Many accounts are incomplete although new information is being added continuously.
Errors do occur. Users are cautioned to refer back to the original cited source to assess completeness and correctness before using the information. Web updates are intermittent, not continuous, therefore some dynamic information such as legal status may not be absolutely current. The aspen type is the most common and extensive hardwood type in the western United States. It occurs primarily at middle elevations on a variety of sites in the Rocky Mountain cordillera, where it is usually succeeded by interior Douglas-fir.