Giant sequoias only grow naturally in California today. But they once ranged as far east as Colorado, Wyoming and Nevada, before the climate turned drier and pushed them into their current, narrower range. Now, even that shrunken sequoia forest is under threat. Wildfires have killed off nearly one-fifth of all large sequoias across their native range over the last decade; a steep loss for a species that can live for thousands of years. A new study … finds those losses aren’t inevitable. Researchers at the University of Nevada, Reno studied Mountain Home Demonstration State Forest, home to the world’s largest old-growth sequoia grove, after the 2020 Castle Fire. Some parts of the forest had been thinned or deliberately burned in the 15 years before the fire, while others hadn’t. The difference was stark. Sequoias in untreated forest died at more than double the rate of those in treated areas, said Bryant Nagelson, the study’s lead author.