This book arises out of a symposium on forest and woodland terrestrial ecosystems which was held in Florence on 20-24th May 1991. It was organised jointly by the Commission of the European Communities (CEC) and the European Science Foundation (ESF) in association with the Italian Research Council (CNR). The symposium brQughUogether most -Of the internationally recognized groups working on forest ecosystems including biologists, botanists, ecologists, soil scientists, modellers, foresters and policy makers. All the CEC countries were represented. In addition, there was a broad audience from Eastern and Central Europe and from EFfA countries. Outstanding experts from outside Europe (US, Australia, Canada, Japan, China, etc.) were also present. In total, the symposium was attended by more than 500 participants. The structure of this book reflects the main elements of the meeting. As such it includes three main sections. The first consists of six major state-of-the-art reviews corresponding to the six plenary sessions, each followed by a discussion which has been summarized by rapporteurs. The reviews were prepared to assess critically the state of current knowledge in ecosystem research and to provide a scientific basis both for policy decisions and for further research.