The leaves atop giant sequoias in the Sierra Nevada are better at storing water than those closer to the ground, an adaptation that may explain how their treetops are able to survive 300 feet in the air, researchers at American River College and Humboldt State University have found.

“It can take over a week for water to get from the ground to the top of the tree,” says Alana Chin, who led the study and is an instructor at American River College. “When you’re that tall of a tree, you’re under tremendous water stress.”