Banff National Park is Canada's oldest national park, originally established in 1885 (thirteen years after the establishment of the world's first national park). This photograph illustrates two of the main ecoregions within the park, the nearly vegetation-free alpine and the lower-elevation subalpine.
In comparison with this photograph of a mountain in the park, the tree-line is not as well-defined. The rugged, rocky slope prevents both soil and seedling establishment in many places. It is also safe to say that periodic avalanches curtail the progression of forest cover on the slopes.