Backstone Bank and Baal Hill Woods one side valley, there is a small population of small-leaved lime, "Tilia cordata", which occurs here close to its northern limit and at an unusually high altitude. On base-rich soils, the woodland typically consists of ash, "Fraxinus excelsior", and wych elm, "Ulmus glabra", over an understorey of hazel, "Corylus avellana", and bird cherry, "Prunus padus", and a rich ground flora that includes lady-fern, "Athyrium filix-femina", male fern, "Dryopteris filix-mas", and hard shield-fern, "Polystichum aculeatum". On more acid soils, sessile oak, "Quercus petraea", and birch, "Betula sp.", are dominant. The under-storey, of hazel, holly, "Ilex aquifolium", rowan, "Sorbus aucuparia", and hawthorn,
Sorbus domestica Sorbus domestica Sorbus domestica, with the common name service tree or sorb tree (because of its fruit), is a species of "Sorbus" native to western, central and southern Europe, northwest Africa (Atlas Mountains), and southwest Asia (east to the Caucasus). It may be called true service tree, to distinguish it from wild service tree "Sorbus torminalis". It is a deciduous tree growing to 15–20 m (rarely to 30 m) tall with a trunk up to 1 m diameter, though it can also be a shrub 2–3 m tall on exposed sites. The bark is brown, smooth on young trees, becoming