Bartos, Dale L; Amman, Gene D. 1989. Microclimate: an alternative to tree vigor as a 

 basis for mountain pine beetle infestations. Res. Pap. INT-400. Ogden, UT: U.S. Depart- 

 ment of Agriculture, Forest Service, Intermountain Research Station. 10 p. 



Thinning lodgepole pine stands increased light intensity, wind movement, insolation, and 

 temperature. Temperatures on the south exposure of tree trunks and of soil were signifi- 

 cantly higher in thinned than unthinned stands. Light and wind also were higher in the 

 thinned stand. Fewer mountain pine beetles were caught in pheromone-baited traps in a 

 thinned than in an adjacent unthinned stand. Percentage of trees killed by mountain pine 

 beetle was only 2 percent in a thinned stand compared to 16 percent in an adjacent un- 

 thinned stand. 



KEYWORDS: Pinus contorta, Dendroctonus ponderosae, pheromone, lodgepole pine 



