In general the forest of the Rocky Mountains has different kinds of trees that are dominant at different elevations. These dominant trees make up different forest zones in the Rocky Mountains.
The dominant trees in the forests of the Rocky Mountains change depending on elevation, latitude, and aspect or exposure. All of these strongly influence the climate of a location. In other words these will influence how warm or cold a location is, how much water is in the soil, how much snow it gets and how long the winter will be. These factors strongly influence what kinds of plants and trees can survive in an area.
Some of the common trees of the Rocky Mountains include Aspen, Rocky Mountain Maple, Pinyon Pine, Ponderosa Pine, and Engelmann’s Spruce.
The higher in elevation you go up in the mountains the climate becomes colder and harsher. This impacts what kinds of trees can survive in those areas and changes the forest.
Latitude impacts the forest in the same way that elevation does. The further north you travel the climate becomes colder and harsher. This means that the dominant trees in Southern Colorado at 8,000 feet elevation may be similar to the dominant trees in Montana at a much lower elevation because Montana is much further north than Southern Colorado. Traveling north impacts the forest in the same way that traveling up in elevation does.
Exposure or aspect is simply what direction a slope or spot on the mountain is facing. Areas on south – facing slopes will get much more direct sunlight than north-facing slopes. This has a very strong influence on what can live there. If you look at a mountain you can see the impact of exposure by comparing the vegetation of two slopes at the same elevation with different aspects.
General Forest Zones of the Rocky Mountains
Keeping in mind these three main factors the forests of the Rocky Mountains generally are dominated by certain kinds of trees at different elevations. The lower elevations are dryer than the higher elevations and typically have trees that are better adapted to living in dry conditions. The higher the elevation, the slower the tree will grow. Here are the main forest zones of the Rocky Mountains:
Spruce-Fir – Engelmann’s spruce, subalpine fir, and Colorado blue spruce
Fir-Aspen – Douglas fir, aspen, and lodgepole pine
Pine–Oak – Ponderosa pine, Gambel oak, willow, and maple
Pinyon–Juniper – Pinyon pine, juniper, cottonwood, and box elder
For more information on any of these trees, click here for common trees of the Rocky Mountains.