Landscape dynamics of aspen and conifer forests

Quaking aspen (Populus tremuloides Michx.) is widely dispersed across the l andscape of North America. Seventy-five percent of the aspen in the western United States occurs in the states of Colorado (50%) and Utah (25%). Repro duction in aspen is primarily by asexual means, e.g., rootsprouts that are generally referred to as suckers. An aspen clone consists of numerous stems that are genetically alike that began from a single seed that germinated s ometime in the past. Generally, these clones have been perpetuated on site by disturbance that allowed the clones to survive and expand in the area. T he importance of aspen in the Interior West is well described and documente d in the literature. Besides adding diversity to the landscape, aspen also provides water, forage, wood products, and so on for use by the public. Sin ce European settlement, the natural disturbance regime (usually fire) has b een interrupted. This has caused much of the aspen-dominated lands to succe ed to conifers. The decline in aspen ranges from 49% in Colorado to 95% in Arizona. Numerous techniques are available to aid the manager in restoring aspen to a level approaching its historical occurrence.