The thesis deals with sweet chestnut (Castanea sativa Mill.) as an important landscape-forming tree species, which is a valuable feature of the traditional agricultural landscape in the Modrý Kameň area. The aim of the research was to find out the current chestnut occurrence and its present state in the Modrý Kameň area based on detailed mapping. Biocultural value assessment of chestnut in the traditional landscape types in cadastral area of Stredné and Horné Plachtince. Evaluate the biological and morphological variability of chestnut flowers and nuts based on the occurrence of different stamen types of male flowers and the variability of nut size parameters. Mapping of chestnut trees was carried out in the cadastral areas of Modrý Kameň, Dolné Plachtince, Stredné Plachtince, Horné Plachtince, Dolné Príbelce and Horné Príbelce. 101 individuals and 123 groups (46 ha) of chestnut : (11 groups > 31 individuals, 10 groups 16 – 30 individuals, 34 groups 6 – 15 individuals, 68 groups 2 – 5 individuals) were identified and positioned in the field. Chestnut trees most frequently occurred in the extensively used CLC patches with pastures and with heterogeneous agricultural areas – “Land principally occupied by agriculture with significant areas of natural vegetation”, in parallel coinciding with HNV farmlands and Lowland hay meadows and with local occurrence of the protected bat species. Chestnuts found in the vicinity of old stables partially confirmed their specific function in cattle breading in the past. According to the achieved results, an extension of the current traditional agricultural landscape type of “pastoral land with meadows” was proposed in the study area. From obtained results was further revealed that at Modrý Kameň, Plachtince and Príbelce were statistically significant differences in the length of catkins in individual years. It was also found out that at Modrý Kameň, Plachtince and Príbelce were statistically significant differences in size parameters of nuts in individual years. Average nut shape index at three localities was 108.56 and dominated the triangular shape of nuts. The largest average lengths of catkins for all stamen types were identified in 2016. On the other hand, the largest size parameters of nuts (height, width, thickness) were measured in 2015.