Ohio State University researchers and their colleagues have discovered the remains of the northermost forest buried by a landslide that lived on the island two to eight million years ago, when the Arctic was cooling. The remains could offer clues to how today’s Arctic will respond to global warming.
The Ohio State team believe the trees -- and exquisitely preserved - will help them predict how today's Arctic will respond to global warming. They also believe that many more such forests could emerge across North America as Arctic ice continues to melt. As the wood is exposed and begins to rot, it could release significant amounts of methane and carbon dioxide into the atmosphere -and actually aggravate global warming.
Over the summer of 2010, the researchers retrieved samples from broken tree trunks, branches, roots, and even leaves -- all perfectly preserved -- from Ellesmere Island.
"Mummified forests aren't so uncommon, but what makes this one unique is that it's so far north. When the climate began to cool 11 million years ago, these plants would have been the first to feel the effects," said Joel Barker, a research scientist at Byrd Polar Research Center and the School of Earth Sciences at Ohio State University and leader of the team that is analyzing the remains. "And because the trees' organic material is preserved, we can get a high-resolution view of how quickly the climate changed and how the plants responded to that change," he added.
The researchers have identified the species of the most common trees at the site -- spruce and birch. The trees were at least 75 years old when they died, but spindly, with very narrow growth rings and under-sized leaves that suggest they were suffering a great deal of stress when they were alive.
"These trees lived at a particularly rough time in the Arctic," Barker explained. "Ellesmere Island was quickly changing from a warm deciduous forest environment to an evergreen environment, on its way to the barren scrub we see today. The trees would have had to endure half of the year in darkness and in a cooling climate. That's why the growth rings show that they grew so little, and so slowly."
Colleagues at the University of Minnesota identified the wood from the deposit, and pollen analysis at a commercial laboratory in Calgary, Alberta revealed that the trees lived approximately 2 to 8 million years ago, during the Neogene Period. The pollen came from only a handful of plant species, which suggests that Arctic biodiversity had begun to suffer during that time as well.
"I want to be clear -- the carbon contained in the small deposit we've been studying is trivial compared to what you produce when you drive your car," he said. "But if you look at this find in the context of the whole Arctic, then that is a different issue. I would expect other isolated deposits to be exposed as the ice melts, and all that biomass is eventually going to return to carbon dioxide if it's exposed to the air."
"It's a big country, and unless people decide to walk all across the Canadian Arctic, we won't know how many deposits are out there," he added.
Casey Kazan via The Ohio State University