homes and landscapes in populated areas against wildfire. Let the fires go, he says, and nature will work everything out. But Hanson’s confidence in the balance of nature is not shared by other scientists working on sequoias, forests, and fire.

In his bestseller Blink, Malcolm Gladwell noted that we see things most clearly in a quick, initial take. If this is true elsewhere, it does not work on forests. The forests of Yosemite today are a product not only of nature but of history. Trees are made of history. You can count good and bad years in their growth rings and fire years in charcoal scars healed over and buried deep in their trunks. Fire years are also recorded in layers of charcoal at the bottom of forest ponds.

Early explorers left accounts of Indigenous people’s use of fire in Yosemite and much of the rest of North America. Yosemite’s Indians burned to open up the woods for hunting and stimulate fresh growth of forage for game. They set fires to harvest bulbs, roots, acorns, and other foods and to cultivate sprouts on plants used to make arrow shafts, fish traps, and basketry. So pervasive was indigenous fire that ecologists have come to understand the structure and distribution of post–Ice Age vegetation of North America as having coevolved with it.

With the displacement and genocide of Native Americans in the nineteenth century, unregulated logging unleashed mayhem on American forests. Timber was dragged out of the woods by wood-burning steam winches and locomotives. Wood fires heated buildings roofed with wood shingles. Mountains of logging debris were left to dry in the sun. So, wherever logging went, catastrophic fire followed. A series of spectacular infernos that killed thousands of people between 1871 and 1910 focused attention on wasteful use of forests. In 1905 a new federal agency, the U.S. Forest Service, stepped into the vacuum of authority over forest conservation and wildfire. Its first chief, Gifford Pinchot, made it clear where firefighting stood in his priorities. “Officers of the Forest Service, especially forest rangers, have no duty more important,” he wrote. This doctrine remained in force for much of the twentieth century.

Native American fire never really disappeared. Merging with European modes of agricultural burning, it continued as a folk tradition in some parts of the country and was resurrected on some Indian reservations. But in the main the United States waged effective war on fire, and annual acreage burned drastically declined. Fire is one of nature’s important recyclers, releasing nutrients stored in plants back into soil for use by other plants. Without it, photosynthesis kept turning sunlight into wood, leaves, bark, and roots, and production of plant matter quickly outstripped its dissolution back into the soil.

Stopping fires was not the only wrongheaded manipulation of nature in national parks. For the supposed benefit of recreational fishers, early rangers transplanted nonnative fish to lakes and streams, where they laid waste to aquatic life. Wolves, coyotes, and mountain lions were hunted down, and consequently their prey, such as deer and elk, overpopulated parks. Park boundaries were drawn up without a thought to migrations of wildlife across them. Bears were allowed—even encouraged—to feed on tourists’ food, resulting in dangerous human–bear conflicts.

In the 1920s, as the nascent science of ecology came into its own, groups such as the Ecological Society of America expressed concern over the alteration of natural conditions in national parks. Park Service biologist George Melendez Wright argued that mere protection would not repair damage done by mismanagement. To restore natural conditions would take deliberate manipulation of nature.

Wright died young in an auto accident, and by the 1950s his successor in advocating purposeful manipulation of ecosystems to restore their health was Berkeley wildlife biologist A. Starker Leopold. In the absence of predators the government had wiped out, for instance, Leopold said the Park Service might have to artificially control the numbers of their prey, such as deer and elk, lest their competition for food destroy park vegetation. And the parks should reintroduce fire in its ecological role, Leopold argued.

Leopold’s recommendations, laid out in a 1963 white paper known as the Leopold Report, made him the Park Service’s principal adviser on what would later be called “restoration ecology.” His advocacy of fire was influenced by fellow Berkeley forestry professor Harold Biswell, who had been conducting controlled burns on private land since 1951. Biswell was so avid about fire he acquired the nickname “Harry the Torch.”

In 1961 two members of the pro-fire Berkeley circle around Leopold and Biswell compared old panoramic photographs of Yosemite Valley from the 1860s onward to newer ones taken from the same locations. The changes were stunning. Where the old photos showed forests of widely spaced trees broken by open areas, later images captured the same forests now densely packed with trees and invading former meadows. Similar “repeat photography” studies elsewhere in California, Nevada, Wyoming, Arizona, and South Dakota rendered similar results—a continental-scale advance of trees and brush.

