Silvology is the general science of forest ecosystems, without the usual division between Man and Nature. This book aims to integrate and harmonize existing approaches. Topics covered include: Introduction of the methods; sections on forest organisms; a special chapter on trees; eco-units, ie forest ecosystems developing after some zero-event like fire, storm or waterlogging; silvatic mosaics built by the eco-units of different size, architecture and species composition; a summary of silvological rule determining systems behaviour at every level, eg fragmentation and fusion, transfer of functions, irreversibility and process oscillation.