The diploma thesis deals with the problematics related with Black Alder (Alnus glutinosa L. Gaertn.) in chosen area of Biele Karpaty mts. Problematics describes the clasiffication of the taxon to the binomial nomenclature, natural distribution area, description of the species, noxious factors, and geographic and intraspecific variability. We established six plots and then we assessed quantitative features – thickness and height structure of the population, as well as qualitative features like origin, tree classes, intensity of embranchment, stem growth and course, stem surface, health condition of stems, health condition and shape of crowns, first level branch thickness, bark type and colour. After this evaluation we sorted the trees into qualitative classes. 56,1 % of studied individuals were mostly from the seed according to the origin. Individuals were usually represented in the main stand level 82,8 %, and with low embranchment – 57,2 %. Stems were in a good health condition, straight (53,3 %), and smoothly surfaced (84,5 %). We also assessed the egg shaped crowns and we considered it in good health condition – (more than 80 %). The general quality of the populations is positive because 78,9 % individuals was included in qualitative class A or B.