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. In most ancient woods, the trees and shrubs have been cut down periodically as part of the management cycle. Provided that the area has remained as woodland, the stand is still considered ancient. Since it may have been cut over many times in the past, ancient woodland does not necessarily contain very old trees. For many species of animal and plant, ancient woodland sites provide the sole habitat, and for many others, conditions on these sites are much more suitable than those on other sites. Ancient woodland in the UK, like rainforest in the tropics, is home to rare and threatened species. For these reasons ancient woodland is often described as an irreplaceable resource, or 'critical natural capital'. The analogous term used in the United States, Canada and Australia (for woodlands that do contain very old trees) is "old-growth forest". 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. Protection Many ancient woodlands have legal protection of various types, but it is not automatically the case that any ancient woodland is protected. Some examples of ancient woodland are nationally or locally designated, for example as Sites of Special Scientific Interest. Others have no designations. Ancient woodlands also require special consideration when they are affected by planning application. The National Planning Policy Framework published in 2012 is the government policy document relating to planning decisions affecting ancient woodland. The importance of ancient woodlands as an irreplaceable habitat is set out in paragraph 118 of the NPPF, which states: ‘planning permission should be refused for development resulting in the loss or deterioration of irreplaceable habitats, including ancient woodland and the loss of aged or veteran trees found outside ancient woodland, unless the need for, and benefits of, the development in that location clearly outweigh the loss.’ Characteristics The concept of ancient woodland, rich in plant diversity and managed through traditional practices, was developed by