Broadleaved trees and shrubs are frequently scarce in upland forests in Britain, and national policy is to increase the proportion of broadleaves because of their value as wildlife habitat. Birches (Betula pubescens Ehrh. and Betula pendula Roth.) are between them adapted to succeed on a wide range of soils and are the commonest native trees of infertile regions. The value of birches for wildlife is high for most taxonomic groups. Birch woodland is capable of increasing the fertility of some mineral soils; it supports a large number of specialist and generalist phytophagous insects and a wide variety of woodland plants, birds and mammals. When mixed into conifer stands, birch is likely to increase their diversity considerably, especially for insects and birds.