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Bristlecone pines
A Great Basin Bristlecone Pine forest
Scientific classification
Kingdom: Plantae Division: Pinophyta Class: Pinopsida Order: Pinales Family: Pinaceae Genus: Pinus Subgenus: Ducampopinus Section: Balfourianae
Species
Pinus aristata Pinus longaeva Pinus balfouriana

The bristlecone pines are a small group of pine trees (Family Pinaceae, genus Pinus, subsection Balfourianae) that can reach an age far greater than that of any other single living organism known, up to nearly 5,000 years.

There are three closely related species of bristlecone pine:

• Rocky Mountains Bristlecone Pine Pinus aristata in Colorado, New Mexico and Arizona
• Great Basin Bristlecone Pine Pinus longaeva in Utah, Nevada and eastern California
• Foxtail Pine Pinus balfouriana in California

This one might have died hundreds of years ago, but still stands. Its wood gives clues to scientists who read the rings to compare to rings of living trees, making a 10,000 year-long record.

Currently, the oldest living organism known is an individual of Pinus longaeva nicknamed "Methuselah" (after Methuselah, the longest-lived person in the Bible), located in the Ancient Bristlecone Pine Forest in the White Mountains of eastern California, and measured by core samples to be about 4,700 years old. The U.S. Forest Service does not reveal the actual position of "Methuselah" in the bristlecone grove, in order to protect the tree. A bristlecone older than "Methuselah", named "Prometheus", was cut down in 1964. The other two species are also long-lived, though not to the extreme extent of P. longaeva; specimens of both have been measured or estimated to be up to 3,000 years old.

Bristlecone pines grow in isolated groves at and just below tree-line. Because of cold temperatures, dry soils, high winds, and short growing seasons, the trees grow very slowly. The wood is very dense and resinous, and thus resistant to invasion by insects, fungi, and other potential pests. As the tree ages, much of its bark may die; in very old specimens often leaving only a narrow strip of living tissue to connect the roots to the handful of live branches.

Gnarled bristlecone pine wood

The oldest single living organisms known are bristlecone pines, though some plants such as creosote bush or aspen, form clonal colonies that may be many times older. The existing growth in clonal colonies sprang as shoots from older growth so there is an unbroken chain of life that sometimes dates back several tens of thousands of years. However, the original ancient growth in these colonies is long dead. The oldest bristlecone pines are single plants that have been alive for about 5,000 years. These very old trees are of great importance in dendrochronology or tree-ring dating.

• Bailey, D. K. 1970. Phytogeography and taxonomy of Pinus subsection Balfourianae. Ann. Missouri Bot. Gard. 57: 210-249.
• Richardson, D. M. (ed.). 1998. Ecology and Biogeography of Pinus. Cambridge University Press, Cambridge. 530 p. ISBN 0-521-55176-5.
• ARKive - images and movies of the bristlecone pine (Pinus longaeva)
• Bristlecone pine website
• Arboretum de Villardebelle Images of cones (scroll to bottom of page)
• Gymnosperm Database - Pinus aristata
• Gymnosperm Database - Pinus longaeva
• Gymnosperm Database - Pinus balfouriana
• Companion web site for Nova episode about the Methuselah Tree
• Prometheus: The Martyred One
• NOVA Online: Methuselah Tree (PBS television program, originally broadcast on December 11, 2001)