A fossilized tropical forest was unearthed in Svalbard, a Norwegian archipelago located in the Arctic Ocean. The scientists discovered some of the earliest trees to appear on the planet, offering them important clues on how Earth's climate dramatically changed 400 million years ago.
The British researchers uncovered several preserved tree stumps that were dated to 380 million years ago, during the Devonian period, an epoch that saw the progressive conquest of land by plants and trees.
The forest was extremely dense with trees as high as 4 meters tall (13 foot) separated by 15-20 centimeter (6-8 inch) gaps. It was composed by Lycopod trees, ancestors to those that covered the world during the carboniferous period and were eventually turned into coal.
"These fossil forests shows us what the vegetation and landscape were like on the equator 380 million years ago, as the first trees were beginning to appear on the Earth," said Dr. Chris Berry, lead author of the study, in a statement. During the Devonian, Svalbard was located near the equator and it slowly drifted to its current location over time due to plate tectonics.
This discovery could provide new information about the conditions of our planet during the Devonian. Scientists have evidence to suggest that the level of CO2 decreased significantly during this time and that this was due to the evolution of moss and small plants into trees and forests, which would soak up much more carbon dioxide and release oxygen.
"During the Devonian Period, it is widely believed that there was a huge drop in the level of carbon dioxide in the atmosphere, from 15 times the present amount to something approaching current levels,” Dr. Berry added. "The evolution of tree-sized vegetation is the most likely cause of this dramatic drop in carbon dioxide because the plants were absorbing carbon dioxide through photosynthesis to build their tissues, and also through the process of forming soils."
The trees discovered grew in wet areas, possibly a rapidly receding basin, the researchers found. Combined with the high density of vegetation, this produced stronger soil weathering compared to plants found in other fossilized forests, such as Gilboa in upstate New York, which had been studied previously by Dr. Berry in collaboration with American colleagues.
"This demonstrates that there was already geographical diversity of forest plant types and ecology just as soon as they had evolved," Dr. Berry said.
The paper is published in the journal Geology.