Mountain Pine Beetle Influence on Lodgepole Pine Stand Structure

Abstract Efforts to control populations of mountain pine beetle (Dendroctonus ponderosae Hopk.) in lodgepole pine (Pinus contorta Dougl.) were evaluated from tree diameter distributions within treated and untreated stands. Beetle populations, where infestation period was complete, declined in approximately the same number of years, and lodgepole pine survival in the two types of stands was comparable. However, suppression measures did slow the rate of tree mortality in two stands still under attack. Mixed stands of up to 36 percent trees of other species were proportionally as susceptible to beetle infestation as those having less than 10 percent trees of other species. Survival increased with elevation, apparently because of adverse effect of temperature on beetles.