Silvicultural systems can be defined as continuous regimes of exogenous disturbances, characterised by the size of the final clear-cutting and the duration of the production cycle. The sampling scheme reiterates six silvicultural systems by three to five forests in Ardennes. Habitats and biodiversity are characterized at local and landscape scales by vascular plants, carabid beetles and nesting birds. The results point out the importance of the scales of disturbance and heterogeneity and of colonisation and competition processes. They are interpreted in terms of ecology and of sustainable forest management.