Petran Montane Conifer forests can be divided into mixed conifer and ponderosa pine forests. Merriam called the mixed conifer forests his Canadian Zone and the Ponderosa Pine forests his Transition Zone.
Mixed conifer forests are identified by dominance of Psuedotsuga menziesii and Pinus strobiformis. Aspen (Populus tremuloides) is a common tree in burned areas. Mixed conifer forest generally have well developed understories compared to spruce-fir forests. They are best developed above 8000 feet elevation. At lower elevations Pinus strobiformis is replaced with Abies concolor.
Pondersa Pine forests are characterized by Pinus ponderosa and the absence of other conifers. Other common trees include Quercus gambelii, with an understory of Ribes cereum, Rhus trilobata, Robinia neomexicana, and Ceanothus fendleri. Our ponderosa pine forests are best developed from 6500 to 8000 feet elevation and may look radically different based on past land use practices. They may be open-canopied with good understory and many different ages of pine or closed-canopied and comprised of a single age class. These later stands are sometimes referred to as "dog-hair" thickets.
visited in Mixed Conifer Forest: