It is assumed that people practiced woodland management, i.e. coppicing and pollarding, in Prehistory, but details are poorly known. Age/diameter analysis can help to get a better understanding of woodland exploitation through time in the wetland basin of the Ljubljansko barje, Slovenia, dating to 3700-2500 BCE. To do so, uncarbonized, waterlogged wood from 16 Eneolithic pile dwellings (Blatna Brezovica, Črešnja pri Bistri, Črnelnik, Črni graben, Dušanovo, Hočevarica, Maharski prekop, Parte, Parte-Iščica, Špica, Spodnje Mostišče, Stare Gmajne, Strojanova voda, Trebež, Veliki Otavnik, Založnica, arranged in alphabetical order), situated in two geographical clusters that cover a time span of c. 1300 years, were subjected to age/diameter analysis. It is the first time that age/diameter analysis is applied to multiple sites from the same region. The investigated posts represent a wide range of taxa, but oak (Quercus sp.) and ash (Fraxinus sp.) represent 75%, indicating selective use of wood for this purpose. Diameter selection of ash may have taken place as well.