Book excerpt: One of the central research themes in ecology is evaluating the extent to which biological richness is necessary to sustain the Earth's system and the functioning of individual ecosystems. In this volume, for the first time, the relationship between biodiversity and ecosystem processes in forests is thoroughly explored. The text examines the multiple effects of tree diversity on productivity and growth, biogeochemical cycles, animals, pests, and disturbances. Further, the importance of diversity at different scales, ranging from stand management to global issues, is considered. The authors provide both extensive reviews of the existing literature and own datasets. The volume is ideally suited for researchers and practitioners involved in ecosystem management and the sustainable use of forest resources.