The highest elevations in the forest are located in the San Francisco Peaks area north of Flagstaff. Here grow large conifers such as Engelmann spruce, blue spruce, subalpine fir, corkbark fir (a variety of subalpine fir found only in isolated areas of Arizona and New Mexico), Douglas-fir, bristlecone pine, and limber pine. Isolated stands of quaking aspen, usually the first tree to regenerate following a severe wildfire, are scattered across the mountain.