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.