Mountain pine beetle reached epidemic levels in the Lap, Cool, Lang, and Caribou Creek drainages in 1974. From 1973 to 1975, approximately 56,282 trees with an estimated volume of 4,365,660 board feet were killed in these areas. An additional 61,721 trees are predicted to be killed in 1976. Currently infested acreage on the Yaak Ranger District equals 5,110 ac. (2,068 ha), This represents 5% of the 118,345 ac. (47,894 ha) risk rated high and given Priority 1 for management treatment. Selective logging to remove infested and susceptible trees is recommended to reduce the epidemic trend.