Record fires killed nearly 1 in 5 mature giant sequoias, but controlled burns can boost survival
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A new study found that giant sequoias were nearly four times as likely to survive extreme wildfires in forests managed with prescribed burns, which decrease tree mortality. The work is published in the journal Nature Communications.
Giant sequoias are a unique species found naturally only on the western slopes of California's Sierra Nevada mountain range. These trees, which can reach more than 300 feet (91 meters) in height and more than 30 feet (9 meters) in diameter, are keystones of the ecosystem and serve as carbon sinks, water filters and structural habitats for birds, insects and small mammals.
Recent wildfires have caused far more giant sequoia deaths than usual, threatening the trees' future. Prescribed, or "controlled," burns help the trees by thinning underbrush, dead wood and other dry fuels, reducing the likelihood of mortality from high-intensity wildfires.
Tracking losses across 19 groves
Researchers analyzed data on 26,403 giant sequoias across 19 groves in Sequoia and Kings Canyon National Parks in the wake of the 2020 and 2021 fire seasons, when a record 6.8 million acres (2.8 million hectares) burned across California.
During those two years, 19% of the total mature giant sequoia population across the range was destroyed.
Remote sensing sharpens the case
The team combined lidar, stem maps, high-resolution imagery and modeling techniques to estimate giant sequoia mortality in relation to forest management practices. It found that prescribed burns saved roughly 1,800 giant sequoias.
While prescribed burns are widely considered among the best ways to protect giant sequoias, evidence to date has been primarily anecdotal. This study showed the value of high-resolution remote sensing for species-specific conservation efforts, with applications for old-growth forests worldwide.
Publication details
Dan J. Dixon et al, Previous prescribed burns saved thousands of ancient sequoias during historically unprecedented wildfires, Nature Communications (2026). DOI: 10.1038/s41467-026-75418-6
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Citation: Record fires killed nearly 1 in 5 mature giant sequoias, but controlled burns can boost survival (2026, July 21) retrieved 22 July 2026 from https://phys.org/news/2026-07-mature-giant-sequoias-boost-survival.html
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