Program Aims to Prevent the Spread of Sudden Oak Death

On Saturday, July 14, 2018 a group of volunteers met at Portola Redwoods to kick off a pilot program for preventing the spread of Sudden Oak Death (SOD). The containment efforts will eventually include all the forested State Parks in the Santa Cruz District. This program will be coordinated with State Parks authorities and a UC Berkeley volunteer program that identifies areas of SOD infestation. Sometimes called “Ebola for trees,” SOD is a microscopic mold that has already killed as many at ten million trees in northern California. There is no cure for it, but there are ways to contain its spread. Anyone interested in helping with future SOD containment efforts please send an email to .


Pilot program volunteers, left to right:
Marshall Hicks, Steve Matthews, Jim McLaughlin, Margi McLaughlin, Debra Glusker


The SOD mold (P.ramorum) probably first came to the US from Southeast Asia before 1995 on nursery plants. Here in California SOD is fatal to four kinds of oaks, especially tanoaks. There are large numbers of tanoaks in the Santa Cruz District parks, and if unchecked SOD will kill them all. Large stands of trees that have been killed by SOD are now severe fire hazards and have contributed to the intensity of recent wildfires all over northern California. A healthy mature tanoak produces about a half-ton of acorns each year, while providing shade and habitat for many species, and its roots influence the chemistry of the soil. The loss of these trees would profoundly affect the ecosystems in our parks.

SOD is spread by its spores being transported through the air and in streams, but the biggest risk of spreading comes from humans. The spores easily hitchhike on vehicle tires, boots, shoes, tools and equipment. Future containment efforts will have to focus on human use of the parks as well as isolating or removing infected trees.

SOD has already been found near the entrance to Portola and we need to determine if it’s present in the park itself. If so, Parks will decide whether the infected trees should be removed. Bay trees are especially dangerous vectors of SOD because once they have the mold they produce lots of spores without being killed themselves. So the first step in the program is to map the location of bay trees in Portola, and later to determine if any of those trees are infected. In the future the volunteer group will work with park maintenance crews to establish practices that limit SOD spread, and to suggest ways for park visitors to help save our forests from this threat.

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