The Sonian forest, situated south of Brussels, is one of the last remnants of a vast forest that is believed to have covered the larger part of central Belgium up to at least the end of the Early Medieval period and which is mentioned as the silva carbonaria (Latin for ‘charcoal burners forest’) in several historical texts. The strict reserves within the forest, together with several other European old growth beech forests, were listed as a UNESCO world heritage site since 2017. Extensive archives allow us to reconstruct its history over the last 500 years, yet, little is known however on the extent, composition and exploitation of this forest before that time. We now present the preliminary results of an interdisciplinary study of archaeological remains of charcoal and metal production sites from this forest, which provide a lot of new information on its history and evolution. This study includes the detection of charcoal and metal production sites using LIDAR and geophysical methods, radiocarbon and OSL-dating of different types of features from these sites and anthracological analysis. In addition, the results also provide new information on the role of beech in the natural forest vegetation in the lowlands of NW-Europe.