"The fire blankets have been used for a long time to protect structures," Brigham said.
"We basically told the fire crews to treat all our special sequoias like they were buildings and wrap them all up, and rake all the litter away and roll away the heavy logs," Brigham told CNN.
It's not all about the aluminum
The shiny fire blankets have attracted a lot of attention, but they're not the only tool firefighters are using to protect the ancient sequoias.
Work crews have also been moving duff — decaying organic matter on the forest floor — away from the trees.
"We don't want that duff catching on fire and smoldering long term at the base of those trees," Wallace said, adding that it could "start cooking the roots."
"That's really what's going to hurt them," he added.
The extraordinary steps are being taken to protect the trees, Wallace added, because of the intense dry conditions in the forest.
Along with those measures, firefighting crews have been digging fire lines and conducting protective burns in some areas near trees, lodges and other structures in the park. Aircraft have also been able to fly over the area, dropping to help limit or put out flames.
Sprinklers were also used "pretty much nonstop" to protect the museum and other buildings near General Sherman, Wallace said on Sunday.
Access has also been key. In the area of the Giant Forest, firefighters were able to use walking paths to combat the nearing blaze. And with large trees falling across highways, timber cutters have been sent to clear roads and maintain vital access for firefighters.
Decades of controlled burns are now helping sequoias
"The fortunate thing is, the Park Service has done a lot of prescribed burning in there since the 1960s," Wallace said as he described the firefighters' task of protecting the Giant Forest.
"So it's making their job a lot easier," he said.
When flames ran through the brush and up a slope toward the forest, Wallace added, their height dropped from fearsome heights to a much more manageable 2 or 3 feet.
Sequoias can live for thousands of years — some of the specimens in the 68 groves along the Sierra Nevada's western flank have been alive for more than 3,200 years. These trees have lived through fires before, but officials are concerned by recent wildfires' frequency and intensity.
The Castle Fire in 2020 killed up to 14% of the large sequoias in the Sierra Nevada area, totaling up to 10,600 of the trees, according to early estimates. That accounts for about a third of the total area of their groves in the Sierra Nevada.
Experts are now working to identify which sequoia groves are overdue for a controlled burn and are most vulnerable to wildfires, through a project called the Giant Sequoia Lands Coalition. The group's members range from federal agencies to the University of California and the Tule River Indian Tribe.
Sequoias are "pioneer" trees that rely on fire to reproduce
Giant sequoia trees "need the unpredictable heat of fire to reproduce," according to the California Department of Parks and Recreation.
Before they can grow to heights of 300 feet or more, the department says, sequoia seeds must be released from cones — a process aided by fires, which dry and crack them open. Flames also help in other ways.
"Fire loosens the soil, allowing seeds to fall into the mineral-rich earth and gather moisture that was previously drawn by larger plants," the department says. In the process, fires also give sequoia seedlings a chance to establish themselves by clearing out duff and growth on the forest floor.
But for about 100 years — from the late 1800s through the late 1900s — fire became a rarity in sequoia forests, after the arrival of European settlers. That triggered "a massive failure of giant sequoia reproduction," the National Park Service said.
"Giant sequoias are a pioneer species — they are among the first to take root after a disturbance occurs," according to the National Park Service.