The present study aims at conception of a site classification wich contains most of the usefull information for forest integrated management. It has been applied to humid forests of Wallonia, specially related to black alder, indigenous tree of those sites, but slightly known and under-valorized. After the presentation of some ecological and silvicultural aspects of black alder related in the litterature, we proceed to review site classification, productivity estimation and site productivity evaluation methods. Then, we relate the ecological caracterization of the 166 alder sites of the sampling, with humid sites specific variables, espacially in relation to the phreatic water. Those descriptions allow us to establish a site-classification of the humid forest sites with alder. In the same time, we proceed to the elaboration of site index curves, to the stands productivity estimation and to the analyse of the dominant girth evolution from dendrometric data collected on 106 of the alder sites. Those analysis allow us to evaluate the black alder sylvicultural potentialities. Using the results of the 2 studies, we analyse the site productivity in order to evaluate sylvicultural potentialities of each site type of the classification, and to contribue to the knowledge of alder autecology in Wallonia. In the last chapter, we develop a practical application for the humid forests of the Arden : the « site types catalogue » wich presents ecological fonctions, and sylvicultural potentialities for each site type. This constitue a modern tool of integrated management tacking account of all fonctions and services produced by the forest.