Sensing a moment of opportunity, Leopold and Biswell set out to bring fire back to the sequoia groves of Yosemite and, to the south, Sequoia and Kings Canyon National Parks. Beginning work on university land just outside Sequoia National Park in 1964, Biswell found tangles of trees, brush, and debris built up during more than a half-century of fire suppression and directed workers to cut, pile, and burn it before lighting ground fires in order to avoid incinerating sequoias. On the other side of the boundary, researchers inside the parks did the same thing.

Nor was this cutting new. Almost as soon as they started putting out fires, Yosemite’s early keepers had noticed trees of other species growing up to block tourists’ views of the sequoias. In 1933 the park’s superintendent ordered workers to cut and haul away more than 3,000 trees—mostly white fir—to restore scenic vistas in Mariposa Grove. In the late 1960s, in consultation with Biswell, the park’s new chief of resource management directed cutting, piling, and burning of what he described as “tens of thousands” of trees to prepare Mariposa Grove for its first controlled burns.

In 1971 Biswell’s graduate student Jan van Wagtendonk, who became the park’s research scientist, contributed formulas to professionalize controlled burning into more scientifically rigorous “prescribed burning.” From that point to this year’s Washburn fire, portions of Mariposa Grove were burned as many as six times. Still today, before a burn is ignited, fallen branches and other fuels are piled away from the trunks and root systems of the giants.

One thing that cannot be said of Mariposa Grove is that it is untouched by humans. But a vision of a primeval world before the compromised present is what people expect at a national park.

To the extent that George Wright’s and A. Starker Leopold’s purposeful manipulation of wildlands to restore natural conditions was generally popular in the Park Service, it did not delight some conservationists in the “wilderness movement” whose goal was to preserve remaining areas of roadless backcountry free of human domination and control. When the Leopold Report was published in 1963, wilderness advocate and Park Service biologist Adolph Murie called it “the most extreme anti-park statement I have yet encountered.”

Howard Zahniser, executive secretary of the Wilderness Society and principal author of the Wilderness Act, signed into law the following year, called Leopold’s ideas “a serious threat to wilderness.” Such places “should be managed so as to be left unmanaged,” argued Zahniser in an editorial in the Wilderness Society’s magazine. He then summarized his position: “With regard to areas of wilderness we should be guardians, not gardeners.”

Earth Island Institute’s Chad Hanson subscribes to this sort of hands-off philosophy. Hanson says that with regard to the operation of public lands there are three kinds of people: those who believe nature is there to exploit for profit, those who love nature but don’t trust nature to look after itself, and those who love nature and trust it to work everything out. He’s in the latter category, he says.

The problem with Hanson’s purism is that it’s not 1963 anymore, and nature isn’t all that natural. The loss of as much as a fifth of all living sequoias to fire over the past two years suggests that if we want to keep some of the world’s largest living things, we may not want to put total trust in a hands-off approach.

Hanson is clearly intelligent and dedicated, but talking to him is like entering a parallel world where everything is opposite. He is not worried about the survival of sequoias or other forests in the era of mega fires. On the contrary, he has written on the benefits of mega fires. Asked about the dissonance between the idea that there is no threat to sequoias and the number of them lost to fire in two years, Hanson disparages the mortality estimates and the scientists who made them, calling the effort “a back-of-the-cocktail-napkin thing.” One of the scientists he dismisses has been working on sequoias since Hanson was a grade-schooler. Hanson has yet to produce his own figures, but he says he’s working on it. Meanwhile he estimates that the actual loss of mature trees is “probably about seven or eight” percent. He does not say how even that level of mortality could be sustained if it continues but points enthusiastically to the numbers of sequoia seeds that germinated in the fires’ wake. Of course a sequoia seedling is not a millennia-old giant.

Regardless of Hanson’s idyll, human manipulation of nature paid off in Mariposa Grove during the July blaze. When a fire burning in heavy fuels runs into an area where fuels have been reduced, the flames tend to “lie down.” Park Service ecologist Garrett Dickman, who had been directing the tree cutting, witnessed this effect during the Washburn fire in areas that had been repeatedly subject to prescribed burns. There, flame lengths were about two feet, while in neighboring areas they reached more than 150 feet into the air. This was reminiscent of what happened in the KNP Complex fires in Sequoia and Kings Canyon National Parks the previous year, where the successful effort to keep the fire out of the sequoia grove at Giant Forest was advantaged by a two-lane highway bordered by an area that had seen half a century of repeated prescribed burns.

