Spatial distribution of mountain pine beetle in the Morice Timber Supply Area in western British Columbia between 1995--2002

Mountain pine beetle (MPB, Dendroctonus ponderosae ) outbreaks are spreading at an unprecedented rate in British Columbia. To better understand which factors prevail in the spatial distribution of MPB, infestation data in the Morice Timber Supply Area (Western British Columbia) from 1995 to 2002 were analyzed using classification and regression trees (CART) modeling. The MPB occurrence in a given year was associated with between 2.5 and 5.5 beetle infested cells in a previous year (in 9 cells analysis window), elevation between 700 and 1000 m, stands where pine is a dominating or secondary species, stand age between 120 and 200 years, relatively warm falls, springs and winters, and high average annual precipitation. Despite many uncertainties stemming mainly from the quality of the data, the CART method proved to be useful in analyzing and explaining the hierarchical relationships between dependent and independent variables used this research.