The Swiss Federal Institute of Forestry Research has developed a data base for vegetation and plant communities based on the relational model. The logical data structures for this data base are described. All stored information is readily available. The data base facilitates phytosociological research in many ways. The data base contains the findings of releves conducted according to J. Braun-Blanquet. lt also includes information on the systematics of some 3500 flowering plants and ferns, 1200 mosses, and 300 lichens, as well as extensive data on ecology and site conditions. On completion the data base will include some 10,000 releves covering the whole of the Swiss forests, of which around 3000 have already (1985) been integrated.