Those Sequoias Didn’t Just Get Lucky

This is what preparing for wildfires looks like.

A firefighter works to save a giant sequoia tree in Yosemite
Noah Berger / AP

In 1901, the naturalist John Muir wrote in this magazine that no description could capture the majesty of the giant sequoia. Of course, that didn’t stop him from trying: Muir spent some 17 pages ruminating on the tree, which he called “nature’s forest masterpiece, and, as far as I know, the greatest of living things.”

This week, Americans watched as the very same specimens that so enchanted Muir more than a century ago came under threat of wildfire. The Washburn fire, first reported nearly a week ago, continues to burn in Yosemite National Park; it has swept over more than 3,000 acres and forced evacuations of several nearby areas. The burn was first reported from a trail near Mariposa Grove, famed for its 500 towering ancient giant sequoias.

Thankfully, the rare and historic trees appear to remain safe for now: Not a single sequoia has been lost, Garrett Dickman, a forest ecologist for Yosemite, told me Tuesday evening. Dickman, who is also a firefighter, checked up on the grove himself earlier this week, providing “first aid”—water for their roots and to cool down their burns—to sequoias in need.

Should the good news hold, and the trees escape alive, their survival isn’t mere luck: The National Park Service has spent decades thinking about the fire management of this particular grove. This week’s scare is a tentative case study in how wildfire preparation can help stave off destruction—an important lesson in the value of planning in our new age of unruly fire, as a consequence of climate change.

Mariposa Grove has an almost mythological status in the American landscape. “This is like watching the Sistine Chapel catch fire,” Alfred Runte, an environmental historian and the author of ​​National Parks: The American Experience, told me. Runte also cited a less theoretical analogue: the Notre Dame fire of 2019.

“The National Park idea was basically our answer to Europe,” he explained. “We responded by saying, ‘Well, you have the great human-made wonders—you have the great cathedrals; you have the Colosseum; you have those wonderful places. But we, the American people, have these great natural wonders.” In the 1850s, the British even accused the trees at Mariposa Grove of being fake, Runte said. “We took umbrage to that.” In 1864, President Abraham Lincoln signed legislation protecting the grove.

Today the protection of the grove’s sequoias is a priority for the park. “If we were to rank, it’s going to be life, health, safety, communities, and then sequoia groves,” Dickman told me.

Yosemite has done controlled burns in the grove itself since the 1970s to conserve the trees. Controlled, or prescribed, burns are planned fires that happen under the watch of fire managers. Eric Knapp, a research ecologist for the Forest Service, told me such burns are “the most effective tool” for fire-hazard reduction.

These burns actually help the sequoias regenerate: Their tiny seeds struggle to open up unless they land on the bare soil left behind by a burn. So normal fire itself isn’t a problem. But climate change has led to bigger and hotter fires. Controlled burns preempt more destructive fire by clearing forests of too much fuel buildup—dead trees, fallen leaves, and other flammable material. “You can be proactive or you can wait for a wildfire to hit with really bad fuels and have a different outcome,” Knapp said. “And we all know we don’t like that outcome.”

Until recently, the park’s efforts focused on the grove itself. Dickman uses the analogy of a doughnut: “At the center of it is the Mariposa Grove, where we have got great fire history. But we haven’t done anything outside the grove.” In the past few years, Yosemite has begun fuel management along the roads connecting to the grove, manually removing about 9,000 tons of material. “Even though we think the grove is pretty well protected, we don’t want [a wildfire] to slam into it,” Dickman explained.

Because the Washburn fire started nearby, it didn’t have space to gather the ferocious momentum seen in some of California’s other recent fires before reaching the grove, according to Dickman. Luckily, when it did reach the grove, the fire hit the area of the most recent prescribed burn “and skirted around it,” before hitting a second former prescribed burn area, he explained. Firefighters were able to stand with “one foot” in these previously cleared areas and “steer the fire around the grove.” They were also able to “safely engage with the fire” from nearby Wawona Road, one of the park’s main thoroughfares, thanks in part to the fuel-reduction work done there.

The same principles used to protect the trees—controlled burns, manual clearing of fuel sources—are used to protect much less famous properties, particularly those communities that brush up against the wilderness. In 2021, California Governor Gavin Newsom signed a bill limiting liability for controlled burns in order to promote the practice, which Indigenous communities had long used—until settlers prevented them from doing so. (One prescribed burn in New Mexico did escape containment in May, though an official said that 99 percent go as planned.)

Californians living in high-risk fire zones are already required to consider fuel management within 100 feet of their home as part of defensible-space laws. That means clearing fallen leaves and branches and pinecones and other potential fuel, as well as spacing plants and trees far enough apart to protect them all from going up in flames. New regulations for Zone 0, which circles the first five feet of one’s home, are expected by January 1, 2023. (The California Department of Forestry and Fire Protection website notes that research has shown Zone 0 to be the most important of all the zones.)

Dickman told me he thinks about sequoia protection the same way. “If you create defensible space in and around giant sequoias, they’re going to fare so much better against fire,” Dickman told me. He said that, as we spoke, people were continuing to remove fuel from the grove—clearing the base of the sequoias and cutting down any snagged smaller trees, should the fire unexpectedly swing back.

With the planet’s temperatures continuing to warm, our parks, for all their emotional significance, will reflect the dangers that so much of the country faces. Yosemite isn’t the first park to experience climate-related weather woes this summer. In mid-June, once-in-a-lifetime flooding forced Yellowstone National Park to evacuate more than 10,000 tourists and shut down entirely.

Risk will also grow outside the parks, and we’ll have to put more effort into planning for disasters of a new scale. Living in a time of climate change will require understanding how to manage the fires we will have in order to protect what is protectable—and not everything will be.

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