Accelerated forest dieback has been documented at many locations around the world that have experienced severe drought, warming and wildfires associated with global climate change. Exotic forest diseases pose a comparably large threat to wild forests. Synthesizing surveillance plot data to parameterize spatial epidemiological models, Cobb et al. (2020) estimate that the introduced invasive water mold, Phytophthora ramorum (Sudden Oak Death), has already killed 43 million trees in coastal evergreen forests of northern California and southern Oregon. Their results highlight the value of long term surveillance networks for monitoring and modeling the spread of invasive forest pathogens, and underscore the need for stronger public policy to reduce the global spread of these extremely harmful organisms.