Mountain pine beetle infestations developed to epidemic level in lodgepole pine stands on the Yaak District in 1972. Approximately 56,282 trees were killed from 1973 to 1975. By 1975, 2,068 ha were infested. This increased to 7,138 ha in 1976, representing a threefold increase. Current infestation occurs on 13 percent of the area risk rated high and given Priority 1 rating for management. Selective logging to remove infested and susceptible trees is in progress and it is recommended that these practices continue to reduce the infestation to endemic levels.