Yosemite’s growing Washburn Fire renews threat to sequoia trees

The Washburn Fire in central California has now scorched 4,700 acres from Yosemite National Park to Sierra National Forest as of Friday morning, officials said, growing over 300 acres overnight. The fire is renewing concerns about the impact of recurring wildfires on historic sequoia trees in the area.

According to park officials, the latest fire is 27% contained, with more than 1,500 firefighters assigned to it.

The persisting fire began near the Mariposa Grove of Giant Sequoias and now is claiming parts of Sierra National Forest, park officials said.

Since its first few days, when the fire measured 1,591 acres with 0% containment and 360 firefighters assigned to the fire, the threat to the area's famous sequoia trees remains a major concern.

As climate change effects worsen, such fires become an increasing threat to the durable, celebrated sequoia trees, and measures continue to be taken to protect the area.

Some of the tree trunks were wrapped in fire-resistant foil, a technique used in September to protect trees in Sequoia National Park's Giant Forest from fire.

A sprinkler system has also been set up within the grove to keep the sequoias’ trunks moist, officials said.

The trees, native to the Sierra Nevada range in California, are adaptive to fire, but intense ones could kill them, experts say. Wildfires sparked by lightning have killed about a fifth of the 75,000 large sequoias, the Associated Press reported last year.

The continued spread of the Washburn Fire has led to further road closures, including Forest Routes 5S43, 5S06 (Mt. Raymond Rd.), 5S22 and 5S37.

The closures are intended to assist firefighters in getting resources to and from the fire and to keep the public out of harm’s way, officials said.

The cause of the fire is still said to be under investigation. However, at a public meeting on Monday night, Yosemite's park superintendent said it appears to have been started by people.

The fire is expected to take weeks for it to be fully extinguished, as it is happening in “difficult terrain” due to heavy fuel lingering nearby after a significant tree mortality event from 2013 to 2015, according to Yosemite Fire and Aviation Management.

The fuel, consisting of both standing trees and those that have fallen to the ground, is presenting safety hazards to firefighters, officials said.

Further closures due to the fire include the Highway 41 entrance to Yosemite National Park, meaning that visitors will need to use Highway 120 or 140 to access the Yosemite Valley.

However, the remainder of the park remains open, despite heavy smoke on Sunday that affected air quality in the area and obstructed the park’s views.

The Tenaya Lodge, just south of Yosemite, remains open.

The community of Wawona and the Wawona Campground continue to be under a mandatory evacuation order, according to officials.

An evacuation shelter is available at the Mariposa New Life Church, located at 5089 Cole Road.