This guide deals mainly with management of the semi-natural ash-dominated woods of western and northern Britain, which grow mostly on neutral and alkaline, often moist soils in a cool, wet and windy climate, from Cornwall to north-west Scotland. They are particularly characteristic of limestone districts, such as the Mendips, Pennines and around Morecambe Bay, where they form the most abundant type of semi-natural woodland, but they are also frequent on Old Red Sandstone in south Wales, the Jurassic limestone of the North Yorkshire Moors and limestone outcrops in Skye and elsewhere in north-west Scotland.
These last are the most northerly examples of this type in the world. Wherever they occur, they form the richest assemblages of flowering plants and often include rare and colourful species. There are estimated to be 40,000–50,000 ha of ancient semi-natural woodlands of this type.
