Instutute of Mathematical Problems of Biology of RAS
Institue of Physico-Chemical and Biological Problems in Soil Sciences of RAS
Centre for Forest Ecology and Productivity of RAS
Institute of North Industrial Ecology Problems of Kola Science Centre of RAS

Abstract. We have developed a system of plant functional groups for modeling dynamics of forest ground vegetation. Ecological and coenotic traits of species together with species life form and biomass values were used to classify species into the functional groups. Ground vegetation patches dominated by species of different plant functional groups were distinguished in the forest floor. We have characterized biomass of these patches by applying of statistical analysis of published data and results of our own field investigations combined into the database "Biomass". Biomass of vascular plants and bryophytes quite well differs between the patches. Variations of above and below ground biomass of vascular plants are minimal within the types of forest floor patches as compared to their variations within the plant functional groups and forest types. Database "Elements" on element concentrations of herbaceous species and cryptogams was also developed on the basis of results of field investigations in the North and the Middle Taiga. The functional groups of species well differ on the concentration of elements in plants forming a group. We have proposed a conceptual model of dynamics of ground forest vegetation; a model compatible with the individual-based EFIMOD model of forest growth and elements cycles in forest ecosystems. Spatial unit of the ground vegetation model is the same as spatial unit of the EFIMOD (0.5×0.5 м); it is a patch of the forest floor dominated by species from one or more functional groups.