High on the top of California's White Mountains, the hard conditions make it difficult for life to take root. But for a certain type of tree—and for those who have travelled here to study it—this place is a perfect place.
These bristlecone pines are the oldest individual trees in the world. Researchers like Andy Bunn have come to learn from the ancients. "It's remarkable to sit here and have your hand on one of these trees and know that it was growing when the Pyramids were built. " Bunn added.
"By studying samples (样本) from the trunks, it's possible to discover their hidden history. Each annual tree ring is like a time capsule of the environment for that year from which it was formed," said Matt Salzer, a scientist at the University of Arizona's Laboratory of Tree Ring Research. "And it contains many different types of information—chemical information, the information on growth, and climate information. "
"If you're trying to look at people in the past through time, tree rings give you a way to do it in a way that makes sense in a human life," said University of Arizona Professor Charlotte Pearson. She first became fascinated with the bristlecones after reading about an ancient volcanic eruption on the Greek island of Santorini. "It blew my mind that trees on the other side of the world could possibly be used to date this thing within a single year," she said excitedly.
The oldest known living bristlecone is estimated to be over 4,800 years old. For Bunn, the climate record written in the rings offers guidance for how we might think about what's happening in the present as we plan for the future. "What we're seeing increasingly is that a lot of the climate events that we are experiencing and living through right now have no example in the paleoclimate (古气候) record," he said. "So, we really are moving into unknown field."