The bachelor thesis is focused on the evaluation of changes in the trunk circumference and growth of forest beech (Fagus sylvatica L.) in the 3rd altitudinal forest zone in 2019 in relation to meteorological conditions and soil moisture. An experimental stand with 12 individuals of beech was established at the Bienska dolina locality, on which measurements of changes in the circumference of the trunks were performed using dendrometers. Meteorological parameters were obtained from a digital meteorological station, which was built near the experimental stand. These meteorological parameters were shown to influence the change in beech perimeter. The highest rate of increase was from mid-May to mid-June, when mainly temperatures and favourable values of soil water potential caused the strains to achieve an increase of 6 mm in diameter, which represents 71% of the total annual increase. In July and August, due to the lack of precipitation and the influence of meteorological factors, drought stress and subsequent shrinkage of the strains occurred. The most significant shrinkage of the trunk was visible from the beginning to the end of July, where the trunks reduced the circumference by 0.5 mm on average and the values of siol water potential reached the measurement limit, up to -14.4 bar. Than, due to atmospheric precipitation, the value of soil water potential increased and the circumference growth had a slightly increasing trend where the final value reached an average of about 8.5 mm in 2019. To plot and compare the daily courses of changes in the perimeter, we chose two periods, namely the period with sufficient water in the soil and the period with water deficit in the soil. Based on this we can evaluate that in the period with sufficient water in the soil (with a favourable value of the water potential of the soil), the expansion of the strain occurred mainly in the evening and at night. On the contrary, during the period of drought stress, no increase was formed and the trunks gradually shrunk, mainly during the day due to high temperatures and global radiation and at the same time a significant reduction in the water potential of the soil.