Sudden Oak Death, SOD, which was discovered adjacent to district lands in 1995, is caused by the water mold, Phytophthora Ramorum. The disease has caused widespread dieback of Tanoak, as well as Coast Live Oak, Chinquapin, and Black Oak. Hundreds of plants are hosts, some of which can be killed by SOD, but on watershed lands only California Bay Laurel and Tanoak make more spores that spread the disease.
The loss of trees from SOD increases fire danger, creates canopy gaps in forests, reduces wildlife food sources, and increases the maintenance of roads, trails, and facilities as district staff deal with hazard and downed trees. MMWD recently mapped the progress of SOD through the landscape with funding assistance from the U.S. Forest Service.
If you are interested in learning more about SOD, its distribution, and treatment, you could explore the SOD blitzes offered throughout the Bay Area.