We know it’s been mere months since we told you the world’s oldest forest is in New York state, but scratch that: it’s actually in southwest England. At 390 million years old, a bunch of fossilized trees on the other side of the Atlantic has supplanted the US’s record by several million years.

Prior to the latest discovery, the oldest forest on Earth was believed to be 386 million years old and found in Cairo, New York state. But the fossilized trees nestled within the Hangman Sandstone Formation of Somerset and Devon are even older than that.

The formation, which dates to the Middle Devonian (393 million to 383 million years ago), was previously thought to contain only rare plant fossils, but new research has proven it to be far more abundant, including standing plant fossils and cladoxylopsids – an extinct group of plants related to ferns and sphenopsids (horsetails). 

Cladoxylopsids stood at around 2 to 4 meters (6.5 and 13 feet) high, meaning "it wouldn't have been a very tall forest," study lead author Neil Davies told Live Science. But what the trees lack in size, they make up for in age. 

In their study, Davies and co-authors present the earliest fossil evidence for such trees in Britain, as well as the oldest evidence of a fossil forest anywhere in the world.

"We've found rocks where you've got standing trees in growth positions adjacent to each other over a set area," Davies said, "so we're looking at a snapshot where we can tell for definite that there were trees growing in that specific location and that the sediment we're looking at is the forest floor."

As well as ample fossil evidence of the cladoxylopsid tree Calamophyton, the researchers found traces of other Middle Devonian flora and even signs of some ancient critters in the form of trackways.

What’s more, the sediment that the primitive plants were found in can shed some light on the impacts of the very earliest forests.

“The Hangman Sandstone Formation is illustrative of the revolutionary power of cladoxylopsid trees as biogeomorphic agents, forming densely spaced forests and shedding exceptionally abundant plant debris, whilst also impacting local landforms and sediment accumulations and profoundly changing landform resilience against flood disturbance events,” the study authors write. 

As such, they suggest that some 390 million years ago “mark[ed] the onset of tree-driven changes to physical environments that would forever change Earth’s non-marine landscapes and biosphere.” In other words, forests really started to take off.

This may be the oldest known fossil forest, but the oldest known living tree is significantly younger. At just 5,400 years old it’s practically a sapling compared to the cladoxylopsids of the Hangman Sandstone Formation. But both pale in comparison with sharks, which, at 450 million years young, are so old they’ve been around the galaxy twice.

The study is published in the Journal of the Geological Society.

[H/T: Live Science]