Now that scientists have figured out what causes "Sudden Oak Death," they're trying to get the word out on how to curtail the spread of the tree disease.
This magnified image shows the P. ramorum spores on the underside of a California bay laurel leaf.
In addition to prevention efforts, the California Oak Mortality Task Forces is also developing some best practices for dealing with those forests where large numbers of oaks are already dead or dying.
This photo shows diseased and tanoaks on Mount Tamalpias, one of the first areas where Sudden Oak Death appeared.
There's a map (pdf) showing areas of oak death in Northern California here.
Or link to the Sonoma County Sudden Oak Death Strategic Reponse Plan (83 pages, pdf) here .
Dr. David Rizzo, a leading Sudden Oak Death researcher at UC Davis, offers a summation of what is currently known about the disease, the pathogen that causes it, and how it is transmitted in a 30 minute video that can be seen here.