The Oldest Forest on Earth is Nearly 400 Million Years Old

 The recent discovery of tree fossils in southwestern England has revealed the existence of what is now considered the oldest known forest on Earth. These fossils, dating back 390 million years, surpass in age those of the fossil forest of Gilboa, in New York State, which dated to 386 million years. This finding, which challenges our understanding of early forest ecosystems, marks an important milestone in the study of forest evolution on our planet.

The evolution of trees and forests during the Devonian period played a crucial role in transforming our planet. By stabilizing the soil and interacting with the atmosphere and water cycles, trees profoundly altered terrestrial environments.

Starting in the mid-Givetian era (around 387 to 382 million years ago), a group of trees called lignophytes (the ancestors of modern trees that possess wood) became particularly influential in natural processes. However, the impact of earlier forests, primarily composed of cladoxylopsids (prehistoric trees that were not as woody as lignophytes), is less understood, which makes this new discovery all the more significant.

In a new study, a team of scientists reveals the existence of a 390-million-year-old cladoxylopsid forest in the Eifelian sandstone formation of Hangman, located in the Somerset and Devon regions of southwestern England. Previously, this area was considered to be of little paleobotanical interest, meaning in terms of plant fossils.

However, in addition to revealing the first fossils of this type of tree in the British record, this research also sheds light on the earliest evidence of the spatial arrangement of trees, which, simply put, constitutes the oldest known "fossil forest."

This ancient forest appears to have hosted only one species of plant. These plants looked similar to palm trees, with a long central stem and branches resembling palm fronds, though they were actually clusters of small branches. These trees, standing between two and four meters tall, made up a relatively low forest by today's standards.

The preservation methods of these fossilized trees are remarkable: some were preserved as hollow trunks filled with sediment, while others, fallen logs, were compressed over millennia, forming molds within the sediments. These fossils, still bearing the marks of branches, offer a unique glimpse into the structure and composition of these ancient trees.

It’s worth noting that at this time, present-day England was part of the Laurentia continent, near the equator, and thus enjoyed a warm and dry climate.

Moreover, this forest not only represents the first trees to have grown densely and closely together, but it also marks an ecosystem where the first terrestrial arthropods began to emerge. Researchers found traces of these small creatures in the sediments surrounding the fossilized trees, indicating early biodiversity.

This discovery will have major implications for our understanding of the evolution of forest ecosystems on Earth. It upends our understanding of early forests by revealing an ecosystem far older and more complex than previously thought. The existence of this fossil forest, with its prehistoric trees and traces of arthropods, offers an unprecedented glimpse into the biodiversity that was developing 390 million years ago. It also highlights the key role that these early environments played in transforming our planet. The analysis of these fossils opens new perspectives on the evolution of terrestrial ecosystems and the interaction between plant and animal life at that time.