This volume summarizes the current knowledge on the exchange of trace gases between forests and the atmosphere with the restriction that exclusively carbon and nitrogen compounds are included. For this purpose the volume brings together and interconnects knowledge from different disciplines of biological and atmospheric sciences. It covers microbial and plant processes involved in the production and consumption of these trace gases; the exchange processes between forest soils and vegetation on the one hand, and the atmosphere on the other hand; the fate of the trace gases exchanged inside the atmosphere as well as environmental influences on the exchange of trace gases between forest ecosystems and the atmosphere. With this interdisciplinary approach the volume provides the background for an evaluation of the exchange of trace gases between forest ecosystems and the atmosphere and man-made disturbances of this exchange.