Pinus balfouriana

Pinus balfouriana, the foxtail pine, is a rare high-elevation pine that is endemic to California, United States. It is closely related to the Great Basin and Rocky Mountain bristlecone pines, in the subsection Balfourianae. The two disjunct populations are found in the southern Klamath Mountains (subspecies balfouriana) and the southern Sierra Nevada (subspecies austrina). A small outlying population was reported in southern Oregon, but was proven to have been misidentified. P. balfouriana is a tree to 10–20 m (30–70 ft) tall, exceptionally 35 m (115 ft), with a trunk up to 2 m (7 ft) across. Its leaves are needle-like, in bundles of five (or sometimes four, in the southern Sierra) with a semi-persistent basal sheath, and 2–4 cm (1–1 1⁄2 in) long, deep glossy green on the outer face, and white on the inner faces; they persist for 10–15 years. The cones are 6–11 cm (2 1⁄2–4 1⁄2 in) long, dark purple ripening red-brown, with soft, flexible scales each with a 1-millimeter (1⁄16-inch) central prickle. P. balfouriana occurs in the subalpine forest at an elevation of 1,950–2,750 m (6,400–9,020 ft) in the Klamath Mountains, and at 2,300–3,500 m (7,500–11,500 ft) in the Sierra Nevada. In the Sierra Nevada, Foxtail pines are limited to the area around Sequoia and Kings Canyon National Parks. In both areas, it is often a tree line species. It is thought that P. balfouriana can live up to 3000 years in the Sierra Nevada, although the highest currently proven age is 2110 years. In the Klamath Mountains, ages are only known to about 1000 years. P. balfouriana is closely related to the bristlecone pines, being classified in the same subsection Balfourianae; it has been hybridised with the Great Basin Bristlecone Pine in cultivation, though no hybrids have ever been found in the wild.