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U.S. Forest Service

Bristlecone Pine - Limber Pine Forests

High elevation south-facing ridges in the Pinaleno Mountains. High elevation south-facing ridges in the Pinaleno Mountains often have open stands of bristlecone pine and limber pine. Photo by Charlie McDonald.

Trees on these exposed ridges. Trees on these exposed ridges are often stunted and wind-pruned. Dead snags are frequent in this harsh environment. Photo by Charlie McDonald.

These forests occur at or near 10,000 feet. The dominate trees, bristlecone pine (Pinus aristata) and limber pine (P. flexilis var. reflexa), come from the Rocky Mountains. In the northern Rocky Mountains, P. flexilis var. flexilis takes the place of P. flexilis var. reflexa that occurs in the Sky Islands and southward into Mexico. Variety reflexa is also very similar to southwestern white pine (P. strobiformis) that grows at somewhat lower elevations in the same mountain ranges causing considerable confusion identifying the two.

The branch tips of bristlecone pines. The branch tips of bristlecone pines have a characteristic “bottlebrush” shape. Photo by J.S. Peterson at plants.usda.gov.

Common juniper (Juniperus communis). Common juniper (Juniperus communis) is a low ground-hugging shrub in this and other high-elevation plant communities. Photo by J.S. Peterson at plants.usda.gov.

The trees in this plant community have conical crowns in protected habitats, but become wind-pruned “flagged” or even pressed flat to the ground in exposed habitats. Tree branches are flexible and do not break easily under heavy snow loads. Tree stands are open to very open (usually less than 20 percent overall vegetative cover) with scattered shrubs and grasses. These forests occur only in the Pinaleno Mountains on a few south-facing slopes and ridges.

Further Reading

Bennett, P.S., M.R. Kunzmann and L.A. Graham. 2004. Descriptions of Arizona vegetation represented on the gap vegetation map. (PDF)