Trials of Mixed-Conifer Plantings for Increasing Diversity in the Lodgepole Pine Type

摘要

Greater forest diversity is needed in the lodgepole pine forest cover type--particularly, along and east of the Continental Divide in Montana--if large-scale losses from cyclical bark beetle outbreaks and subsequent wildfires are to be reduced. Three species were compared to lodgepole pine in a test of mixed-species planting in three ecological habitat types of the lodgepole pine type. Differences in seedling survival, condition, and growth were observed among species and among habitat types by the fifth year after planting. The results indicate Englemann spruce and Douglas-fir can be used to attain mixed-species stands by interplanting naturally regenerated lodgepole pine seedling stands. Western larch probably can succeed only when planted in moist Douglas-fir, spruce, or the warmer subalpine fir habitat types east of the Continental Divide. Because of greater frost tolerance, western larch x alpine larch hybrids are promising for increasing forest diversity in some of the colder subalpine fir habitat types.