The Mercury News Weekend

Researcher­s: Tree disease might be unstoppabl­e

‘Sudden oak death’ may be managed but not cured, study says

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DAVIS — An epidemic of the tree disease “sudden oak death” cannot be eradicated in California, but it can be managed, a new study shows.

The computer model used in the study published this week in the Proceeding­s of the National Academy of Sciences took into account topography, weather and factors like funds available to fight the extremely contagious disease. It has killed millions of trees along the Northern California coast since it emerged in 1995.

The study suggests that the disease is spreading too fast to root out statewide, saying it will accelerate after 2020 when it is likely to flourish in California’s northweste­rn corner, where conditions are perfect for it.

Had the state begun fighting the disease in 2002, it may have been possible to eliminate it, the study says.

Critics have faulted the state and federal government for failing to take such stronger actions, the Los Angeles Times reported.

But the report does not give a hopeless portrait, offering recommenda­tions for fighting the disease on a small scale to slow its growth by focusing on restoring small local forests.

“We’re going to have to learn to live with it and try to slow its spread with local management efforts and lots of experiment­ing,” UC Davis ecologist Richard C. Cobb told the newspaper. “We won’t be able to avoid much of the ecological impacts of losing all these trees ... but there is still time to avoid the worst possible outcomes of this epidemic by prioritizi­ng trees that are most at risk and taking steps to protect them.”

Up to 90 percent of California’s at-risk urban and wildland forests are still free of the disease, and the study intended to provide guidance on how to stop the next wave of its spread.

Cobb worked on the study with colleagues from North Carolina State University and the University of Cambridge in England.

 ?? RICHARD C. COBB VIAASSOCIA­TED PRESS ?? A horse grazes near a forest infected with the “sudden oak death” pathogen in Brookings, Oregon. A new study shows that an epidemic of the tree disease has spiraled out of control in California.
RICHARD C. COBB VIAASSOCIA­TED PRESS A horse grazes near a forest infected with the “sudden oak death” pathogen in Brookings, Oregon. A new study shows that an epidemic of the tree disease has spiraled out of control in California.

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