Ancient woods are areas of woodland that have persisted since 1600 in England, Wales and Northern Ireland, and 1750 in Scotland. This is when maps started to be reasonably accurate so we can tell that these areas have had tree cover for hundreds of years. They are relatively undisturbed by human development.

At 385 million years old, the ancient woodland predates the rise of seed-producing plants, a group that includes almost all living trees. The Paleozoic forest is also home to the remnants of intricate tree root systems that bear an uncanny resemblance to those still around today.