Ancient woodland: Encyclopedia - Ancient woodland

Ancient woodland

Ancient Woodland is a term used in the United Kingdom to refer specifically to woodland dating back to at least 1600 in England and Wales, (or 1750 in Scotland). Before this, planting of new woodland was uncommon, so a wood present in 1600 was likely to have developed naturally.

Ancient semi-natural woodland (ASNW) is composed of native tree species that have not obviously been planted. Planted ancient woodland sites (PAWS) are ancient woods in which the former tree cover has been replaced, often with non-native trees; features of ancient woodland often survive in many of these woods too, including characteristic wildlife, and structures of archaeological interest.

Species which are particularly characteristic of ancient woodland sites are called ancient woodland indicator (AWI) species. The term tends to be applied more commonly to plant species than to animals, as they are slower to colonise planted woodlands, and are thus viewed as more reliable indicators of ancient woodland sites. Lists of ancient woodland indicator species among vascular plants have been developed by the Nature Conservancy Council for each region of England - each list containing the 100 most reliable indicators for that region. The methodology used involved studying the flora of known woodland sites and analysing occurrence patterns to determine which species were most indicative of sites which existed before 1600. Although ancient woodland indicator species can & do occur in non-ancient woodlands, and also in non-woodland sites such as hedgerows, it is uncommon for a site which is not ancient woodland to host a double-figure AWI species total.

Ancient woods over 20,000 square metres in size are recorded in Ancient Woodland Inventories (AWIs), compiled in the 1980s and 1990s by the Nature Conservancy Council in England, Scotland and Wales and maintained by its successor organisations in those countries. There is currently no inventory in Northern Ireland but the Woodland Trust is compiling one to be completed in 2006.

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. For these reasons conservation organisations often describe ancient woodland as an "irreplaceable" resource.

Britain's ancient woodland cover has declined greatly. Since the 1930s almost half of ancient broadleaved woodland in England and Wales has been planted with conifers or cleared for agriculture. Only 3,090 square kilometres of ASNW survive in Britain – less than 20% of the total wooded area. More than 8 out of 10 ancient woods in England and Wales are less than 200,000 square metres, only 501 exceed 1 square kilometre and a mere 14 are larger than 3 square kilometres. (Source The Woodland Trust, UK woodland charity).

Adapted from the Wikipedia article "Ancient woodland", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki