SACRAMENTO, Calif. — California's iconic trees, the giant sequoias, may sail through the state's current extreme drought. The huge trees survived even drier conditions during their long lives, studies show. The oldest sequoias live for more than 3,000 years.
But will giant sequoias still be around as California's climate shifts under the influence of global warming? It's hard to know — there are still too many unsolved mysteries about these massive trees, many scientists say. Even during California's last serious drought, in the 1970s, giant sequoias started growing faster, though no one is sure what is driving the gains. But climate models forecast even warmer and drier conditions by 2100 for California, which could make the sequoias' mountain soil too parched for the world's biggest trees. To better understand how to protect and preserve giant sequoias, scientists are looking at how sequoias live today, and where they lived in the past.
"We're particularly concerned about the giant sequoias, because they're really dependent on the snow melt in the Sierras," said Anthony Ambrose, a research scientist at the University of California, Berkeley (UCB). [Nature's Giants: Photos of the Tallest Trees on Earth]
Biggest straw on Earth
Since the 1950s, the Sierra Nevada snowpack has shrunk by nearly 15 percent. With less winter snow, which sequoias rely on for much of their summer water supply, both trees and their seedlings may suffer during long, dry summers. (The Sierra Nevada mountains are the only place in the world where sequoias are found.)
The President Tree, an enormous 3,240-year-old tree in Sequoia National Park, slurps 2,831 liters (748 gallons) of water every day during its growing season, according to research presented here at the Ecological Society of America's annual meeting Aug. 11 through Aug. 14. [All Yours: The 10 Least Visited National Parks (Photos)]
All that water supplies the mighty tree's huge amount of wood and almost 2 billion leaves. The leaves alone weigh in at just over 2 tons (1,831 kilograms), Ambrose said. "That's just mind-boggling," he said.
Ambrose and his colleagues climb sequoias and their cinnamon-colored cousins, the coast redwood, measuring how the trees change from bottom to top. The study is part of the 10-year Redwoods and Climate Change Initiative, funded by the Save the Redwoods League in San Francisco.
From their preliminary results, they found the leaves at the tops of these tall trees seem different than those at the bottom. (The tallest sequoias top out at more than 250 feet (76 meters), and some fallen trees are even longer.)