Sudden oak death isn’t really all that sudden, but it is caused by the pathogen Phytophthora ramorum, which lives and moves in water. It has over 50 different host plants that carry it that ultimately transmit it to oak trees. The most common true oak that’s affected by it are live oaks, white oaks, and tan oaks. We cannot reverse the effects of a tree once it’s been infected. We can prolong the life through treatment, and if the tree does not have the pathogen, we can prevent it from getting it by doing treatments.
We use a combination of a product called Agri-Fos, which is just basically a salt fertilizer, and a penetrant, Penta-Bark, which allows the tree to be able to absorb the material into its system and spread it throughout the tree. Typically we spray the bark the first 10-12 feet around the base of the tree, but we also have the ability to inject the tree with phosphite, which is the active ingredient in Agri-Fos, so there’s no spraying involved whenever we do that.
It is important to note that we’re still under an oak wood quarantine in Marin, so you can’t cut wood and move wood around.