Pinus aristata

Rocky Mountain bristlecone pine is a member of the pine or Pinaceae family and is native mostly to the cold sub-alpine climates at high elevations (over 2,100 m) in Arizona, New Mexico and Colorado. It is a small tree reaching up to 6 m tall.

It is an attractive horticultural tree especially grown in colder climates in North America.

There are 3 closely related species of bristlecone pine:

• Great Basin bristlecone pine (P. longaeva)
• Rocky Mountain bristlecone pine (P. aristata)
• Foxtail pine (P. balfouriana)

• It is in the white pine subgenus (Strobus), needles are in bundles of 5, 2.5–5.0 cm long, curved, deep green, and only 1 band of stomata (resin canals) on the inner surfaces, resulting in highly characteristic white resin flecks appearing on the needles, unlike the 2 other bristlecone species. Needles are crowded and thick towards the ends of the branches. They can remain on the branches for 10–17 years.
• Branches generally are in yearly whorls.
• Seed cones take 2 years to mature and are ovoid-cylindrical, 5–10 cm long and 3–4 cm broad when closed, with numerous thin, fragile scales with bristle-like spines 4–8 mm long.
• Bark is thin, smooth, and gray-white on young trees, later becoming furrowed and reddish brown. Old trees on harsh sites may be highly weathered and have only a few strands of bark remaining in protected areas.