photo: Matthew McDermott
A new study in the Proceedings of the National Academy of Sciences from scientists at the University of California, Berkeley shows how coastal fog in California has declined by about three hours per day over the past century, potentially endangering coast redwoods and the ecosystems they are part of. Since 1901, the average hours a day of fog has declined from 56% to 42% and the temperature difference between the coast and the interior has "declined substantially" the researchers say:This means that the coastal ecosystems may becoming increasingly stressed by drought. Report co-author Todd Dawson explains, "Fog prevents water loss from redwoods in summer, and is really important for both the tree and the forest. If the fog is gone, we might not have the redwood forests we do now."
Dawson went on to say,
As fog decreases, the mature redwoods along the coast are not likely to die outright, but there may be less recruitment of new trees. They will look elsewhere for water, high humidity and cooler temperatures.
Decreasing Temperature Gradient Linked to Less Fog
In determining the decline in fog and decrease in coast-inland temperature difference, the researchers analyzed data from 114 temperature stations from Seattle to San Diego. They found that the temperature contrast has declined along the entire coastline, but was most strong between stations in Ukiah and Berkeley, California where there is a 5°F lower temperature difference than there was a century ago. This decline is connected with decreases in average hours of fog per day.
The scientists say that it is unclear whether these changes are the result of natural cycles or because of human activity.
More on Climate Change in California
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California Drought Means Thousands of Trees to be Cut Down