Melting Ice Reveals Ancient Forest in the Rocky Mountains
Ancient Forest Unearthed as Ice Melts in the Rocky Mountains
A forest buried beneath ice for nearly 6,000 years is now basking in daylight once more, thanks to warming temperatures in the Rocky Mountains.
The ancient whitebark pine forest was discovered by a team of scientists from Montana State University, the U.S. Geological Survey, and collaborating institutions during an archaeological survey on Wyoming’s Beartooth Plateau. The forest, located at approximately 3,000 meters above sea level—180 meters higher than the current tree line—was revealed as ice patches melted away.
“We were really surprised to find a forest emerging from the ice margins. It was amazing,” said Cathy Whitlock, professor of Earth sciences at Montana State University, in an interview with As It Happens host Nil Köksal.
The team identified about 30 well-preserved trees, carbon dating them to between 5,950 and 5,440 years ago. The findings, published in the Proceedings of the National Academy of Sciences on December 30, 2024, shed light on the region’s high-elevation environment thousands of years ago.
A Mixed Discovery
Whitlock described the discovery as both exciting and bittersweet. While the trees offer a rare glimpse into the past, their unveiling underscores the impact of modern climate change.
“I’m thrilled because it’s a window on the past,” she said. “But as someone concerned about the future, it makes me really sad. These ice patches are melting, and they probably won’t be there in a few decades.”
Chainsaws were used to cut slabs from the ancient logs, enabling researchers to study tree rings and carbon date the remains. The rings revealed not only the trees’ age but also the environmental conditions they experienced.
“This was a well-developed forest,” Whitlock said. “These were tall-standing trees, not the scruffy ones typically found near treeline.”
About 5,000 years ago, cooling temperatures caused an ice patch to form, which killed and eventually buried the forest. The melting of these patches today offers stark evidence of the rapid warming taking place in our time.
“What took thousands of years in the past is happening over decades today,” said Colin Laroque, a University of Saskatchewan professor specializing in tree age estimation, who was not involved in the study.
Future Research and Concerns
Similar discoveries have occurred in other regions, such as British Columbia’s Coast Mountains. Whitlock’s team plans to continue investigating the Beartooth Plateau ice patch, analyzing its chemical composition to better understand past climate shifts.
“We don’t yet fully understand these high-elevation forests or how they will respond in the future,” Whitlock said.
As temperatures continue to rise, current treelines may advance to higher elevations, potentially reviving ancient forests. However, this shift could lead to significant consequences, such as the loss of vital snowpack—a critical source of water for the West.
“With warming temperatures, we’re losing snowpack,” Whitlock explained. “More precipitation falls as rain instead of snow, and it melts earlier. This will contribute to the West becoming drier.”
Whitlock’s findings emphasize the sensitivity of high-elevation ecosystems to climate fluctuations. “Even small amounts of warming can shift these environments from tundra to forest,” she noted. “It’s a powerful reminder of how interconnected and vulnerable our planet is to climate change.”
