Sudden oak death, caused by the invasive oomycete pathogen Phytophthora ramorum, continues to shape the dynamics of coastal populations of oak (Quercus spp.) and tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh) in California and tanoak in southwestern Oregon. Over the last decade, high mortality rates have been reported in natural populations of coast live oak (CLO; Quercus agrifolia Nee) in California, raising concerns for the integrity of important coastal ecosystems. However, it is now recognized that in spite of high infection and mortality rates, asymptomatic CLO have persisted.