Rapidly decreasing agro-sylvi-pastoral activities are one of the most important concerns of forest management in southern Europe regarding biodiversity conservation. The aim of this study is to explain the relationships between sylvicultural activities and plant biodiversity patterns. The study area is located on the northern slopes of the Lure mountain (550-1,700m a.s.l.) in the Southern French Alps. Plant biodiversity was assessed using 400 m2 floristic relevés randomly chosen within three major forest stand types: black pine (Pinus nigra), beech (Fagus sylvatica), and European silver-fir (Abies alba). Their distribution was compared to environment and forest management variables. Vascular plant richness was used as a surrogate of biodiversity. The different stand type had demonstrated different biodiversity patterns. Although black pine stands had the highest mean plant biodiversity, the highest forest plant and ancient forest plant biodiversity was found under the canopy of silver firs. Environmental factors affecting biodiversity were also variable depending on stand type. We thus suggest that the dominant tree elements within each stand should be taken into consideration when management methods aim at achieving the highest vascular plants diversity. For black pine, specific richness can be maximized by making early and regular thinnings avoiding sudden clearing of the forest and by applying several shelterwood cuttings. For beech, total canopy cover should be diminished by making early thinnings, creating openings and shelterwood cuttings within the densest stands. Finally, for silver fir, the current practice of letting stands evolve naturally is sufficient for maximizing plant biodiversity if openings created by old tree mortality are maintained