Fire crews in California have resorted to wrapping the bases of some giant sequoias in fire-resistant coverings in a desperate effort to save the towering specimens, including the General Sherman, the world's largest tree, the National Park Service said on Friday.

The blaze, one of dozens to erupt across several western states in a fire season that got off to an early start, forced the closing earlier this week of Sequoia National Park and left a dense layer of smoke in the area early on Friday.

The so-called KNP Complex fire, near the small town of Three Rivers, about midway between Los Angeles and San Francisco, grew to more than 11,000 acres (4,450 hectares) on Friday, according to the federal Inciweb fire information system.

It was burning about a mile (1.6 km) from Sequoia National Park's Giant Forest, home to the General Sherman, the largest tree on Earth by volume, park service spokesman Mark Garrett said.

Giant sequoias, many of which are more than 3,000 years old, grow only in the high elevations of the western slopes of California's Sierra Nevada mountains. With their thick bark, they can withstand most fires and even thrive on them.

Still, Garrett said, the park service was taking no chances with the General Sherman and a few of the other big trees.

“Even though they're fire-adapted ... we cannot lose that tree," Garrett said by phone.

The wraps are made of a fire-resistant, heat-reflecting material that firefighters carry for protection, he said.

The General Sherman tree towers over 2,000 other giant sequoias in the park at 275 feet (83 m) and is over 36 feet (11 m) in diameter at its base, according to the park service, about as high as the Capitol Dome in Washington, D.C., above its east front.

Crews of 482 firefighters, aided by aircraft, are battling the week-old blaze, which was started by lightning and is burning in difficult-to-reach steep canyons, fueled by dry timber and chaparral, the Inciweb system said.

Maximum wind gusts of about 40 miles per hour (65 kph) have been hampering firefighters, but a predicted cooling trend is expected to aid their battle, it said.

The KNP Complex is one of at least 28 fires in California and 129 across several western states that have erupted since June in a fire season that traditionally begins in late summer, according to Inciweb data.

Other steps the park service said it has taken to protect the sequoias are prescribed burns, which would reduce the amount of available fuel in case KNP complex reaches them.