California’s giant sequoias can live for more than 3,000 years, their trunks stretching two car lengths in diameter, their branches reaching nearly 300 feet toward the clouds. But a few years ago, amid a record drought, scientists noticed something odd. A few of these arboreal behemoths inside Sequoia and Kings Canyon National Parks were dying in ways no one had ever documented—from the top down.

When researchers climbed into the canopies, they discovered that cedar bark beetles had bored into a few branches. By 2019, at least 38 of the trees had died—not a large number, but "concerning because we’ve never observed this before,” says Christy Brigham, the park’s chief of resource management.

Beetles have ravaged hundreds of millions of pines