The aim of this Masters thesis is the validation of the application of the MOSES model for the Sitka spruce (P. sitchensis). Furthermore, the study also aims to give a practical connection to the application of dynamic tree-growth models in forest management. MOSES (MOdelling Stand rESponse) is a potential growth-dependent tree-growth model developed at the University of Natural Resources and Applied Life Sciences, Vienna. The MOSES modelling approach is structurally based on statistically admitted models. Jonathan Dash (University of Wales) assessed the parameters for P. sitchensis in an international study (Tyfian Coed project at the University of Wales) in 2006. Now, the validation of the parameters for real-grown stands has been carried out. The validation was done by comparing the predicted and observed increment parameters. After validation, different management scenarios were generated to test common and new silvicultural arrangements for P. sitchensis. An important outcome was the virtual testing of new forest treatment strategies for the purpose of practical use. The main focus of the simulations was the comparison of various thinning and planting scenarios. Therefore, virtual stands with different basal area and real-grown stands were used for simulation scenarios.