Montane Ponderosa Pine ForestPonderosa pine forests cover much of the higher country of Arizona from 6000 to about 8000 feet often forming essentially pure stands covering thousands of acres. Though this tree can be found in every state in the West, the largest continuous forest is here in Arizona, stretching from near Flagstaff along the Mogollon Rim southeastward to the White Mountains. Old growth ponderosa forests are characteristically open and park-like with large trees scattered about with grasses or shrubs beneath. C. Hart Merriam, an important early ecologist who studied the plant communities of northern Arizona, believed this forest to be transitional between the colder forests found farther north in Canada and the warm woodlands growing to the south in Mexico. Gambel oak is the most important associate of ponderosa pine in these forests. Other plant species include cliffrose, currant, and apache plume.
The beautiful, tassel-eared Abert's squirrel is a distinctive inhabitant of this forest. Few mammal species are so closely tied to a particular tree as this squirrel is to ponderosa pine. The bushy-tailed squirrel uses the tree for nesting, shelter, and food. The animal feeds on the ponderosa's seeds and the tree's cambium layer (the sugar-rich part of the tree just beneath the outer bark). Abert's squirrels can be quite acrobatic, chasing one another from tree to tree and sometimes jumping 40 feet or more to the ground apparently unharmed.
Mule deer and rocky mountain elk live among the pines in many areas of the state, while the white-tailed deer is an inhabitant of a mixed pine-evergreen oak woodland found in southeastern Arizona. The Mexican gray wolf once roamed these forests but was eliminated by the mid-1920s. However, it is being reintroduced into Arizona in the Blue Range Primitive Area along the New Mexico border and may once again roam the rugged high country in this part of the state.
Other smaller mammals inhabiting ponderosa pine forests include numerous chipmunks and voles. Several birds are commonly seen in this pine habitat, including the curious stellar jay, the tiny brown creeper, the pygmy nuthatch, several species of junco, and the colorful western tanager, a summer resident from the tropics.
Other Biotic Communities Biogeographic Regions