Oak - Pine Forests
These forests occur at elevations of 5,500-7,500 feet. They are composed almost entirely of species with southern origins. Two pines, Chihuahuan pine (Pinus leiophylla var. chihuahuana) and Apache pine (P. engelmannii), and two evergreen oaks, silverleaf oak (Quercus hypoleucoides)and netleaf oak (Q. rugosa), predominate. These are forests of relatively short stature. The pines never form a closed canopy and are 40-80 feet tall, the oaks are 20-50 feet tall. These forests are found in almost all the Sky Island mountain ranges.
Bennett, P.S., M.R. Kunzmann and L.A. Graham. 2004. Descriptions of Arizona vegetation represented on the gap vegetation map. (PDF)