Forest of the Ancients.

High in the White Mountains of eastern California is a forest of trees that are among the oldest living things on earth. The Great Basin bristlecone pines are so ghostly, gnarled and ashen that they almost look their age: some trees are nearly 5,000 years old. The bristlecone pine thrives where almost nothing else does, in high-altitude ranges in California, Nevada and Utah. Their wood is so dense and full of resin that they are protected from insects and diseases that would easily kill other trees. (Even mighty California redwoods don't live beyond 2,000 years.) The rings of the bristlecones are startlingly accurate, preserving records of volcanic eruptions and celestial events (like meteor showers) and even helping scientists improve their estimates of historical events. The patriarch of the bristlecones -- known as Methuselah -- is older than the Great Pyramid of Giza. (The Methuselah Grove is accessible to hikers, but the tree itself is unmarked.) Yet for all their longevity, they are not invincible. The leading cause of death of ancient bristlecones, said Adelia Barber, a researcher at U.C. Santa Cruz, is fire. ''Some can survive lightning strikes,'' she said. ''But ultimately lightning sets the trees on fire, and they die.'' Maximum height of bristlecone pine: about 30 feet [ABSTRACT FROM AUTHOR]