Researchers in a NASA-funded study calculated that prescribed burns made giant sequoias almost four times as likely to survive extreme fires. They examined 26,403 trees across 19 groves after the 2020 and 2021 California fire seasons. During those years, fires destroyed 19 percent of the mature giant sequoias across the species' range. The analysis combined lidar, stem maps, high-resolution imagery and modelling to compare mortality under different forest-management histories.
Prescribed burns remove underbrush, dead wood and other dry fuels before an uncontrolled fire arrives. This lowers the chance that flames reach intensities that kill old trees. The study estimates such treatment saved roughly 1,800 giant sequoias and provided firmer evidence than earlier anecdotal observations. Giant sequoias grow naturally only on the western slopes of California's Sierra Nevada and can live for more than 3,000 years. They store carbon, filter water and provide habitat, so protecting them also supports wider forest ecosystems.