Great Basin bristlecone pine lives in the high and dry reaches of the White Mountains in eastern California, usually between 10,000 and 11,500 feet. It is closely related to the Rocky Mountain bristlecone pine (Pinus aristata), once considered to be the same species, and foxtail pine (Pinus balfouriana), which grows in the southern Sierra to the west. Some are over 4000 years old, and it is written that bristlecone pines can reach such great age because of (not in spite of) the very harsh, cold and dry, conditions, which may also limit the growth of pathogens.
Bristlecones always grow upright, unlike mountain hemlock and whitebark pine, which at timberline can produce a shrubby, low-growing form.
Needles are short, in fascicles of five, and can remain on the tree for 20 or 30 years, or more. Cones are about three inches long and have a sharp bristle on each scale.
Especially at harsh, high elevation sites, bristlecones do not reach great height, but sometimes attain great girth. At the Ancient Bristlecone Pine Forest, Inyo National Forest, California, the Patriarch, in Patriarch Grove, has a circumference of 38 feet, and was once supposed to be a cluster of separate trees that had grown together. However, more recent genetic analysis has shown that it is, in fact, one tree.
The forest is sparse at 11,000 feet, but the trees appear healthy, and there are many vigorous young trees.