Garnet Fire spreads into McKinley Grove of ancient sequoias, Sierra National Forest, California

A lightning-sparked wildfire known as Garnet Fire entered the McKinley Grove of giant ancient sequoias in California’s Sierra National Forest on September 8, 2025. Firefighters reported ember ignition in upper branches but no complete canopy burn. Containment stands at about 15% after burning 22 000 ha (55 000 acres) since igniting on August 24.

The Garnet Fire, active in California’s Sierra National Forest since August 24, has burned more than 22 000 ha (55 000 acres) and remains 15% contained. On September 8, the blaze advanced into the McKinley Grove of giant sequoias, threatening some of the largest and oldest trees on Earth.

McKinley Grove spans approximately 40 ha (100 acres) and contains between 160 and more than 200 giant sequoias (Sequoiadendron giganteum), many estimated to be 2 000–3 000 years old and reaching over 70 m (230 feet) in height. Although embers ignited some canopy branches, no trees have been fully engulfed thus far.

Fire crews established 24-hour sprinkler systems, cleared surrounding vegetation, wrapped trunks with fire-resistant foil, and deployed smokejumpers and tree climbers to extinguish burning embers lodged in upper branches. Ground-level flames remained relatively low intensity, a condition that can promote cone opening and seed dispersal in giant sequoias.

Officials cautioned that despite this outcome, the grove remains at risk as nearly a century has passed since its last fire, allowing heavy fuel accumulation.

Prolonged drought and warming temperatures have also intensified wildfire behavior in the Sierra Nevada. Since 2020, an estimated 13–19% of mature giant sequoias in California have been lost to severe wildfires.

The Garnet Fire continues to affect regional air quality, with dense smoke prompting advisories in Yosemite Valley and nearby communities, reducing visibility and posing health risks.