Melting Ice Patch in the Rocky Mountains Reveals 5000-Yr-Old Greenery, Scientists Discover Over 30 Well-Preserved Dead Trees

An ice patch that has been melting in the Rocky Mountains of Wyoming has revealed an astonishing find: ancient whitebark pine trees that have been preserved under ice for almost 6,000 years, according to a study published in Proceedings of the National Academy of Sciences. The team discovered more than 30 well-preserved dead trees at 10,140 feet on the Beartooth Plateau, providing an unprecedented glimpse into the region's past climate conditions.
"A 5900-year-old whitebark pine forest has been discovered due to the melting of alpine ice in the Rocky mountains.
— kegasa (@kegasa2007) January 14, 2025
Scientists found more than 30 trees 3100 metres above sea level
– 180 metres higher than the present tree line –
on the Beartooth plateau in Wyoming." https://t.co/e1Rx895uTp pic.twitter.com/fUWQIwXZx7
The site of these ancient pines speaks volumes about the historical climate patterns. These trees were found growing at an elevation of around 590 feet above today's tree line—the highest elevation at which trees can survive today. "The plateau seems to have been the perfect place to allow for ice patches to establish and persist for thousands of years, recording important information on past climate, human activity, and environmental change," said Greg Pederson, lead author of the study and a paleoclimatologist at the United States Geological Survey, according to Smithsonian Magazine.
The exceptionally well-preserved condition of the trees makes the discovery all the more fascinating. Though they're lying flat now, their quality of preservation indicates it was quick embedding in ice—something that kept them perfectly preserved for at least several millenniums. Careful analysis done by tree ring and radiocarbon dating ultimately revealed that all these whitebark pines lived some 5,950 to 5,440 years ago under a period best known as the middle Holocene period.
Oh no. 😱
— Chris Martz (@ChrisMartzWX) January 14, 2025
A 5,900-year-old whitebark pine (Pinus albicaulis) forest has recently been revealed from beneath alpine ice receding on the Beartooth Plateau in northwestern Wyoming. They were found at an elevation of 3,100 meters, some 180 meters higher than the modern-day tree… pic.twitter.com/Tj0l8UFckQ
The trees' demise tells an equally compelling story about ancient climate change. Their final years coincided with a series of volcanic eruptions in the Northern Hemisphere that drastically changed the global climate. When volcanoes erupted, they belched debris into the atmosphere and created a kind of natural sunscreen effect, blocking enough sunlight to plunge the world into a significant cooling period. About 5,100 years ago, temperatures dropped so drastically that these high-elevation trees could no longer survive, and the growing ice patch eventually covered them.
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Kevin Anchukaitis, a paleoclimatologist at the University of Arizona, not involved with the study, referred to it as "a valuable time capsule" into both ancient mountain forests and the climate conditions that sustained them, stated Smithsonian Magazine. Craig Lee, a researcher in environmental archaeology at Montana State University, added that these kinds of long-term records are invaluable to understanding current climate patterns.

This is not yet the end of the story of the whitebark pine. Listed currently under the Endangered Species Act as "threatened," these hardy trees are challenged in multiple ways: rising temperatures, drought, wildfires, and threats from mountain pine beetles and white pine blister rust, as per Smithsonian Magazine. Yet it's not a tale without hope. Healthy whitebark pines have been known to live up to a millennium; they are major contributors to high-elevation ecosystems, providing food for a suite of wildlife, from bears and Clark's nutcrackers to squirrels and jays, while helping to moderate snow conditions due to their shade.