Ponderosa Pine Mortality Resulting from a Mountain Pine Beetle Outbreak


Book Description

From 1965 to 1978, mountain pine beetles killed 25% of the pines taller than 4.5 feet in a study area in north-central Colorado. Average basal area was reduced from 92 to 58 square feet per acre. Mortality increased with tree diameter up to about 9 inches d.b.h. Larger trees appeared to be killed at random. Mortality was directly related to number of trees per acre and presence of dwarf mistletoe, but not to site index, elevation, and percent Douglas-fir in the stand.










Characteristics of Endemic-level Mountain Pine Beetle Populations in South-central Wyoming


Book Description

This study was conducted to evaluate the dynamics of endemic populations of mountain pine beetle (Dendroctonus ponderosae Hopkins). In addition, we extended the geographical range of an existing data base recorded in Utah with similar data from Wyoming. This work was accomplished in lodgepole pine (Pinus contorta Dougl. Var. latifolia Engelm.) stands on the Medicine Bow National Forest in south-central Wyoming. Thirty-eight variable-radius paired plots (BAF 10) were measured during the summer of 1987. Host-tree condition and mountain pine beetle infestation characteristics were determined from currently and previously infested trees. Presence and severity of Armillaria root disease and stem pathogens was determined. Tree condition and infestation patterns were similar at this site to those found in earlier studies. Trees selected by endemic mountain pine beetle populations were infested with Comandra blister rust (Cronartium Comandra PK) and root disease (Armillaria spp.). Host-tree condition and mountain pine beetle infestation patterns recorded in this study parallel those identified earlier in Utah and will help land managers identify trees to cut to reduce stand hazard to mountain pine beetle infestation.










Biology of Dwarf Mistletoes


Book Description