The diploma thesis deals with changes in the diameter of logs of Scots pine (Pinus sylvestris),originating from russian-ukrainian and Slovak provenance and their response to climatic factors like as air temperature, global radiation, precipitation, relative humidity, soil water potential and water saturation deficit. The measurements took place on two research plots in Arborétum Borová hora (350 asl., 2nd forest vegetation stage), which belong to the components of the Technical University in Zvolen. DRL 26 dendrometers with automatic data recording were used to measure changes in perimeter. The data were recorded in the period from April to October, in the years 2018 a 2019. The years 2018 was. generally drier and warmer in comparison to year 2019. Air temperature and precipitation are factors that significantly influencing change in the circumference of the trunks, therefore in both investigated provenances the thickness increase in 2018 was smaller than in 2019. Russian – ukranian provenance responds more sensitively than Slovak to the influence of climatic factors.