Cairo Forest: The world’s oldest forest is 387 million years old! 

Trees live for an astoundingly long number of years. In fact, some species of trees live up to thousands of years! Therefore, the forests these trees make up date back to the Pleistocene epoch, often referred to as the Ice Age (2.6 million to 11,700 years ago). One such forest is present in an abandoned quarry near Cairo, New York, and is called the ‘world’s oldest forest’. In 2012, scientists declared another forest to be the oldest ever and named it ‘Gilboa’s fossil forest’. However, in 2019, they postulated that the Cairo Forest may be 2–3 million years older than the Gilboa forest, with an estimated age of 385 million years (Devonian period). This understanding made the Cairo Forest around 140 million years older than the earliest dinosaurs to roam the planet! Unbelievable, right? Let’s explore some other amazing aspects about this ancient forest.  

Cairo Forest and the inception of human life 
Scientists have postulated that the fossilised woody roots present in the ancient Cairo Forest have helped trap carbon dioxide (CO₂) from the environment. This may have significantly modified the atmosphere during Earth’s formation, fostering the development of life. Kevin Boyce, a geoscientist at Stanford University, asserts that the prehistoric climate was significantly influenced by trees such as those in Cairo, New York. Through a process known as weathering, the roots of these trees penetrated and disintegrated the rocks beneath the soil’s surface. This triggered a chemical process that helped trap CO₂ from the atmosphere. Soon after the formation of this forest, atmospheric CO₂ levels decreased to levels that could foster life. Thus, the emergence of trees and forests during the mid-Devonian period was a key point in Earth’s history, contributing to long-lasting changes to aspects such as the ecosystem, CO₂ levels and climate.  

What did this forest look like? 
Khudadad, a Binghamton University doctoral candidate, found that the Gilboa Forest was predominated by fern-like trees of the genus Eospermatopteris (a genus of now extinct plants). However, his research on the older Cairo Forest revealed something different. This ancient woodland was situated next to an old river channel and had a variety of other trees including the conifer-like Archaeopteris, along with the members of the genera Eospermatopteris and Lycopsid. 

How did the geography of this region support the growth of these forests? 
In the Middle Devonian period, the Catskill River, originating from the ancient Catskill mountains, played a significant role in the establishment of ancient forests such as the Cairo and Gilboa Forests. This river system snaked along the plains, which gradually broadened; the resulting deltaic conditions supported trees of the genus Eospermatopteris.