The narrow rods peeking out from the walls of the clay mine didn’t initially look like much. But as more of the spindly fossils appeared, paleobotanists Deming Wang and Min Qin soon realized they were in the midst of an ancient forest.

Discovered near the town of Xinhang, China, the fossilized tree trunks date back to about 365 million years ago, and cover at least 2.7 million square feet, which is roughly the size of 47 American football fields. This means they now represent the oldest forest yet found in Asia, the researchers report today in the journal Current Biology.

These prehistoric trees would not have looked like the woody, branched plants that shade our modern landscape, instead growing as