Mountain pine beetle dispersal: The spatial-temporal interaction of infestations

An understanding of mountain pine beetle (Dendroctonus ponderosae Hopkins) dispersal during an outbreak is important for modeling future infestations and aiding management decisions. Data on the spatial pattern of red and green attacked trees were used to characterize the spatial-temporal nature of dispersal. Research goals were to detect evidence of dispersal based on the distance and direction between red and green attacked tree clusters, determine how dispersal changes at different stages of infestation, and to detect landscape variables influencing the observed dispersal patterns. Key variables explored were Biogeoclimatic Ecosystem Classification (BEC), topography, and the local population of susceptible hosts. Dispersal distances of 30 meters and 50 meters were consistently observed among different data subsets. Findings suggest that short-range dispersal often occurs despite an available population of susceptible hosts, and as the infestation grows in intensity, the abundance of dispersing beetles causes spot infestations to coalesce.