Mad Bess Wood is part of Ruislip Woods Nature reserve and consists of 139 acres of woodland made up of several smaller woods. It is thought to be named after a local game keepers wife who lived nearby in the 18th century. Large areas of the wood are oak with hornbeam coppice, however there are also stands of sweet chestnut coppice in the wood. To the North East an old gravel quarry has led to more waterlogged conditions and the trees here are predominantly birch and alder. There are also very distinctive flora in this area of the wood including alder specific fungi, and moths including May Highflyer, Dingy Shell and Small Yellow Wave which are all specific to the alder. There have also been broad leaved helleborine and violet helleborine orchids found in the wood which are rare in this area. There is a car park at the wood and also several bridleways running through the site.