The permanent plots in Litschau were established in 1977. Since then every 5 years the 22 permanent plots in mixed Scots pine-Norway spruce stands in the Austrian part of the Bohemian Massif have been remeasured. Up to now, these permanent plot data was mainly used for the development and validation of growth simulators, but also for other scientific studies. The objective of this master thesis is to evaluate the collected data, to analyze if the diversity of the stands has an effect on the current total increment and how thinning intensity affects the dbh-increment of individual trees. To accomplish this task stand tables and structure-indices were calculated for each plot. Changes of structure in the permanent plots have developed as expected. Dominant height development in the old plots shows a sharp increase and dominant height curves of the young plots exhibit a much better site quality then the dominant height development of the respective yield tables. Reasons for the better growth could be wrong yield table assumption, advantageous weather conditions or improvement in site quality. The correlation between current total increment and diversity indices was analyzed, however,no significant correlation with any of the indices could be found. So either there is no correlation, or other factors affect the current total increment more than the diversity. At last the effects of different thinning intensities on individual trees were examined. A thinning experiment was established at the permanent plots in 1982. Individual trees were released from their competitors in a specific distance which was calculated according to Johann's 'A-value'. As a result, the maximum reaction appeared after 6 years, Norway spruce showed a higher increase in dbh growth than Scots pine and mature trees responded with a lower increase in dbh growth then younger trees. But despite all expectations, trees with the most severe release, responded with the lowest increase in dbh growth.