It is one of the largest areas of semi-natural (partially unmanaged) woodland in the UK. Wildlife species to be found in the forest include hawfinch, fallow deer, dipper, common crossbill, pied flycatcher, redstart, and long-eared owl among many other woodland birds and plants. The small but colourful moth "Oecophora bractella" has one of its few English populations here, and does not seem to occur much farther northwards.