This is woodland in which birch – whether silver birch Betula pendula, downy birch Betula pubescens or both – is dominant in the canopy. It occurs in places where the climate is too cold for oak Quercus spp. or ash Fraxinus excelsior to attain abundance or dominance. Other trees and shrubs can occur, especially rowan Sorbus aucuparia, aspen Populus tremula, hazel Corylus avellana, eared willow Salix aurita and juniper Juniperus communis. This woodland occurs on well-drained to rather poorly drained acidic soils in the Scottish Highlands and the Hebrides. The field layer is mostly grassy or heathy, but when very heavily grazed may be dominated by large bryophytes. Small herbs, bryophytes and ferns, including bracken Pteridium aquilinum, can be common, and on rocks, banks, trees and shrubs in the west there can be a rich flora of oceanic bryophytes including some uncommon species.