Wayne D. Shepperd
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Aspen Ecology in the Western United States
Wayne D. Shepperd, Rocky Mountain Research Station, Ft. Collins, CO
Aspen, the most widely distributed tree species in North America is a vital component of almost every forest ecosystem in western North America, providing vegetation diversity, wildlife habitat, livestock forage, specialty forest products, and highly desirable scenery. Aspen’s ability to grow in full sunlight and vegetatively regenerate via root suckering allows it to thrive following fire, or other disturbance. Its unique clonal growth habit allows the expression of genetic characteristics on a large scale in western landscapes, either as stable aspen forests, or mixed with conifer species. Although aspen is susceptible to many diseases and damaging agents, it persists through periodic natural regeneration episodes driven by disturbance. Deteriorating aspen stands result when this natural cycle of renewal is interrupted, as has happened with wildfire suppression and excessive utilization of young aspen by browsing animals. The aspen regeneration triangle, representing the critical factors of hormonal stimulation, proper growth environment, and protection of new regeneration can serve as a useful guide in planning management actions in aspen forests.