Foxtail Pines are closely related to Bristlecone Pines
The Foxtail pines and the Bristlecone pine populations are only 20 miles apart and are known to be able to crossbreed. This is treeline on the flanks of Mount Langley. In the background are the Inyo Mountains that have Bristlecone Pines at similar elevations. There are some Foxtail pines that have been measured to be over a thousand years old, and botanists think that they may reach three thousand.
These trees, like the Bristlecone live up high, at elevations of 9,000' to over 11,000' (as high as 3,400 meters) where the winters are severe and few other plants grow. They tend to grow on steep slopes with thin soil. It is believed that at these high altitudes, fungi does not thrive and so does not threaten the roots. The oldest trees are often found at the most rigorous sites.
There is an excellent reference book if you are interested.
"Conifers of California" by Ronald M. Lanner
You can find this book at many ranger stations in California.