Ash from a wildfire is not the only thing raining down on Yosemite National Park’s giant sequoias right now. While the Washburn fire in California’s Sierra Nevada rages uncontained, park officials have turned on portable sprinklers to protect the grove of 500 giant sequoia trees, which according to CNBC “hold a unique place in American history.”
The grove and the Yosemite Valley were designated by President Abraham Lincoln in 1864 for “public use, resort and recreation,” the park service said. That was the first time a scenic area was designated by the government to be protected for the public’s enjoyment.
The National Park Service’s Yosemite unit said the fire, reported July 7 near the Washburn Trail in the Mariposa Grove section of Yosemite, had grown to more than 2,340 acres Monday morning. U.S. Forest Service officials warned it was likely to continue growing because of light winds and hot conditions.
More than 500 mature sequoias in the park’s Mariposa Grove are in danger and Wawona, a nearby community, has been evacuated.
Earlier reports that the trees had been wrapped in fire suppression foil weren’t true, park superintendent Cicely Muldooni told CNBC.
Efforts to save the trees included removing what could burn around the base of the trees and bringing in portable sprinklers “to change the humidity” around their trunks, as well, according to Jay C. Nichols, a spokesman for the interagency fire response team fighting the blaze in the park.
“The fire has entered the grove,” another fire response spokesman, Robbie Johnson, told CNN Sunday night. “But the good new is, because of prescribed burns and clearing out material on the ground, it’s clear in the Mariposa Grove,” where those battling the fire had created a “doughnut hole” of protection.
Teams also wrapped a beloved historic landmark, the Galen Clark cabin, in protective foil, CNN said. Clark reportedly convinced lawmakers and the president to protect the Mariposa Grove of sequoias back in 1857, leading to Lincoln’s designation.
Footage tweeted by Yosemite Fire and Aviation Management shows preparations to protect the Grizzly Giant, the best-known and second-largest giant sequoia in the grove, at 209 feet. That tree is believed to be close to 3,000 years old.
About the sequoia
The Save the Redwoods League says Sequoiadendron giganteum, the official name of the giant sequoia, is “the world’s most massive tree.” It notes that the tallest one known, located in the Redwood Mountain Grove, towers like a 31-story building. The biggest overall, in the Sequoia National Park, is 642 tons, roughly the weight of 107 elephants.
And the giant sequoia forest, located along the western slops of the Sierra Nevada, covers 48,000 acres, making it “the size of Cleveland.”
The group says the trees owe their size to their long lives and the speed at which they grow. But they also require a lot of water, which they absorb from the Sierra snowpack. They are too big for wind to blow over and fire has largely left them alone.
The National Park Service said that in fires, sequoias are often “insulated by their thick, spongy bark.” And their height sometimes allows their branches to avoid flames. But since about 2015, more intense fires have become “far more destructive” of giant sequoias, according to the National Park Service.
“We have reached a tipping point — lack of frequent fire in most groves, combined with the impacts of a warming climate — have made some wildfires much more deadly for sequoias,” the article said.
It notes that six fires between 2015 and 2021 killed many large sequoias in numerous groves in the Sierra Nevada range. “More than 85% of all giant sequoia grove acreage” across the range have burned in wildfires in that time, “compared to one one quarter in the preceding century.”
Surviving fire
In its incident update, the National Park Service reported that “fortunately, the Mariposa Grove has a long history of prescribed burning and studies have shown that these efforts reduce the impacts of high-severity unwanted fire.”
Officials said the smoke from the Washburn fire could reach San Francisco. Residents within reach of the smoke were being told to stay indoors if possible and keep their windows closed.
Meanwhile, SFGate reported a heat wave was developing in California Monday. And it said that “the Washburn fire on the western flank of the Sierra Nevada had scorched about 3.6 square miles by Monday morning, an increase of about 300 acres overnight, according to an incident update.”
While the park’s south entrance is closed, other areas of Yosemite remain open.
The New York Times reported that the firefighting effort included close to 12 helicopters and more than 360 firefighters. And it said that “fire activity is expected to continue over the next few days, when temperatures in the area could reach triple digits.”