A wildfire in Yosemite National Park is threatening some of the world’s oldest and largest trees, woodlands that have stood since before Rome was founded. The iconic Mariposa Grove of Giant Sequoias, which attracts a million visitors each year, has been closed while firefighters battle the Washburn Fire, which threatens to engulf it.

This 248-acre forest is home to more than 500 mature giant sequoia trees. Some of them are thought to be 3,000 to 3,500 years old. The magnificent Grizzly Giant stands 209 feet tall (more than 15 stories) and weighs an estimated 2 million pounds. Since President Abraham Lincoln signed legislation establishing the grove for public use in 1864, it has been protected.

The Washburn Fire, which started on July 7 and has burned 2,340 acres in Yosemite National Park, is dangerously close to the grove. According to the National Park Service, there were 545 people fighting the fire on Monday, and it was 25% contained. On Sunday, it was completely contained.

The fire is so powerful that the tremendous updraft created by its heat is sucking branches and other debris hundreds of feet into the air. They rain down on firefighters and planes fighting the fire as they fall.

On Saturday, the fire pulled a more than 2-foot-long tree branch several hundred feet into the air, narrowly missing two firefighting aircraft.

To protect the giant sequoias, the National Parks Service has dug fire lines and is using ground-based sprinkler systems to increase humidity in the area. Because the fire must expend more energy to burn, its intensity decreases, according to Craig Clements, director of the Wildfire Interdisciplinary Research Center at San José State University.

Giant sequoias can only be found in a few isolated areas along the West Coast. They are a relic species from before the Jurassic period.

“Continents have shifted, climates have changed multiple times, and these little pockets have survived,” Will Russell, a forest ecologist at San José State University, said. “Unfortunately, it appears that the current climate change pressure is affecting them in such a way that we may lose them.”

Given the high levels of logging over the last 150 years, only 80,000 giant sequoia are expected to survive. Those who remain are under threat from increasingly severe fires.

“We estimate that we lost 19 percent of all giant sequoia in the fire seasons of 2020 and 2021 alone, a 14-month period. It’s simply not sustainable “Joanna Nelson, Save the Redwoods League’s director of science and conservation, agreed.

Mariposa Grove is one of Yosemite’s three giant sequoia groves. Their massive trunks can grow to be nearly 30 feet in diameter, as large as a house. Some giant sequoias have branches as thick as regular tree trunks.

“These trees tower over us. They’ve been around for up to 3,400 years and provide us with context. They are natural temples “The Nature Conservancy’s senior forest ecologist, Ed Smith, agreed. “These groves have spiritual significance.”

Giant sequoias have evolved to live in a fire-prone environment, with enveloping, cork-like bark that can be up to 18 inches thick and insulates them from flames. Their deep roots protect them from the heat pulse of wildfires.

Prior to the focus on fire suppression, which began around 1900, these forests burned every 10 to 30 years on average. These small-scale fires cleared brush and needles but were of low intensity, allowing the sequoia to survive.

However, the accumulation of fuels now allows fires to burn hotter and higher. Furthermore, climate change has caused deeper droughts, drying out the land and making it more fire-prone.

“We’re dealing with species that have evolved over millennia, and we’re changing the rules of the game in a very short period of time and expecting them to adapt to the changes we’ve facilitated,” Smith explained. “It’s a little unrealistic.”

Temperatures are anticipated to warm into the 90s at Yosemite over Monday and Tuesday, which the National Parks Service says could mean increased fire activity. However, winds are predicted to be low.

“That should allow them to have pretty good containment soon,” said Clements.