The aim of this bachelor thesis is to solve the varriability and growth characteristic of Black Alder in Lučenecká kotlina, specifically in Jelšovská pahorkatina. In the thesis is described the history, area of extention, systematic classification of taxon, characteristics of taxon and geographic variability. As well as economic importance of Black Alder stands and the harmful factors affecting it. Black Alder is used to stabilize river banks and also to the functioning of river ecosystems. With its properties positively impact on the environment in the immission areas. Moreover, in the thesis there are described geological, geomorphological, climatic, pedagogical and floristic condition. In the methodolical part is described detailed procedure for the establishment of research areas in the certain area and the collection of the material, the evaluation of the qualitative and quantitative features and the proposed methods of results processing.