Ancient Arctic Forests
In the Arctic, trees and forests just do not happen. However, long ago they did when the area was warmer and then turned cooler. As it turns out there are many such northern forests that have been preserved by mineralization and similar processes. The northernmost mummified forest ever found in Canada is revealing how plants struggled to endure a long-ago global cooling. Researchers believe the trees -- buried by a landslide and exquisitely preserved 2 to 8 million years ago -- will help them predict how todayâ€™s Arctic will respond to global warming.
Axel Heiberg Island is an island in the Qikiqtaaluk Region, Nunavut, Canada. Located in the Arctic Ocean, it is the 31st largest island in the world and Canada's seventh largest island. According to Statistics Canada, it has an area of 16,671 square miles.
One of the larger members of the Canadian Arctic Archipelago, it is also a member of the Sverdrup Islands and Queen Elizabeth Islands. It is known for its unusual fossil forests, which date from the Eocene period. Owing to the lack of mineralization in many of the forest specimens, the traditional characterization of "fossilisation" fails for these forests and "mummification" may be a clearer description. It is clear that the Axel Heiberg forest was a high latitude wetland forest.
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, will describe early results at the American Geophysical Union meeting in San Francisco.
Over the summer of 2010, the researchers retrieved samples from broken tree trunks, branches, roots, and even leaves -- all perfectly preserved -- from Ellesmere Island National Park in Canada.
The fossil forest, which lies outside the borders of the new Quttinirpaaq National Park (formerly Ellesmere Island National Park) on Ellesmere Island, is unprotected from the damage that visitors can inflict.
"Mummified forests arenâ€™t so uncommon, but what makes this one unique is that itâ€™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," Barker said. "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."
Analysis of the remains has only just begun, but will include chemical and DNA testing.
For now, 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 Arcticâ€ 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. Thatâ€™s why the growth rings show that they grew so little, and so slowly."
"I want to be clear -- the carbon contained in the small deposit weâ€™ve been studying is trivial compared to what you produce when you drive your car,â€ he said. â€œBut if you look at this find in the context of the whole Arctic, then that is a different issue."
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. The whole Neogene period lasted about 23 million years and saw the rise of early Man,
Now that the forest is exposed, itâ€™s begun to rot, which means that itâ€™s releasing carbon into the atmosphere, where it can contribute to global warming. How many such forests exist buried in the arctic ice waiting to be exposed is not known. The next effect on global climates is not yet known.
Examination of this ancient forest can reveal clues as to how plants adapt to a cooling environment.
For further information: http://researchnews.osu.edu/archive/mumforest.htm