Decrease in fog threatens California's sequoias: study

Decrease in fog threatens California's sequoias: study

1 hr 54 mins ago

WASHINGTON (AFP) – California's coastal fog has decreased significantly over the past 100 years, potentially endangering coast redwood trees dependent on cool, humid summers, according to a new study made public Monday.

The study by University of California, Berkeley, scientists said it was unclear whether this phenomenon was part of a natural cycle or the result of human activity.

But it warned the change could affect not only the redwoods, but the entire redwood ecosystem.

"Since 1901, the average number of hours of fog along the coast in summer has dropped from 56 percent to 42 percent, which is a loss of about three hours per day," said study leader James Johnstone, who worked at the University of California's Department of Geography before becoming a post-doctoral scholar in the campus's Department of Environmental Science, Policy and Management.

"A cool coast and warm interior is one of the defining characteristics of California's coastal climate, but the temperature difference between the coast and interior has declined substantially in the last century, in step with the decline in summer fog," Johnstone continued.

more...
http://news.yahoo.com/s/afp/usenvironmentclimatecaliforniaforest


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Around the Redwoods, the Fog Is Dissipating
By HENRY FOUNTAIN
Published: February 15, 2010

Fog may come on little cat feet and sit on silent haunches before moving on, as the poet Carl Sandburg wrote, but in central and Northern California it plops its bulk down on the state’s redwoods and makes itself quite comfortable.

Frequent summer fog along the coast from Monterey to the Oregon border helps nurture the coast, or California, redwood (Sequoia sempervirens), which inhabits a narrow north-south band in that region.

The fog, however, is less frequent than it used to be, according to a study by James A. Johnstone and Todd E. Dawson of the University of California at Berkeley. And that may be stressing the tall trees, they write in The Proceedings of the National Academy of Sciences.

Coastal fog in California is produced by a combination of factors, including upwelling of cool ocean water and atmospheric inversions that trap humid air at low altitudes. To obtain a historical record of coastal fog, the researchers looked at data on ceiling heights recorded hourly at several airports from 1951 to 2008. And they extrapolated back to 1901 using long-term land temperature data.

Their central finding is that since the early 20th century, fog frequency in summers has declined by about one-third.

more...
http://www.nytimes.com/2010/02/16/science/16obfog.html?partner=rss&emc=rss




Coastal fog near California's redwood trees has been on the decline.

The coast redwoods and the sequoias are different species.

One lives on the coast, one lives in the Sierra. The picture is of the Sierra species.

we can protect our precious Sequoias.