Fire crews struggling to save California giant sequoias

California - 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

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 U.S. 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 didn’t grow significantly 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 (1,487 cubic metres), according to the National Park Service. It towers 275 feet (84 metres) high and has a circumference of 103 feet (31 metres) 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,” 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 — fuelled by climate change — 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.

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.