Bear Grass, NPS photoKinnikinnick, NPS photoCedar-Hemlock Forest, NPS  Photo

As the meeting ground of four major floristic provences, the Crown of the Continent ecosystem supports a diverse array of plant species and plant communities. Here, the boreal forests of Canada meet up with Rocky Mountain (or Cordilleran) vegetation. The western-most extent of the Great Plains is found along the eastern edge of the Crown, and alpine vegetation is found at the highest elevations. Many species and plant communities reach the edge of their range here, including the eastern extent of cedar-hemlock forests and western larch, the northern extent for ponderosa pine, and the southern extent for numerous boreal and alpine species.

The diversity of vegetation types found in the CCE are largely a product of geology. As winds carry moist air from the Pacific Northwest, the air condenses and drops its moisture west of the Rocky Mountain barrier. The east side, not only sites in the range shadow of the Rockies, but is also subject to desiccating winds, resulting in more open forests and prairie grasslands. Local topography, water bodies, hydrology, and limestone rock outcrops all contribute to a range of microclimates and microhabitats that support a variety of vegetation types, which in turn provide food and shelter for wildlife. Periodic disturbances, such as wildfire, insect outbreaks, avalanches, and landslides, also affect vegetation patterns, and researchers are studying how climate change might impact disturbance cycles and vegetation communities.