Fossilized trees discovered by chance in southwest England belong to Earth's earliest-known forest, new research has found. The 390 million-year-old fossils supplant the Gilboa fossil forest in New York state, which dates back 386 million years, as the world's oldest known forest.

The new discovery highlights differences between the two ecosystems, suggesting forests went from being relatively primitive to well established over the course of just a few million years, said Neil Davies, the lead author of a new study published Feb. 23 in the Journal of the Geological Society.

"Why it's important — broadly — is it ticks the boxes of being the oldest fossil forest," Davies, a professor in the Department of Earth Sciences at the University of Cambridge in the U.K., told Live Science. The finding is also remarkable because it reveals stark differences between the complex array of ancient plants found at Gilboa and the newly discovered forest, which appears to have hosted just one type of plant, Davies said.