Bristlecone Pines, Living in Reverse
Near Great Basin Np, Nevada
Most trees look their age. Bristlecone pines do not. The ones growing at ten thousand feet on Wheeler Peak are not impressive in the way that redwoods are impressive. They are small. Their trunks are often stripped down to bare, pale wood by wind and ice, with a thin strip of living bark clinging to one side and a single tuft of needles at the crown. They look more dead than alive. That appearance is the key to their longevity.
A bristlecone pine in harsh conditions does something most plants cannot: it sheds the parts of itself it cannot feed and concentrates all its energy on what remains. When drought comes, or when a beetle infests one section of the tree, the bristlecone essentially amputates that branch and seals it off. The living tissue contracts. The dead wood, dense and resinous, resists rot for centuries. A tree can be more than half dead and still alive.
They grow so slowly that their wood has almost no air in it. A core the diameter of a drinking straw might represent three hundred years. Each ring is so thin that counting them requires a microscope and a calibrated stage. The oldest verified individuals have been growing at or above timberline, in rocky, nutrient-poor soil, at the upper limit of plant life in the Great Basin. The worse the conditions, it seems, the longer they live.
Great Basin National Park has three separate bristlecone groves. Wheeler Peak's grove, at about ten thousand feet on the north-facing cirque slopes, is the most visited, and it holds trees that are at least three thousand years old. The Mount Washington and Eagle Peak groves are in the southern part of the park, more remote, less traveled.
What bristlecone dendrochronology produced, beyond the Prometheus story, is a continuous tree-ring record extending back more than nine thousand years. By cross-dating living trees with dead wood preserved in the rocky soil, researchers built a chronology longer than any other. That chronology became the calibration standard for radiocarbon dating, which means that every carbon-fourteen date for an archaeological site anywhere in the world has been corrected, in part, against the record these trees have been keeping since before recorded history.
