California's Sequoias Showing Signs Of Exhaustion Due To Drought

In August, a team of researchers visited the Sequoia National Park to access how the trees, among the largest and oldest in the world, were responding to the drought.

They noticed that the sequoias were showing visible signs of exhaustion, such as browning and fallen leaves.

"These trees, they live thousands of years," Anthony Ambrose, a tree biologist involved with the project, tells Here & Now's Jeremy Hobson. "They've undoubtedly dealt with pretty severe droughts in the past and other disturbances, such as fire. But the level of foliage die-back that is being observed this year and last year, has never been observed in the Park's 125 years history."

Ambrose says that while the giant sequoias are quite hardy, other trees in the park are not doing very well.

"Pines and firs and cedars, in particular in the Sierra Nevada, there are whole swaths, particularly at lower elevations, that are actually dying," Ambrose said. "The giant sequoias are tougher than these other species, so we are optimistic they'll be able to hang through this."