SEQUOIA AND KINGS CANYON NATIONAL PARKS (CBS SF/AP) — A massive tree fell on four firefighters battling the KNP Complex Wildfire Thursday as the blaze continued to ravage the Sequoia groves located inside the Sequoia and Kings Canyon National Parks.

Fire officials said that at approximately 3:00 p.m. Thursday the base camp received a radio transmission that a tree had fallen, striking four individuals.

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“The patients were all brought to the nearest helispot and were transported by air to area hospitals,” officials said in a release. “All four individuals are receiving medical care. Thankfully, while the injuries are serious, they are in stable condition, and we are grateful.”

By Friday, the four — Cal Fire firefighter and three California Conservation Corps members — were released from the hospital.

The lightning-caused KNP Complex erupted on Sept. 9 and has burned into 15 giant sequoia groves in the park. More than 2,000 firefighters were battling the blazes in sometimes treacherous terrain.

KNP Complex Wildfires - Sequoias Killed

Flames burn up a tree in the Trail of 100 Giants grove in Sequoia National Forest, Sept. 19, 2021 (AP Photo/Noah Berger, File, File)

The KNP Complex was only 11% contained after burning 134 square miles of forest. Cooler weather has helped slow the flames and the area could see some slight rain on Friday, forecasters said.

The fire’s impact on giant sequoia groves was mixed. Most saw low- to medium-intensity fire behavior that the sequoias have evolved to survive, said Christy Brigham, head of resource management and science for Sequoia and Kings Canyon national parks.

“It’s heartbreaking,” she said.

However, it appeared that two groves — including one with 5,000 trees — were seared by high-intensity fire that can send up 100-foot flames capable of burning the canopies of the towering trees.

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That leaves the monarchs at risk of going up “like a horrible Roman candle,” Brigham said.

Two burned trees fell in Giant Forest, which is home to about 2,000 sequoias, including the General Sherman Tree, which is considered the world’s largest by volume. However, the most notable trees survived and Brigham said the grove appeared to be mostly intact.

General Sherman Tree Wrapped in Foil

The giant sequoia known as the General Sherman Tree with its base wrapped in a fire-resistant blanket to protect it from the intense heat of approaching wildfires at Sequoia National Forest in California. (Southern Area Blue Incident Management Team via AP)

Firefighters have taken extraordinary measures to protect the sequoias by wrapping fire-resistant material around the bases of some giants, raking and clearing vegetation around them, installing sprinklers and dousing some with water or fire retardant gel.

However, the full extent of the damage won’t be known for months, Brigham said. Firefighters are still occupied protecting trees, homes and lives or can’t safely reach steep, remote groves that lack roads or even trails, she said.

To the south, the Windy Fire had burned at least 74 sequoias, Garrett Dickman told the Los Angeles Times. The wildfire botanist has recorded damage as part of a sequoia task force preparing and assessing trees in the fire zone.

In one grove, Dickman counted 29 sequoias that were “just incinerated,” he told CNN.

“There were four of those that had burned so hot that they’d fallen over,” he said.

The 152-acre fire was 75% contained.

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