Coolest trees ever: Study: Svalbard forest caused one of Earth’s most dramatic climate shifts 400M years ago


The irony is almost too much: A prehistoric forest in Svalbard that reduced atmospheric CO2 15-fold was full a type of tree grown in swamps that produced the coal now pushing up that pollutant to dangerous levels.

Of course, all this is only possible because Svalbard was at the equator 400 million years ago and is now in a literal polar opposite setting at the top of the world, where a team of modern-day researchers discovered the fossilized remains of the forest.

“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 Chris Berry, a senior lecturer at Cardiff University’s School of Earth and Ocean Science, in a statement released by the university this week.


A rocky outcrop in Svalbard contains 12 numbered casts of upright lycopsid trunks from a prehistoric forest that existed about 400 million years ago, when the archipelago was near the equator. Photo courtesy of Michael Bishop / Cardiff University.

Current theories suggest the Devonian period (420-360 million years ago) saw a huge drop in the level of atmospheric CO2 due to a change in vegetation from diminutive plants to the first large forest trees, according to the statement. Svalbard’s fossil forests, discovered at Plantekløfta in Munindalen with tree stumps preserved in place, consist “mainly of lycopod trees, better known for growing millions of years later in coal swamps that eventually turned into coal deposits – such as those in South Wales.”

“They also found that the forests were extremely dense, with very small gaps – around 20 centimeters – between each of the trees, which probably reached about four meters high.…Because of the high temperatures and large amount of rainfall on the equator, it is likely that equatorial forests contributed most to the drawdown of CO2.”

The study, published in the current journal Geology, states the both of density and character of the trees made them idea CO2 consumers.

“This high-tree-density tropical vegetation may have promoted rapid weathering of soils, and hence enhanced carbon dioxide drawdown, when compared with other contemporary and more high-latitude forests,” the study notes.

Although initially the appearance of large trees absorbed more of the sun’s radiation, eventually temperatures on Earth also dropped dramatically to levels very similar to those experienced today because of the reduction in atmospheric CO2, according to the study.

Berry also participated in a study where a slightly older forest was found in New York, which at the time was at least 30 degrees south of the equator.

“This demonstrates that there was already geographical diversity of forest plant types and ecology just as soon as they had evolved,” he said.

And while some of their cousins ended up contributed to today’s rising CO2 levels, Berry noted the Svalbard discovery occurred where preservation efforts against another type of seismic shift are occurring in the global seed vault.

“It’s amazing that we’ve uncovered one of the very first forests in the very place that is now being used to preserve the Earth’s plant diversity,” he said.