With the caching of foxtail pine seeds by seed-eaters, seedlings often occur in dense clusters. Trees grow in open stands on dry sunny ridges. At higher elevations trees usually grow as widely spaced individuals in pure stands. Plants are intolerant of shade at all stages of growth. The growing conditions of ssp.
Temperature extremes are great and winds severe.
In both areas most of the precipitation occurs as winter snow. Foxtail pine is a climax species and persists at treeline for hundreds to thousands of years in the absence of disturbance and competition. Foxtail pines flower from July to August. The period of flowering and coneopening is uniform for foxtail pine, and the two bristlecone pines. Cones ripen from September to October with seed dispersal at this time.