Northern California’s wildfires may have killed hundreds of giant sequoia trees as the blazes swept through groves in the Sierra Nevada, officials said.
The lightning-sparked KNP Complex fire that erupted on September 9 has burned into 15 giant sequoia groves, according to Christy Brigham, head of resource management and science for Sequoia and Kings Canyon national parks.
More than 2,000 firefighters are battling the blaze in sometimes treacherous terrain.
On Wednesday afternoon, four people working on the fire were injured when a tree fell on them, the National Park Service reported.
They were airlifted to hospitals and “while the injuries are serious, they are in stable condition”, the report said.
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 light rain on Friday, forecasters said.
The fire’s impact on giant sequoia groves was mixed. Most saw low- to medium-intensity fire behaviour that the sequoias have evolved to survive, Ms Brigham said.
However, it appears that two groves – including one with 5,000 trees – were seared by high-intensity fire that can send up 100ft flames capable of burning the canopies of the towering trees.
That leaves the monarchs at risk of going up “like a horrible Roman candle”, Ms 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.
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However, the most notable trees survived and Ms Brigham said the grove appeared to be mostly intact.
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 will not be known for months, Ms 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, Mr 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 is estimated to be 75% contained.
Giant sequoias grow naturally only in the Sierra Nevada.
The world’s most massive trees, they can soar to more than 250ft, with trunks 20ft in diameter, and live for thousands of years.
The trees need low-intensity fire to reproduce. Flames thin out the forest of competitors such as cedars, clearing away shade, and the heat causes the seedlings to open. But fire officials say recent blazes have been much more intense because fire suppression efforts left more undergrowth that has turned bone dry from drought, driven by climate change.
Last year’s Castle Fire in and around Sequoia National Park is estimated to have killed as many as 10,600 giant sequoias, or 10% to 14% of the entire population.
While some groves may have received only patchy fire damage and will recover, every burned giant sequoia is a loss, Ms Brigham said.
“When you stand by a tree that big and that old, 1,000 to 2,000 years old, the loss of any is a heartbreak,” she said.
“You can’t get it back, it’s irreplaceable.”
California fires have burned more than 3,000 square miles so far in 2021, destroying more than 3,000 homes, commercial properties and other structures.
Hotter and drier weather coupled with decades of fire suppression have contributed to an increase in the number of acres burned by wildfires, scientists say.
And the problem is exacerbated by a more than 20-year western megadrought that studies have linked to human-caused climate change.
