Environmental Description:  This montane to subalpine riparian shrubland is found in the Colorado Rockies north to Montana, Idaho and Washington and may extend into Canada. This is a mountainous region with a varied, continental climate of warm summers and cold winters. Precipitation falls predominantly as snow in the winter and spring, although summer convective showers make a significant contribution to the total. It occurs in the lower subalpine zone, from 707 m (2320 feet) in the north to approximately 3110 m (10,200 feet) elevation in the southern extend, along moderate-sized streams in relatively broad glaciated valleys. The floodplains are low-gradient and have sand- or silt-beds within which the streams meander. It occasionally occurs on smaller streams with several 1- to 5-m wide channels. The sites often have active or abandoned beaver dams and ponds. Soils are usually well-developed but poorly drained, dark-colored silty clay loams. These soils often have much organic material intermixed and overlie deposits of gravel and rocks. Soils can occasionally be well-drained, gravelly loamy sand in habitats heavily influenced by fluvial processes (deposition and erosion).