Washburn Fire in Yosemite threatens sequoias in Mariposa Grove

A wildfire burning near the southern part of Yosemite National Park’s Mariposa Grove has become the latest blaze to threaten the world’s largest trees, which have been repeatedly imperiled in recent years as climate change increases the intensity of fires.

The grove, home to more than 500 mature giant sequoias, closed Thursday after visitors reported spotting smoke from the Washburn Fire near a trail. About 1,600 people — almost all tourists — evacuated the next day from the nearby community of Wawona, Calif., and its campground.

A wildfire in Yosemite National Park threatens over 500 sequoia trees. (Video: The Washington Post)

No injuries, destroyed structures or critical damage to the sequoias had been reported as of Saturday morning, said Nancy Phillipe, a spokeswoman for Yosemite fire information. All the named trees, including the 209-foot Grizzly Giant and the Bachelor and Three Graces, remained safe.

“That is one of the main priorities, is protecting that grove and all the history that’s associated with it,” Phillipe said.

Sequoia trees, which are native to only the Sierra Nevada and can live for about 3,000 years, have been increasingly endangered by worsening blazes in the past few summers. Although they’re used to frequent wildfires, three fires since 2020 have killed 13 to 19 percent of all sequoias. Natural resource experts expect that another large-scale die-off is possible this year.

The world’s largest trees are struggling to survive climate change

The Washburn Fire poses yet another threat. Its origin is under investigation, and Phillipe said there were no obvious weather-related causes.

Firefighters were using a variety of tools to protect the grove Saturday as the uncontained fire expanded to more than 700 acres, Phillipe said. Engines were spraying the sequoias with hoses and building hand lines, a type of fire line constructed with hand tools, to create fuel breaks. Crews were also covering sequoias in fireproof aluminum wrap.

From 2021: Fire threatens trees at Sequoia National Park. Fireproof blankets are the defense.

High temperatures and low humidity forecast for this weekend are set to complicate firefighting efforts, which already have been made difficult by numerous downed trees, Phillipe said. Trees destroyed by bark beetles, killed by climate-change-induced drought and felled by a major windstorm serve as fuel for flames.

Prescribed burns conducted periodically in Mariposa Grove in the past several years have helped slow the progress of unwanted fires, Phillipe said. In wildfire-prone areas, controlled burns get rid of fuel and clear space for firefighters to work.

Mariposa Grove, located near Yosemite’s south entrance, closed in 2015 and reopened three years later after a $40 million restoration project — the largest in the park’s history. The initiative restored sequoia habitat, realigned roads and added a shuttle service from the arrival area.

After all that work, Phillipe said, park employees are not giving up on protecting the grove.

“We’re suppressing this fire,” she said. “We’re doing everything we can to put it out.”

Last year, the trees in California’s Sequoia National Park were imperiled by the KNP Complex Fire when the lightning-sparked blaze came dangerously close to the 275-foot General Sherman, the largest tree in the world by volume. The Castle Fire in 2020 burned one-third of the region’s sequoia groves.

Nearly 23,000 acres have been scorched by wildfires in California this year.

People who never considered themselves at risk from climate change are waking up to floods and fires. (Video: Monica Rodman/The Washington Post)

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