In the United Kingdom, an ancient woodland is a woodland that has existed continuously since 1600 or before in England, Wales and Northern Ireland (or 1750 in Scotland). Planting of woodland was uncommon before those dates, so a wood present in 1600 is likely to have developed naturally. Ancient woodland is formally defined on maps by Natural England and equivalent bodies. Mapping of ancient woodland has been undertaken in different ways and at different times, and the quality and availability of data varies from region to region, although there are some efforts to standardise and update it.