Identify Major Rocky Mountain Trees Using Forest Zones

A predominately spruce and fir forest is above the fir-aspen belt at approximately 9,500 feet to treeline. This region is the coldest, windiest and wettest belt - with maximum annual precipitation approaching 90 inches. Snow in this region can stay well into the summer months and the growing season lasts less than 120 days.
Vegetation, including trees, becomes smaller and show signs of environmental effects as you approach "treeline". You get trees that express themselves in miniature or are formed by the prevailing wind.
This zone is also called the Hudsonian zone because of the similarities with vegetation around Canada's Hudson Bay. Major tree species include subalpine fir, Engelmann spruce and blue spruce.
More on subalpine fir (pdf)...
More on Engelmann spruce...
More on blue spruce (pdf)...