The lightning-induced KNP Complex fire that began on September 9 has burned into 15 giant sequoia groves in Sequoia and Kings Canyon national parks, the head of resource management and science Christy Brigham told Bloomberg Green.
Two groves were torched by the high-intensity fire, which sent 100-foot flames up the tree trunks and had the ability to burn the canopies of the giant sequoias, which stand at an average of 300 feet tall.
Brigham warned that the trees, which could measure up to 20 feet in diameter and have lifespans in the thousands of years, could go up 'like a horrible Roman candle'.
South of the KNP Complex, the 152-acre Windy Fire has burned at least 74 sequoias, according to wildfire botanist Garrett Dickman.
He counted 29 sequoias in one grove that were 'just incinerated'.
'There were four of those that had burned so hot that they'd fallen over,' he added.
The California wildfires that have been charring the state for months may have killed hundreds of giant sequoias across the Sierra Nevada
Giant sequoias live thousands of years and grow an average of 300 feet tall and 20 feet in diameter
In the Giant Forest, which is home to about 2,000 giant sequoias, including the world's largest tree by volume the General Sherman Tree (pictured), firefighters are taking extra measures to protect the trees by wrapping fire-resistant material around the base of the trunks
As of Thursday, only 11 percent of 134 square miles of burning forest in the KNP Complex was contained. Cooler weather over the past week has helped slow the blaze and the forecast is for slight rain on Friday.
One grove of 5,000 towering trees had many engulfed in low- to medium-intensity fires, which sequoias have evolved to survive, Brigham told Bloomberg.
Wildfires that spread to the tops of trees - especially very tall trees - can move quickly through the forest,