In virgin forest the biodiversity is maintained thanks to the natural disturbances that permit the coexistence of several species from different succession stages. On this basis, and to try to enhance vegetal diversity, the aim of this project is the study of the initial vegetation dynamics in hardwood forest gaps. On this purpose, the dispersal, the germination and the survival of hardwood species will be studied in different gaps of different size classes. Those gaps are the result of the december 1999 windtorm, in the Alsace region. In those gaps, several seed trap and quadrats will be installed, to focus on the natural regeneration of different tree species. Finally, the project will focalise on the vegetation community dynamics, in different plots in the gaps.