The oldest petrified forest ever discovered on Earth (390 million years old) was located in high sandstone cliffs off the coast of Devon and Somerset in south-west England. The fossils discovered and identified by researchers from Cambridge and Cardiff Universities are the oldest fossilized trees found in England and the oldest known fossil forest in the world. This fossil forest is about four million years older than the previous record holder, located in New York state.

The fossils were found on the south bank of the Bristol Channel, near Minehead, near what is now Batlin Holiday Camp. Known as petrified trees calamophytonAt first glance, they look like palm trees, but they were the “prototype” of the trees we know today. Their bodies were thin and hollow in the middle rather than solid wood. It also had no leaves and its branches were covered with hundreds of twigs.

These trees were also significantly shorter than their descendants: the largest were two to four meters tall. As the trees grew, they shed their branches and deposited on the forest floor much plant litter that supported invertebrates.

Geological significance

Scientists had previously assumed that this part of Britain’s coastline contained no significant plant fossils; But this particular fossil find, in addition to its age, also shows how the first trees helped shape the landscape and solidify riverbanks and shorelines hundreds of millions of years ago. The results are reported as follows: Geological Society journal.

The history of the forest dates back to the Devonian period, between 419 and 358 million years ago, when the first major expansion of life on land began: by the end of the period, the first seed plants appeared and the first land animals, mostly arthropods, were well established. .

“The Devonian period fundamentally changed life on Earth,” said the study’s first author, Professor Neil Davies from Cambridge’s Department of Earth Sciences. “It also changed water-soil interactions as trees and other plants helped stabilize sediments through their root systems, but little is known about the oldest forests.”

Ecological ideas and research methodology

The fossil forest identified by the researchers was found in the Hangman Sandstone Formation off the coast of north Devon and west Somerset. During the Devonian period this area was not connected to the rest of Britain, but was located further south and was connected to parts of Germany and Belgium where similar Devonian fossils have been found.

Co-author Dr. from Cardiff School of Earth and Environment. “When I first saw the photographs of the tree trunks, I immediately knew what they were, based on 30 years of research on such trees around the world,” said Christopher Berry. Sciences. “It was amazing to see them so close to home. But the most revealing insight comes when we first see these trees where they grow. This is our first opportunity to look directly at the ecology of this oldest forest type to interpret the environment in which the trees grow.” Calamophyton and evaluate their effects on the sedimentary system.”

Field research along Britain’s highest sea cliffs, some of which can only be reached by boat, has shown that this sandstone formation is actually rich in fossil plant material from the Devonian period. Researchers identified fossilized plant and plant remains, fossilized tree stumps, root traces and sedimentary structures preserved in the sandstone. In the Devonian, the region was a semiarid plain intersected by small river channels flowing northwest from the mountains.

“It was a pretty strange forest, unlike any forest you’d see today,” Davis said. “There wasn’t any undergrowth worth mentioning and the grass wasn’t out yet, but there were a lot of branches that had fallen by these dense trees, making a huge impact on the landscape.”

This period was the first time when densely packed plants could grow on land and trees shed large amounts of debris. calamophyton , formed in sediment layers. Sediments affected the way rivers flowed across the landscape, and for the first time river beds could be affected in this way.

“The evidence contained in these fossils preserves a key stage in Earth’s development when rivers began to function in a completely different way than before, becoming the major erosive force they are today,” Davis said. “People sometimes think British rocks have been understudied, but this shows that revisiting them can lead to important new discoveries.”