Sudden oak death expands in San Francisco Bay Area

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An increased in sudden oak death in the Bay Area is believed to be caused by two years of high rainfall followed by the past dry winter.

An dramatic increase in sudden oak death incidence it believed to be tied to recent weather patterns.

Aerial and ground surveys have documented 375,700 new cases of dead live oak and tan oak trees over 54,400 acres of California where the pathogen that causes sudden oak death is known to exist, reported the San Francisco Chronicle. Last year there were 38,000 dead trees covering 8,000 acres.

Diseased trees were even found in Golden Gate Park, where there is no obvious source of the pathogen, such as nurseries or wildland.

"It's puzzling that we found it there because it's a totally urban environment, and I really didn't expect it. It shows how complicated and adaptable this organism is," said Matteo Garbelotto, UC Cooperative Extension specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. "The area doesn't have a lot of oaks, so I'm not worried about oaks there, but I'm worried about other plants being infected and, of course, people carrying it on their shoes."

Garbelotto's lab is mapping the spread of the pathogen that causes sudden oak death by plotting the test results from thousands of bay laurels and other hosts taken by citizen volunteers. SODMAP is updated every year to help cities, counties and homeowners protect endangered oak trees.

Posted on Wednesday, October 10, 2012 at 2:33 PM

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