Control is a term scientists use for an untreated group of experimental subjects, such as those receiving a placebo in a medical trial. There happens to be a control group of giant sequoias that can aid in evaluating whether human intervention helps save the ancient trees. These groves, located in the backcountry without roads, fuel-reduction projects, or prescribed burns, have not fared well. In fact, most of the sequoias lost to recent fires were in backcountry groves. Ninety-five percent of Yosemite is designated wilderness under the Wilderness Act, which prohibits use of machines such as logging equipment. Management of fires in Yosemite's wilderness is limited to allowing some unplanned human or lightning caused ignitions to burn, when conditions are favorable, to shape vegetation, improve wildlife habitat, and prevent larger conflagrations down the road. The recent fuel-break work has been taking place outside the wilderness and covers less than 0.5 percent of Yosemite’s land area.

Hanson, who has a law degree from the University of Oregon and a doctorate in ecology from U.C. Davis, alleges that the Park Service dodged a full review and public comment on the effects of its tree cutting. The Park Service argues that the work is covered in a 2004 environmental impact statement and fire management plan, parts of which were updated in 2017. But a lot can change in nature and science in 18 years, and the plan called for removing only trees with a diameter of 12 inches or less, not the 20 inches specified in the present work.

Hanson also objects vehemently to the Park Service’s removal of trees that had grown in during fire suppression to block iconic views, such as that of the 3,000-foot granite prow of El Capitan from the road entering Yosemite Valley—a process of forest change already visible in the 1961 photo comparison study. The Leopold Report had called for just this sort of cutting to restore scenic vistas, drawing fire from Adolph Murie, who complained that by manicuring views Starker Leopold was trying to turn the national parks into Disneylands.

Categorically, the scenic vista program and the fuel breaks are both responses to the unintended consequences of fire suppression, but Chad Hanson lumps them together as a conspiracy to conduct commercial logging in the national park.

“They’re clear-cutting!” he says. “They’re selling these trees to logging companies, coming in and intensively logging old-growth forests.”

However, if the sight of loaded log trucks leaving Yosemite speaks of a new comfort in tinkering with nature, it is one that Leopold foresaw six decades ago, and particularly with the fuel breaks, a lot is at stake. To have witnessed the loss of as much as one-fifth of all living sequoias on their watch is heartbreaking for Dan Buckley, Garrett Dickman, and Nicole Athearn, Yosemite’s chief of resource management and science and Dickman’s boss. “We cannot stand by and do nothing,” says Athearn. “Doing nothing is doing something,” she adds, because human effects on climate and fuels would continue even if the rangers were to adopt Hanson’s hands-off philosophy.

Nevertheless, doing something in a hurry carries its own risks. The Bipartisan Infrastructure Law and Congress’s 2022 Omnibus Spending Bill provide almost $10 billion for wildland fire management, fire risk reduction, and research to agencies like the Park Service, Forest Service, and U.S. Bureau of Land Management. When the government gets fistfuls of money with orders to spend it fast, haste can make waste, as was the case with the billions in pandemic relief funds lost to fraud. In April 2022 in the Santa Fe National Forest, firefighters lost control of two prescribed burns that joined to become the largest wildfire in New Mexico history. Among the causes cited in the Forest Service’s investigation was pressure within the agency to accomplish a backlog of fuel-removal projects.

Notwithstanding the overwhelming proof to the contrary—including the 1961 Yosemite photo study—Hanson says there has been no broad increase in the density of North American forests from fire suppression. He says he would agree with fuel breaks along roads if the park service used only fire to create them. He does not oppose felling hazard trees that might fall on cars or buildings, but he wants the park to leave any trees felled to decay naturally on the ground, not haul them to a sawmill, pile and burn them, or chip them and truck them to a biomass power plant, as the park has done when the trees are not suitable for lumber. Of course leaving trees on the ground is in conflict with the very idea of a fuel break. But Hanson does not seem to hold himself responsible for the nuts and bolts of controlling fire, because outside of developed areas, he is not in favor of it.

Two days before the Washburn fire, the Park Service and lawyers for Earth Island Institute reached agreement on a temporary halt to the cutting at Yosemite pending a court hearing. After the Washburn fire, Dan Buckley, Garrett Dickman, and Nicole Athearn spent August of 2022 waiting for a federal judge to render an opinion and praying there wouldn’t be another fire in the big trees. On the wall above Dickman’s desk hangs a drawing by his five-year-old nephew of a huge sequoia. Dickman and his colleagues don’t believe the trees will save themselves without some help. Chad Hanson does. There is something deeper here than facts and figures, though. It is how people who love the natural world deal with foreboding, even grief, about the future of life on earth. Some do it by fighting what may be a losing battle, some by downplaying the need to act and placing their trust in the Magna Mater, Mother Nature, that all-knowing deity of the ancient world.