Ancient and semi-natural woodland
Ancient semi-natural woodland (ASNW) tends to be richer in plants and animals than other woodland areas. The area of ASNW has declined over the centuries and woodlands have become increasingly fragmented. In a 2001 report it was estimated to total 326 thousand hectares, of which almost two-thirds was in England. Later estimates, produced by overlaying the Ancient Woodland Inventory on the National Inventory of Woodland and Trees, give lower figures, but are not considered reliable.
Table 4.1 Ancient and semi-natural woodland
Not National Statistics.
1. Ancient woodland is woodland that has been in continuous existence since 1600 (1750 in Scotland);
Semi-natural woodland is woodland with natural characteristics (predominantly native species of trees, ground plants and animals).
2. ASNW (ancient semi-natural woodland) is both ancient and semi-natural;
PAWS (plantation on an ancient woodland site) is ancient but not semi-natural;
OSNW (other semi-natural woodland) is semi-natural but not ancient.