From giant Sequoias in the east to wind-swept Monterey cypresses
in the west, California is defined by its trees, so a surge this
year in oak deaths is cause for consternation across the Bay
Area. A recently completed survey shows 376,000 dead oak trees
across the coastal regions impacted by sudden oak death, a
pathogen that develops on host plants ranging from the bay
laurel to ornamental rhododendrons. Last year’s survey, like
this one aided by volunteers led by scientists at UC Berkeley
and the California Oak Mortality Task Force, found 38,000 dead
trees across a much smaller area. “It’s huge. It’s really huge,
but it’s not the largest die-off we’ve had,” said Katie Palmieri
of the task force. That came in 2007 after extremely wet springs
the previous two years left 830,000 trees dead. The fewest
number of dead trees were counted in 2010, when 2,700 trees died
after a dry spring in 2009. In the current survey, the highest
rates of new infection in oaks and the beech-family member
tanoak were discovered in