White bar pines discovered
Gregory Pederson
A 5,900 -year -old white pine forest was discovered due to the merger of Alpine ice in the rocky mountains. Scientists have found more than 30 trees About 3100 meters above sea level – 180 meters higher than the current trees line – while carrying out an archaeological survey on the Beartooth plateau in Wyoming.
This “offers us a window on the conditions spent at high altitude”, says Cathy Whitlock at the Montana State University. White pine (Pinus Albicaulis) Do not grow at this altitude now, so these should grow at a time when the climate was warmer, she said.
To understand the history of the lost forest, Whitlock's team analyzed its rings and used carbon dating to age. They found that the trees lived from 5950 to 5440 years, a period of temperatures reduced regularly.
Data on ice nuclei from places like Antarctica and Greenland suggest that these lowered temperatures have been influenced by volcanic eruptions of several centuries in the northern hemisphere. These produced enough air sediment to cut sunlight and lower global temperatures until environment It was too cold for these higher trees to survive.
While being flat, the newly discovered trees are in exceptional condition, indicating that they were quickly preserved after death. Although they lack evidence of being covered by avalanches, they show notes that align with the expansion of the current ice plot.
Climate models suggest that additional volcanic eruptions in Iceland have produced new temperature drops 5100 years ago, explains the team member Joe McConnell At the Desert Research Institute in Nevada. These lower temperatures have expanded the ice patch and assured that “the fallen trees were buried in the ice and protected from the elements for the next 5000 years,” he said.
It was only in recent decades that temperatures have increased enough to release the trees from their ice crypt. The line of the current tree structure is “likely to move the useful slope with the increase in temperatures in the coming decades”, explains Whitlock.
“This discovery was possible due to anthropogenic climate change – the increase in temperatures now expose areas that have been buried by ice for millennia,” she said. “Although such discoveries are scientifically interesting, they are also a sad reminder of the way in which alpine ecosystems are fragile to climate change.”
“The study is a very elegant and meticulous use of a precious” temporal capsule “which tells us not only these mountain forests 6000 years ago, but on the climatic conditions which allowed them to exist”, explains Kevin Anchukaitis at the University of Arizona.
These trees are not the first researchers of this type that researchers discovered plots of rocky mountain ice. Previous work has found “wooden trees fragments used for arrows and darts,” explains Whitlock. A tree was radiocarbon dated more than 10,000 years ago, “telling us that people have hunted in high altitude environments for millennia,” she said.
