A model named NBM was developed to judge quantitatively the risks of soil nutrient extraction due to timber harvesting in Switzerland. The model can be used for forest enterprises as well as for larger regions. It assesses nutrient extraction at the level of the single stand as part of a scenario analysis. The extraction of nine nutrients as a result of harvesting is quantified under conditions with different silvicultural and bucking methods. The results are then compared to the soil potentials and changes in these potentials. The simulation results are assessed with respect to sustainability. Two criteria are used to evaluate the long-term risk of nutrient deficiency. The validity of the model in a practical context is limited as more soil informations would be needed. The paper describes structure and functions of the model, its computational implementation, and the results obtained from its first application in the forest enterprise of Bremgarten, Wohlen, Waltenschwil. It ends with a critical analysis of this first implementation of the model.