The availability of forest resources is directly affected by forest composition and structure changes that can regularly occur in the context of intensive silviculture and plantation of fast-growing tree species. Since 2000, the total area covered by Norway spruce plantations has decreased by an estimated 25% in Southern Belgium (Wallonia), which is especially worrying as they yield almost half of the total timber volume of the region. In order to predict the evolution of our forest resources, we first used aerial photographic interpretation to update the data of the permanent regional inventory and provide a more accurate assessment of the current resources of Wallonia. We then developed harmonized distance independent growth and management models for the three most planted softwood species of Wallonia : Norway spruce (Picea abies), Douglas-fir (Pseudotsuga menziensii) and larches (Larix sp.). These models were then implemented in a simulation software that can operate at a regional scale. This presentation introduces our methodology, the operating of our simulator, our current progress to adapt it for other stand structures and compositions and examples of carried out simulations.