Sustainable recruitment is necessary in uneven aged and inhomogeneous forest stands (selection forests, group plenter forests, continuous cover forests) to guarantee long-lasting structure. In protection forests, an abundant tree regeneration is of utmost importance. If the regeneration rate is small, the protection function will eventually be at risk. Today, adequate methods are missing that precisely estimate self-sustaining regeneration rates. Therefore, in this study the actual state of regenerating trees was assessed in monitoring plots at various altitudes. The results can be considered as generalised ranges of sustained regeneration rates. It was found that regeneration rates in selection forests at higher altitudes were lower than in more productive forests at lower altitudes. According to theoretical considerations, mortality in youth forests is dependent on height growth. It follows that mortality of regenerating trees in less productive, balanced selection forests is smaller than in more productive ones.