Colorado's 22 million acres of forested landscape are perhaps the most complex of any in the Intermountain West, with a diverse mix of coniferous and deciduous species. The most extensive forest types in Colorado are spruce-fir, ponderosa pine, lodgepole pine, aspen and piñon-juniper.

The basis for this vegetative mosaic is a physical landscape that ranges from flat plains and high plateaus to steep mountains, deep canyons and sloping foothills. A wide range of topographic, soil and growing conditions further influence this variety and contribute to the state's multi-faceted forest resources.

In addition to spruce-fir, ponderosa pine, lodgepole pine, aspen and piñon-juniper, forest types in Colorado include Douglas-fir, southwestern white pine, bristlecone pine, limber pine, Colorado blue spruce and the cottonwood-willow combination found in many riparian areas.