Earth's oldest forest is nearly 400 million years old

The discovery of tree fossils in southwest England has revealed the existence of what is now considered the oldest known forest on Earth. These fossils, dating back 390 million years, are older than those from the Gilboa Fossil Forest in New York State, which was 386 million years old. This discovery, which challenges our understanding of primitive forest ecosystems, marks an important milestone in the study of the evolution of forests on our planet.

Transformative prehistoric trees

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

Beginning in the mid-Givetian era (approximately 387 to 382 million years ago), a group of trees called lignophytes (the ancestors of modern trees that possess wood) became particularly influential in the processes natural. However, the impact of older forests, composed mainly of cladoxylopsids (prehistoric trees that were not as woody as lignophytes), is less known and understood, hence the interest of this new discovery.

The oldest known “fossil forest”

In a new study, a team of scientists reveals the existence of an ancient cladoxylopsid forest 390 million years old in the Eifelian Hangman Sandstone Formation, located in Somerset and Devon, in the southwest of England. Previously, however, this area was considered to have little paleobotanical interest, that is to say in terms of plant fossils.

However, in addition to revealing the first fossils of this type of tree in the British archives, this research also highlights the oldest evidence to date of the spatial arrangement of trees , which, in simple terms, constitutes the oldest known “fossil forest” .

A forest cover very different from today

This ancient forest appears to have been home to only one species of plant . These plants had a similar appearance to palm trees, with a long central stem and branches that resemble palm leaves, although they are actually just a collection of small branches. These trees, which measured between two and four meters high , made up a relatively low forest by today's standards.

The methods of preserving these fossil trees are remarkable: some were preserved as hollow trunks filled with sediment, while others, fallen logs, were compressed over millennia, forming casts within the sediment. These fossils, which still bear the marks of the branches, offer a unique insight into the structure and composition of these ancient trees.

Note that at this time, what is now the United Kingdom was on the continent of Laurentia, near the equator, and therefore enjoyed a warm, dry climate .

Furthermore, this forest not only represents the first trees to grow en masse and closely together, but it also demonstrates an ecosystem where the first terrestrial arthropods were beginning to emerge. Researchers have indeed found traces of these small creatures in the sediments surrounding the fossil trees, which indicates emerging biodiversity.

This discovery will have major implications for our understanding of the evolution of forest ecosystems on Earth. It suggests that forest environments were already experiencing rapid expansion at this time, marking a decisive turning point in the history of terrestrial vegetation.

Details of the study are published in the Journal of the Geological Society .