Fire crews struggling to save California giant sequoias

Firefighters wrapped the base of the world’s largest tree in a fire-resistant blanket as they tried to save a famous grove of gigantic old-growth sequoias from wildfires burning in California’s rugged Sierra Nevada.

The colossal General Sherman Tree in Sequoia National Park’s Giant Forest, some other sequoias, the Giant Forest Museum and other buildings were wrapped for protection against the possibility of intense flames, fire spokeswoman Rebecca Paterson said.

The aluminium wrapping can withstand intensive heat for short periods.

Federal officials say they have been using the material for several years throughout the US West to protect sensitive structures from flames. Near Lake Tahoe, some homes that were wrapped in protective material survived a recent wildfire while others nearby were destroyed.

The Colony Fire, one of two burning in Sequoia National Park, was expected to reach the Giant Forest, a grove of 2,000 sequoias, at some point within days, fire officials said.

However, the fire did not grow significantly on Thursday as a layer of smoke reduced its spread in the morning, fire spokeswoman Katy Hooper said.

It comes after a wildfire killed thousands of sequoias, some as tall as high-rises and thousands of years old, in the region last year.

The General Sherman Tree is the largest in the world by volume, at 52,508 cubic feet, according to the National Park Service. It towers 275ft high and has a circumference of 103ft at ground level.

Sequoia and Kings Canyon national parks Superintendent Clay Jordan stressed the importance of protecting the massive trees from high-intensity fire during a briefing for firefighters.

A 50-year history of using prescribed burns — fires set on purpose to remove other types of trees and vegetation that would otherwise feed wildfires — in the parks’ sequoia groves was expected to help the giant trees survive by lessening the impact if flames reach them.

A “robust fire history of prescribed fire in that area is reason for optimism,” Ms Paterson said. “Hopefully, the Giant Forest will emerge from this unscathed.”

Giant sequoias are adapted to fire, which can help them thrive by releasing seeds from their cones and creating clearings that allow young sequoias to grow. But the extraordinary intensity of fires can overwhelm the trees.

That happened last year when the Castle Fire killed what studies estimate were 7,500 to 10,600 large sequoias, according to the National Park Service.

A historic drought and heat waves tied to climate change have made wildfires harder to fight in the American West.

Scientists say climate change has made the region much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.

A national interagency fire management team took command of efforts to fight the 11.5-square-mile Paradise Fire and the three-square-mile Colony Fire, which was closest to the grove.

Operations to burn away vegetation and other fuel that could feed the flames were done in that area.

The fires forced the evacuation of the park this week, and parts of the town of Three Rivers outside the main entrance remained evacuated.

To the south, a fire on the Tule River Indian Reservation and in Giant Sequoia National Monument grew significantly overnight to more than six square miles, and crews had no containment of it, a Sequoia National Forest statement said.

The Windy Fire, also started by lightning, has burned into part of the Peyrone Sequoia Grove in the national monument, and other groves were threatened.

“Due to inaccessible terrain, a preliminary assessment of the fire’s effects on giant sequoia trees within the grove will be difficult and may take days to complete,” the statement said.

The fire led the Tulare County Sheriff’s Office to warn the communities of Ponderosa, Quaking Aspen, Johnsondale and Camp Whitsett, a Boy Scouts camp, to be ready to evacuate if necessary.

The wildfires are among the latest in a long summer of blazes that have scorched nearly 3,550 square miles in California, destroying hundreds of homes.

Crews had limited ground access to the Colony Fire and the extreme steepness of the terrain around the Paradise Fire prevented it completely, requiring extensive aerial water and flame-retardant drops on both fires. The two fires were being managed collectively as the KNP Complex.