There are many theoretical approaches to modelling forest systems, but not all of them have valid practical applications. This book reviews current thinking on various models and explores a variety of areas and approaches. The papers in this book have been selected and developed from those presented at a workshop held in Portugal in June 2002. The topics covered include: forest reality and modelling strategies; mathematical approaches and reasoning; estimation processes models; validation and decision under uncertainty and model archives and metadata.The book will be of significant interest to those in areas of forestry, applied ecology, and statistics and economics.