Deadly oak virus creeping down mountains

Sudden OakDeath — the disease that has killed thousands of oaks in California in the last 12 years — is descending from San Mateo County’s highlands and into residents’ yards.

The disease, caused by a fungus called Phytophthora ramorum, was first discovered in 1995, and has killed thousands of oaks and infected dozens of other species since then. Some of those species, particularly the pervasive Bay Laurel trees, seem to be a major vector for the disease’s spread, according to Ronald Pummer, deputy agricultural commissioner for San Mateo County.

The virus is beginning to spread from open-space preserves to the backyards of residents in wooded areas such as Woodside and Portola Valley. The town of Woodside will host a public workshop on Sudden Oak Death and its prevention Aug. 2.

“It seems to be moving into lower elevations than we saw previously,” Pummer said. “We have some in Hillsborough, Portola Valley — it’s moving down the mountainsides.”

While Sudden Oak Death hasn’t been spotted in San Mateo County’s flatlands, it could eventually make its way downhill, “as long as there are Bay Laurels there,” Pummer said.

Woodside resident Virginia Dare recently inoculated the large, old oak trees in her yard after seeing oaks dying of Sudden Oak Death on Old La Honda Road, near her property. Trees not yet infected with the fungus can be vaccinated with a fungicide — a step she and her neighbors took to prevent the disease from killing their trees.

“When an oak is dying on your property, it’s like losing a family member, to be honest,” said Dare, who is a member of Woodside’s Open Space Committee. “They are really irreplaceable.”

Because towns such as Woodside and Portola Valley are so heavily wooded, they wanted to teach residents about the disease and what can be done to identify it, or even halt its spread, according to Teresa Dentino, a member of Woodside’s Conservation and Environmental Health Committee.

Woodside is already working with the California Oak Mortality Task Force, county open-space agencies and fire departments to study Sudden Oak Death’s spread in the community, according to Dentino.

“As a town, we wanted to be very proactive about this issue,” Dentino said. “The trees are a resource, in terms of ecology and wildlife habitat, as well as the aesthetic component and maintaining what we really treasure here.”

Woodside will host a Sudden Oak Death workshop on Aug. 2 at 7:30 p.m. at Woodside Town Hall, 2955 Woodside Road.

bwinegarner@examiner.com

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