The Great Basin Bristlecone Pine, is a long-living species of tree found in the higher mountains of the southwest United States. The species is one of three closely related trees known as bristlecone pines and is sometimes known as the Intermountain or Western bristlecone pine.
A specimen of this species nicknamed “Methuselah” located in the Ancient Bristlecone Pine Forest of the White Mountains near Bishop, California is 4,842 years old (as of 2011), as measured by annual ring count on a small core taken with an increment borer. Its exact location is kept secret, since an older specimen, nicknamed “Prometheus”, was cut down in 1964. It is the oldest known tree in North America, and the oldest known individual tree in the world, although a clonal individual, nicknamed “Old Tjikko”, a Norway Spruce in Sweden is 9,550 years old.
Among the White Mountain specimens, the oldest trees are found on north-facing slopes, with an average of 2,000 years, as compared to the 1,000 year average on the southern slopes. The climate and the durability of their wood can preserve them long after death, with dead trees as old as 7,000 years persisting next to live ones.