The grove of giant and ancient sequoia trees in California's Yosemite National Park is no longer under direct threat from the fire.
Residents of the mountain community of Wawona could return to their homes if the fire is contained.
It took more than the hard work of firefighters, luck, and a shift in the wind to protect the majestic trees in the Mariposa grove.
A half-century of intentional burning or ''prescribed fire'' practices in and around the area dramatically reduced forest ''fuel'' there, allowing the fire to pass through the grove with the trees unscathed.
The fire entered the grove and luckily we had 50 years of prescribed fire history there. In the early 1970s, the park started regular intentional burns. If we hadn't been preparing for this fire for a long time, it could have been a different outcome.
The other old-growth sequoia groves were not so lucky.
Native American tribes have been practicing fire practices to reduce fuels. Fire ecologists say that this ''good fire'' along with mechanical and other forest thinning practices are vital tools. Over a century-long policy that prioritized putting out most every fire, these intentional blazes reduce the amount of fuel loads.
Climate change is worsening the danger from built-up fuels, as it's driving more severe droughts and higher temperatures, and contributing to increasingly volatile weather.
The forest fuel is the cause of the fire. The fire ran into the area of the most recent prescribed fire and slowed its advance.
"After it hit that area, the fire intensity decreased dramatically, rate of spread decreased, and firefighters were able to quickly engage and start putting in hand line and hose lays and kind of steer the fire around the grove," Dickman says.
Fire crews removed smaller trees that could help spread the fire and set up sprinkler systems to protect the grove.
The "good fire" may have been the most important factor. Dickman compares a doughnut to a person. The doughnut hole is the location of the prescribed fire program for the past 40 years. The area on the outer edges of the doughnut has not burned in over 100 years.
The fire behavior in the doughy part of the "doughnut" was much more intense, fast-spreading and volatile.
He says that the flame lengths in the interior of theWashburn fire were hundreds of feet high. It was so hot that branches were thrown into the air and one almost hit a plane.
It takes a lot of heat to get branches into the air. There's 125 tons of fuel on fire and firefighters can't engage. It's too hot.
The sequoias are among the most fire resistant trees on the planet. They need to reproduce and survive fire. Today's fires are larger, burn hotter, and move faster because of a warming Earth and those fuel loads from the suppression of wildfire.
Dickman says that the fires of today are very different than the ones of the past.
The canopies of old-growth sequoias help protect them from fire. As heat opens their cones and spreads their seeds across the forest floor, they rely on wildfire to reproduce.
California's sequoias are under increasing threat due to the current high-severity fire. The state has been ravaged by a series of devastating wildfires since 2015, including the deadly Camp Fire. The giant sequoias have been killed off by fire in the last two years.
The power of consistent intentional fire is an example of how it can be used to protect a place.
Thousands of large sequoias were killed in the Castle Fire in the Sequoia National Forest in 2020 and in other fires in the state. Prescribed fires reduced forest fuel in some areas. Dickman says that the difference is in the areas where it wasn't done as frequently as in the Mariposa grove area.
There are groves in the Castle fire. It's not very easy to get in. He says it's hard to get fire on the ground.
If there's a silver lining from this fire, it's that federal, state and nongovernmental organizations are working more closely than ever sharing information, lessons learned and research tools and techniques on intentional fire and how to help reduce the threat of catastrophic wildfire.
We are all trying to do what we can to protect giant sequoias in the future.
The Forest Service stopped all prescribed fire in the US for 90 days after fires in New Mexico caused the largest wildfire in the state's history. Critics have called that nationwide pause a politically driven overreaction that also underscores how the agency's wildfire policies are out of sync with the reality of climate change. Ecologists want the forest service to scale and support its intentional fire program.
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