Newswise — Charles Ver Straeten, curator of sedimentary rocks at the New York State Museum, stood on the crumbling stone of an old quarry when his eye caught a pattern.
In 2009, he was scouting out the area with colleagues Linda Van Aller Hernick and Frank Mannolini for a potential field trip — nothing unusual, since paleobotanists have been visiting the former highway department property since the 1960s. The famous Gilboa fossil forest, discovered a century ago, is a short jaunt up the road from Cairo, New York.
Something seemed out of place: His trained eye spied wandering gutters in the stone, a feature common to marine rocks. But even in the Middle Devonian period, the swathe of land that one day became Cairo wasn’t at the bottom of the sea.
He traced eleven of the lines to a single point and then realized what they showed: the roots of an ancient and very large tree, at a time when forests were still new in the world. By tracing root impressions, researchers have been able to map out the world’s oldest forest tree by tree, a forest 2 million years older than the one in Gilboa.
Studied by researchers from Binghamton University and around the world, the Cairo site has been diligently shielded from view to protect it from fossil hunters and potential damage. That may someday change.
Through New York State Senator Michelle Hinchey, the town received a $170,000 grant to construct specialized fencing around the property, supported by concrete barriers to protect the fossil forest below, according to Joe Hasenkopf, chair of the Cairo Planning Board. The next step would be a feasibility study to explore the possibility of an educational center and working lab on the site, which would serve not only researchers and students, but the public at large.
Last year, the state government passed a law that established a New York state geological trail and geopark system; Cairo is slated to be one of the first of these parks, Hasenkopf pointed out. That opens up additional funding opportunities for the future.
There is much to learn from these ancient root impressions, researchers say, and protecting the site will allow future scientists and students to explore this ancient world.
“The in-situ preserved forest floors such as the one in the Town of Cairo are the rarest fossil records. Its preservation is a great contribution to the study of the evolution of early trees, forest ecosystems, past climates and landscapes, and possibly the earliest land animals,” said Khudadad, who earned his doctorate in biological sciences from Binghamton in May. (Khudadad uses a single name.) “There are plenty of unanswered questions that need to be investigated by current and future scientists, and such preservation attempts are definitely a great gift to future generations.”
New book, old forest
The public doesn’t have to wait for a future educational center to learn about this ancient forest. This July, the Gilboa Historical Society released The Catskill Fossil Forest, which traces the history of the ancient forest from its initial discovery in the 1800s, through the construction of the Schoharie Dam and current research in Gilboa, Conesville and Cairo.
Co-authored by Emeritus Professor of Biological Sciences William Stein along with Van Aller Hernick and Mannolini, the short book not only explains the forest’s scientific significance and what the forest may have looked like, but also includes lavish illustrations and photos of digs. Sales of the book benefit the Gilboa Museum and Juried History Center, important supporters of research efforts at the Cairo and Gilboa sites, Stein said.
“In our book, we explain that both (the Cairo and Gilboa) sites and the one at Conesville, somewhat younger yet, likely record different aspects of essentially the same forest lasting several millions of years in the Catskill region,” Stein explained. “These sites together currently record the best evidence worldwide of forests during this time period.”
The Gilboa site was first dubbed the “world’s oldest forest” in the 1920s, courtesy of the New York State Museum’s Winifred Goldring. The ancient forest in Cairo is slightly older than the one in Gilboa, at 387 million years, Stein said.
The Cairo and Gilboa sites are unique in that they show the root systems of individual trees within the ancient soil. Like dinosaur footprints, these root structures give scientists a glimpse into the behavior of living organisms — or, in this case, forest ecology.
Knowledge has progressed since the 1920s, and researchers understand more about the composition and structure of these ancient forests, and their impact on global processes such as climate, river geometry and nutrient cycling in both terrestrial and marine environments during the Devonian Period, Stein said. But debate on what constitutes the “oldest” forest continues, as well as what constitutes a “tree” and a “forest,” he said. After all, forests during the Devonian Period weren’t much like those in New York state today.
During that time, New York state was a warmer place, located south of equator. The Appalachian Mountains were young and still growing, and the source of river systems that drained into a shallow sea that is now the Appalachian basin, Khudadad said.
Most landscapes around rivers were still barren, as the planet’s land surface began to green; forests were still a new development. And they were fragile; if a river shifted course and took out a forest, it didn’t regenerate, Khudadad found in his research.
Seeds hadn’t yet developed, so the trees reproduced by microscopic spores. Early trees came in three types: Eospermatopteris, which resembled a palm tree in shape; lycopsid trees, which are related to modern club mosses and horsetails; and the conifer-like Archaeopteris. While young forests were often limited to a single type of tree, all three could grow together in complex forests located in river floodplains, Khudadad found.
Trees and soils, which were transformed by tree roots, drew down carbon dioxide from the atmosphere, leading to the global cooling seen during the Paleozoic era. Known as paleosols, these ancient soils hold not only the records of primitive trees but past climate change, Khudadad said. Through the creation of green corridors, ancient forests like the one in the Catskills also helped facilitate the transition of fish into tetrapods — and eventually dinosaurs and all the land animals that followed, Khudadad said.
There’s still a lot to learn about the ancient Catskills, and that long-ago period of time when the first forests spread across the landscape, helping cool the climate. These lessons could even give some insight into our future under climate change.
“It is no exaggeration to say that event was unique in Earth’s history and of highest importance to understanding how Earth’s systems interconnect,” Stein said. “Devonian ‘afforestation’ is essentially the same process but in reverse to what’s happening today: deforestation, burning fossil fuels, with related increase in climate mean temperature.”