Development of a cartographic mdel for the forest site types delineation in the Belgian Ardenne. The paper presents an original method dealing with the forest site types delineation. The suggested method consists in integrating a typological key in a GIS aiming at producing a thematic map that describes forest site types. Data used are the soil map of Belgium (digitized at the scale 1:20,000) and a digital elevation model built from a topographic map (scale 1:10,000). The typological key is mainly based on the methodology used by Thill et al. (1988) in the site types system for central Ardenne, the potential vegetation map of Sougnez and Dethioux (1975) and the ecoregion map of Delvaux and Galoux (1962). In that respect, site types are closely linked to the soil map and the phytosociological classification. So, they can be connected to the afforestation guide and different phytosociological and autecological studies concerning forest species. It is then possible to map the potential habitats or the site potentialities related to tree species. The key is valid for the Ardenne ecoregion located in Southern Belgium (elevation higher than 300 m). It has to be validated through an intensive use in the field, taking into account its imprecision linked to the types of collected data, chieffly those being digitized. The integration of such a tool in a SIG can be considered as an original way in terms of integrated forest management or forest sites description in the context of the project