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California’s blanket of coastal fog that rests on the redwoods’ canopy and fills the spaces between the giant trees is decreasing, a change that could affect the whole ecosystem, a new study reports.
"Fog prevents water loss from redwoods in summer, and is really important for both the tree and the forest," said University of California Berkeley biologist Todd Dawson in a statement, according to .
"The coast redwood is the tallest living tree species and notably long-lived, with some individuals exceeding 2,000 years in age. If the fog is gone, we might not have the redwood forests we do now," wrote Dawson and Berkeley’s James Johnstone, the authors of the paper, in the published in the Proceedings of the National Academy of Sciences.
One-fourth of the precipitation needed for the coastal redwoods to survive is obtained through fog, says the National Park Service's . Since the beginning of the 20th century, fog during the summers has decreased by about one-third, the authors found by looking at weather reports. The reason, they say, could be either natural ÃÛèÖAPP variations or human activities.
The fog is caused by warm temperatures from California’s interior meeting the cool Pacific Ocean waters. The cold air is trapped close to the earth’s surface and warmer air sits on top, an effect called an . (For more on redwoods, check out blogger Jason Chin's and picture book on the awe-inspiring trees.)
The redwoods without fog are like the Great Plains without thunderstorms. If the trend continues we may see less of what we’ve traditionally known as the redwood ecosystem, mainly the veil that helps make the giants so mysterious. What we will see, at least at first, is more of the forest—and the trees.