A mountain pine beetle outbreak developed on the north face of Shook Mountain in 1972. Beetle populations increased, and have continued at an epidemic level since 1973. Surveys show 404,798 ponderosa pine containing 12,173,940 bd. ft. volume of merchantable timber; and 20,875 lodgepole pine containing 730,625 bd. ft. volume of merchantable timber were killed from 1974 through 1976. Losses will continue as long as stands remain overstocked and stagnated. Reducing basal area below 120 ft. /acre by thinning and removing infested trees will manage the infestation. Suggestions are given to prevent buildup of secondary bark beetles.