European beech (Fagus sylvatica L.) is one of the most important forest species in Bosnia and Herzegovina both economically and ecologically. Currently state of beech forests in the Republic of Srpska is satisfactory. European beech is not significantly affected by changing climate. However, taking into account different climate scenarios it is possible that increasing temperature and decreasing amount of precipitation will cause massive dieback of beech forests and reduction of diameter increment. For this reason it is necessary to conduct detailed dendrochronological research which will aim to explore the dynamics of the diameter increment of beech trees, response to climate and to prepare mitigation strategies that will be performed in the forests of the Republic of Srpska. In this study dendrochronological methods were used for analyzing the increment of beech forests in three stands which are at the lower limit, the optimum and the upper limit. Identified and analyzed were different reactions of beech trees in extremely dry years in three different forest stands.