At 3 p.m. on August 17, 2013, a hunter’s illegal campfire crept out of control near Yosemite National Park. The fire spread through dry underbrush along Jawbone Ridge, licking up the trunks of ponderosa pines, searing and scorching until entire treetops burst into flames, flinging sparks and glowing needles skyward. On August 21 the fire, now known as Rim, went on a rampage, exploding over rocks and leaping the Tuolumne River, torching stands of centuries-old pines and plantations of young trees in a red-hot rage that blackened more than 125 square miles in just two days. By the time it was finally extinguished on October 25, the Rim fire had consumed 402 square miles of forest, an area 11 times the size of Manhattan.

Eight months later Ryan Burnett surveyed the scene from a crest overlooking the Tuolumne watershed. Ridgetop after ridgetop was covered with dead trees, some with needles scorched rust from the heat, others singed bare. Not a single green tree stood in the vast and bleak vista. And yet, a green patch of miner’s lettuce crept up a hillside; scarlet paintbrush poked out of the ashy gray dirt; a Lazuli Bunting zipped among the dead mountain mahogany; an American Kestrel hovered over burnt and brittle treetops—all astonishing, spectacular proof that fire creates even as it destroys.

Scientists have long known that fire is a primary force in shaping ecosystems. But because of its destructive power—incinerating homes, habitat, and valuable timber—frightened lawmakers and land managers have driven a campaign designed to control fire at all costs. Thus, for more than a century, fires were suppressed in California’s Sierra Nevada and throughout the West. And while this reduced historic levels of smoke and burned acreage, it left forest ecosystems critically out of balance. Without the cleansing fires that reduce ground fuels and kill some vegetation, many forests grew thick with trees and overcrowded with brush, a tinderbox that only made the landscape more vulnerable.

In those conditions, fire, naturally, has reasserted itself, and the number of wildfires in the West has grown by an average of about seven per year since the mid-1980s. At the same time, forests are burning both earlier and later in the season and with much greater severity than 100 years ago, a U.S. Forest Service study found. And a changing climate is predicted to bring further increases in the incidence of wildfire, say California experts. Temperatures in the Sierra are expected to rise an estimated 10 degrees Fahrenheit over the next century and the snowpack to melt almost a month earlier. That is, if there is snowpack. Last winter the Sierra was virtually snowless, dramatically compounding the effects of the state’s fourth year of drought. Researchers predict a combination of higher temperatures, increased evaporation, and reduced precipitation that could, in 70 years, more than double burned areas in California.