Fuel and stand characteristics in ponderosa pine infested with mountain pine beetle, Ips spp., and southwestern dwarf mistletoe in Colorado's northern Front Range

Abstract

The effect of forest disturbances, such as bark beetles and dwarf mistletoes, on fuel dynamics is important for understanding forest dynamics and heterogeneity. Fuel loads and other fuel parameters were assessed in areas of ponderosa pine (Pinus ponderosa Laws.) infested with southwestern dwarf mistletoe (Arceuthobium vaginatum subsp. cryptopodum [Engelm.] Hawksworth & Weins), and in areas with endemic populations of mountain pine beetle (Dendroctonus ponderosae Hopkins) (Coleoptera: Curculionidae, Scolytinae) and Ips spp. in the northern Front Range of Colorado. One hundred fifty plots, each 0.04 ha, were permanently established throughout the summers of 2005 and 2006. The study area was composed of ponderosa pine, with Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) comprising a large portion of small diameter trees. Adjusted means for coarse fuel loads were greater in areas with relatively high densities (stems/ha or basal area) of mountain pine beetle- and Ips spp.-induced mortality that was greater than about 4 years post-tree death when compared to areas without bark beetle-induced mortality, adjusting for southwestern dwarf mistletoe infestation severity and stand and site characteristics. More recent bark beetle-induced mortality was not associated with differences in fuel loads. Areas with ponderosa pine infested with southwestern dwarf mistletoe were associated with different fuel arrangements and stand characteristics compared to areas with little to no infestation by southwestern dwarf mistletoe. Height to bottom of live crown was greater and percent live crown was less in plots with high severity of southwestern dwarf mistletoe infestation compared to plots without southwestern dwarf mistletoe-infested trees, adjusting for bark beetle-induced mortality. Together these biotic disturbances could have an affect on potential fire hazard by influencing the fuel amounts, fuel arrangements and stand densities.

Citation

Klutsch, Jennifer Gene. 2008. Fuel and stand characteristics in ponderosa pine infested with mountain pine beetle, Ips spp., and southwestern dwarf mistletoe in Colorado''s northern Front Range. Fort Collins, CO: Colorado State University. 147 p. Thesis.