Earth's three trillion trees do a lot for us—make life possible, really—but how did they ever get started? Well, look no further than New York state. Scientists say they've found the world's oldest known forest in an abandoned quarry a couple hours north of Manhattan, the BBC reports. Dozens of 385-million-year-old trees left fossilized roots there, freezing a key moment in Earth's history. The find "is very special," team member Chris Berry tells 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." Not only that, the find pushes back our tree timetable by 20 million years and reveals rich, complex root systems much like modern ones.
Such trees also played a huge role in shaping our planet. Their deep roots snaked into the soil, breaking up rocks and causing chemical reactions that sopped up CO2 from the atmosphere. Called "weathering," this process helped cause CO2 levels to fall to modern levels and, by some research, allowed oxygen levels to reach 35% by 300 million years ago, spawning the evolution of enormous insects. "The arrival of these forests was the creation of the modern world," Berry tells the Smithsonian. In modern times Earth is going the other way, slashing forests and digging up ancient carbon to be burned for coal. That's sobering: "What's happening today is the opposite of what happened" millions of years ago, says lead author William Stein. (Read more discoveries stories.)