write a very short paragraph on bristlecone pine.
A bristlecone pine can refer to one of three species of pine trees (family Pinaceae, genus Pinus, subsection Balfourianae). All three species are long-lived and highly resilient to harsh weather and bad soils. One of the three species, Pinus longaeva, is the longest-lived life form on Earth; the oldest individual is more than 5,000 years old, making it the oldest known individual of any species. Despite their potential age and low reproductive rate, bristlecone pines, particularly Pinus longaeva, are usually a first succession species, tending to occupy new open ground. They generally compete poorly in less-than-harsh environments, making them hard to cultivate. In gardens, they succumb quickly to root rot. They do very well, however, where most other plants cannot even grow, such as in rocky dolomitic soils in areas with virtually no rainfall. Bristlecone pine grow in scattered subalpine groves at high altitude in arid regions of the Western United States. The name comes from the prickles on the female cones. The green pine needles give the twisted branches a bottle-brush appearance. The needles of the tree surround the branch an extent of about one foot near the tip of the limb. The name bristlecone pine refers to the dark purple female cones that bear incurved prickles on their surface. The dark color of these cones help to absorb heat. After maturity, which takes about two years, the cones will become brown in color. These ancient trees have a gnarled and stunted appearance, especially those found at high altitudes, and have reddish-brown bark with deep fissures. As the tree ages, much of its vascular cambium layer may die. In very old specimens, often only a narrow strip of living tissue connects the roots to a handful of live branches. Even though the trees needles may age, they still remain functional in regulating water and by their ability to photosynthesize.