Prescribed Burns Help Giant Sequoias Survive Wildfires, UC Davis Study Finds

Yet the modern era has brought a different kind of crisis. Decades of aggressive fire suppression, paired with severe droughts across the Sierra Nevada, left dense layers of dry brush, fallen logs, and dead trees carpeting the forest floor. When catastrophic blazes like the 2020 Castle Fire and the 2021 KNP Complex Fire ripped through the region, they did not behave like the low-intensity burns these ancient trees evolved alongside.

Instead, the flames burned with unprecedented fury. The two consecutive fire seasons destroyed roughly 19% of the world’s mature giant sequoia population across its native range, according to NASA science reporting. That sudden loss shocked forest managers and environmental scientists alike. Within Sequoia and Kings Canyon National Parks alone, high-severity fire zones incinerated hundreds of large trees, leaving behind blackened stags where thriving groves once stood.

University of California, Davis Researchers Measure the Survival Benefit

To understand what made some groves withstand the infernos while others collapsed, a team of researchers turned to advanced remote sensing technology. Utilizing airborne lidar—which uses laser pulses to map forest structure in three dimensions—alongside high-resolution PlanetScope satellite images, the scientists tracked pre-fire fuel loads and post-fire outcomes across approximately 26,400 individual giant sequoias in 19 distinct groves.

Published in Nature Communications, the study established that forest management practices made a measurable difference in survival rates. In practical terms, treated trees were nearly four times more likely to survive the Castle and KNP Complex fires than untreated neighbors in the exact same groves.

Computer simulations conducted by the research team indicated that past prescribed burns directly prevented about 1,900 sequoia deaths. Furthermore, the models suggested that if every mature tree across those 19 groves had received prescribed fire treatments beforehand, an estimated 3,900 additional sequoias would have survived the extreme weather.

The Long History and Complex Challenge of Controlled Burns in California

The protective power of fire is rooted in the biology of the trees themselves. Their elevated canopies keep living tissue safely above the reach of surface flames, and natural or cultural fires historically cleared out choking underbrush while opening up woody cones to release seeds onto mineral-rich soil.

Sequoia and Kings Canyon National Parks have maintained one of the nation’s most extensive prescribed fire programs since the 1960s, creating a patchwork of groves with varied fire histories. Yet scaling these operations across the broader Sierra Nevada remains fraught with administrative and environmental challenges.

Forest managers also face steep risks when attempting to apply controlled fire under volatile atmospheric conditions. In an autopsy of a 2022 prescribed burn in New Mexico’s Santa Fe National Forest that escaped its boundaries to become the largest fire in state history, U.S. Forest Service chief Randy Moore noted that drought, extreme weather, wind conditions, and unpredictable weather changes are continually challenging the agency’s ability to utilize prescribed fire as a reliable management strategy.

Coordinated Restoration Efforts Across the Sierra Nevada Range

Beyond thinning dense thickets and piling debris to burn outside of peak fire season, land managers have taken historic steps in forest regeneration. Park crews have planted more than 682,000 sequoia seedlings in severely burned areas. Because future climates are expected to pose severe hazards, forestry workers are intentionally sourcing seedlings from diverse groves to introduce genetic traits better equipped for a harsher environment.

Even with these intensive recovery operations on the ground, experts emphasize that vigilance must remain high as temperatures climb. So they make a lot. A lot, a lot, a lot.