Bristlecone Pines

The grotesque, beautiful bristlecone pines are the oldest living things on earth.

Wilderness Exhibit

By Tom Jenkins

Researched by Marty Vyn Boennighausen

In the summer of 1964, Donald Currey arrived at the Humboldt National Forest in Nevada. A geology student, he was studying the dates of glacial features by "coring"trees, or extracting a thin strip from the wood to count the rings. He was in the process of coring a tree when the tool he was using broke. He got permission from a Forest Service supervisor to chain-saw the tree. After sectioning the tree at eight feet above the base, he counted the rings: 4,844. He had destroyed the oldest living tree on earth.

Currey's discovery had grown at an altitude of 11,400 feet within a ruck of quartzite boulders fourteen miles from the Utah-Nevada border on Wheeler Peak. The tree was seventeen feet high, 262 inches in circumference. It had been there for almost 4,900 years.

The bristlecone is peculiar to the Western United States. Among the fifty-four sites in Colorado where these trees are found, none are more spectacular and accessible than those at Windy Ridge south of Breckenridge and a the Mount Goliath Natural Area on Mount Evans. Although other trees (including limber pine, Engelmann spruce, and one-seed juniper) living at or near timberline develop similar traits of "wind timber," few become as old, as convoluted, or as fascinating as the bristlecone pine.

Its genetic patterns make the tree a paradox. Slow to grow and slow to die, the adjustment of the bristlecone to its adverse environment of ravaging wind, limited moisture, eroded soil, sparse foliage, and short growing season is near miraculous. The irony is that this foreboding environment is what keeps the trees alive. The bristlecone persists throughout centuries of successive stages of dying until a tree becomes 90 percent dead - yet still produces seeds. It is precisely because of this adaptive process that the bristlecone is the oldest living organism on earth.

Of the many factors that contribute to the adaptive, slow growth rate of the bristlecone, perhaps the most important one is the unceasing wind. Its force restricts the growth of foliage, reducing the amount of tissue the tree must sustain. Although the windward side of the tree usually dies, a narrow strip of bark on its leeward side nourishes it. Its needles, over the centuries, have become progressively smaller and increasingly waxy to minimize the loss of moisture. The resulting slow growth rate produces a hard, resinous wood, almost impervious to disease.

Misshapen by wind and time, in some cases bent almost to the ground, often with its roots torn from the protective rocky soil, the bristlecone pine survives, its huge coiling tentacles reaching to the core of memory. A few have been growing since the birth of Christ. The trees resemble mythic creatures, Halloween apparitions, dancing scarecrows. A few are completely dead from the punishing elements yet remain standing or leaning in skeletal silence. Twisted into asymmetrical shapes, they are both grotesque and beautiful.

To today's scientists of dendrochronology (the science of dating events by examining the growth rings of living trees and dead wood), these aesthetic marvels also have practical value. Each year a new layer of wood is added to the entire living surface of a tree. The size of these layers, which show up as rings when the tree is cut and viewed in cross-section or as lines in extracted cores, varies with the amount of nutrition and moisture the tree has obtained during the year. A dry year will produce a thin ring, a wet year a wide one. Over a period of time, tree rings form a distinct pattern that can be "read" by dendrochronologists and used to calibrate the results of carbon-14 dating, to determine short-term geologic erosion, or to help predict long-range weather patterns.

Findings at the Laboratory of Tree-Ring Research at the University of Arizona have led to a tree-ring chronology of over eight thousand years. An essential device aiding the research is the Swedish increment borer, a hollow drill that extracts a thin core from the wood without harming the tree - and a repeat of Curry"s experience in 1964.

The bristlecone pine is an irrepressible product of nature. It not only endures for centuries, but it also continues to propagate. Blown by mountain gales, the winged seeds are carried across ravines and valleys to lodge on some distant slope. Bristlecones a few feet high are found growing on remote, seemingly uninhabitable crags in the teeth of the wind, yet alive and producing cones. The bristlecone pine is an exquisite anomaly, a microcosm of adaptation to the environmental predicament.

Note Beyond: The Bristlecone Pine is frequently encountered in the Sangre de Cristo Wilderness. We often lay our hands on the trunks of these trees and think of them as our oldest living friends.