EN
The main aim of our study was to verify the influence of climatic factors on the formation of abnormal 3-needle dwarf shoots in the two-needle Pinus mugo. Twenty individuals of the species, which had at least one abnormal brachyblast in 2002, have been studied in the Tatra Mountains (Carpathians) and an additional 20 in the Giant Mountains (Sudetes) over a period of 11 years. The number of atypical dwarf shoots in both populations in particular years was correlated to temperatures during the period of initiation and determination of apical meristems. Three-needle dwarf shoots appeared to occur every year in most of the studied individuals. It also showed positive correlation with (1) average, (2) absolute maximum, and (3) minimum average monthly temperatures of late autumn two years, and early winter one year, before emergence from the bud.