Phytophthora ramorum
Trials of silvicultural methods for treating "P. ramorum" began in Humboldt County in northwest coastal California in 2006. The trials have taken place on a variety of infested properties both private and public and have generally focused on varying levels and kinds of host removal. The largest () and most replicated trials have involved removal of tanoak and bay laurel by chainsaw throughout the infested stand, both with and without subsequent underburning designed to eliminate small seedlings and infested leaf litter. Other treatments included host removal in a modified “shaded fuelbreak” design in which all bay laurel is removed, but not all tanoaks; bay and tanoak removal using herbicides; and removal of bay laurel alone. The results of these treatments are still being monitored, but repeated sampling has so far detected only very small amounts of "P. ramorum" in the soil or on vegetation in the treated sites.
Arbutus menziesii
Increasing development pressures in its native habitat have also contributed to a decline in the number of mature specimens. This tree is extremely sensitive to alteration of the grade or drainage near the root crown. Until about 1970, this phenomenon was not widely recognized on the west coast; thereafter, many local governments have addressed this issue by stringent restrictions on grading and drainage alterations when "Arbutus menziesii" trees are present. The species is also affected to a small extent by sudden oak death, a disease caused by the water-mold "Phytophthora ramorum".