Woody colonization on unmanaged urban and ex-industrial sites

Abstract

Forty-six unmanaged urban and ex-industrial sites in the county of Avon, South Staffordshire and the West Midlands were visited in 1992/93. The extent of woody colonization was very variable and despite an average stocking density of 1500 stems ha-1, only 19% of the land surveyed was colonized to an acceptable woodland standard. Woodland produced by natural colonization was species poor. Although there was variation between species, the presence of the parent was usually the most important factor associated with colonization. In general, colonizing plants were positively associated with subsoil, small stony substrates such as gravel and ballast, and a week grass sward.