In 1995, oak trees in Marin County started dying in unprecedented numbers.  Researchers started looking into this "Sudden Oak Death" and in their search discovered a new fungal organism, Phytophthora ramorum.  The name "Sudden Oak Death" or "SOD" for short became the moniker for this organism.  SOD is known to cause the sudden collapse of 3 major tree species, tanoaks, coast live oaks, and black oaks.  It was also found that this organism infects the leaves and small branches of a number of other plants.

Sudden Oak Death is known to occur in the hills near the Santa Cruz and San Mateo County borders.  To see a map of the positive finds in our County, click on the attachment below. 

For current information about Sudden Oak Death, visit the Oak Mortality Task Force's website.   

• California Oak Mortality Task Force
• U.C. IPM Website

• Map of Santa Clara County where Sudden Oak Death is known to occur