The world’s oldest known fossil forest has been discovered in a sandstone quarry in the town of Cairo, in upstate New York, offering new insights into how trees transformed the planet.
The forest would have spanned from New York to Pennsylvania and beyond, and has been dated to about 386m years old. It is one of only three known fossil forests dating to this period and about 2-3m years older than the previously oldest known fossil forest at Gilboa, also near Cairo.
The forest would have been quite open and its ancient trees would appear alien to the modern eye. A walker would have encountered clusters of Cladoxylopsid, a 10m-tall leafless tree with a swollen base, short branches resembling sticks of celery and shallow, ribbon-like roots. The fossils also revealed a tree called Archaeopteris, something like a pine, but instead of needles the branches and trunk were adorned with fern-like fronds, giving it an almost hairy appearance.
The prehistoric forest would have been sparse on wildlife but would have been home to primitive insects about 150m years before dinosaurs evolved. The forest’s primary occupants were millipede-like creatures, called myriapods, and some other primitive insects that may or may not have begun to fly. There were no vertebrates on land yet and no birds.
The emergence of forests is one of the most transformative events in Earth’s history, marking permanent changes to ecology, atmospheric CO2 levels and climate. Before forests, CO2 levels were far higher and the Earth’s climate was hotter with no ice caps. By the end of the Devonian period, about 350m years ago, there were glaciers and, soon after, polar ice became permanent.
However, there have been so few fossil remains of early trees that scientists have had only a hazy idea of which trees dominated which habitats, how root systems altered soil chemistry and how forests opened up new ecological niches for animals.
Story excerpted from The Guardian