World's oldest fossil forest discovered in New York

December 23, 2019, 8:30 a.m.
Overview of Archaeopteris in greenish overwash sediment.
Photo: William Stein and Christopher Berry

When researchers were exploring an abandoned quarry in Cairo in the Catskills region of New York, they came across an elaborate fossilized root system on the site. They discovered that the labyrinth of snaking tree roots was 386 million years old and belonged to dozens of ancient trees.

"The Cairo site is very special," team member Christopher Berry, a paleobotanist at Cardiff University in the United Kingdom, told Science. "You are walking through the roots of ancient trees. Standing on the quarry surface we can reconstruct the living forest around us in our imagination."

Berry and her team first discovered the roots in 2009 and have been working to analyze all the fossils on the site. Some of the roots are nearly 6 inches (15 centimeters) in diameter and spread out into web-like patterns that are 36 feet (11 meters) wide.

Overview of well-preserved Archaeopteris root system, left, possible Stigmarian Isoetalean lycopsid, right. Overview of a well-preserved Archaeopteris root system (left) and a possible Stigmarian Isoetalean lycopsid. (Photo: William Stein and Christopher Berry)

Many of the roots belong to Archaeopteris, a tree with large roots and woody branches that's an ancestor of today's modern trees, the researchers report in Current Biology. (You can see the roots of Archaeopteris in the photo directly above and more clearly in the photo at the top of this file.)

The trees were one of the earliest to take carbon dioxide from the air and store it. Their deep roots would break up the soil, triggering chemical reactions that would pull CO2 from the atmosphere.

"All these trees appearing was having an effect of removing carbon dioxide from the atmosphere," Berry told New Scientist. "By the end of the Devonian period [360 million years ago], the amount of carbon dioxide was coming down to what we know it is today."

So far, researchers have mapped more than 32,000 square feet (3,000 square meters) of the forest. They say they hope to compare their findings to other forests around the world.

"It seems to me, worldwide, many of these kinds of environments are preserved in fossil soils. And I'd like to know what happened historically, not just in the Catskills, but everywhere," lead author William Stein, an emeritus professor of biological science at Binghamton University, New York, said in a release. "Understanding evolutionary and ecological history — that's what I find most satisfying."