Some parameters of mesoclimates that determine altitude differentiation of forest formations on the Belyagush Ridge (South Ural Reserve)

The paper presents the results of studies of forest biogeocenoses on the Belyagush ridge. The analysis of materials was carried out in order to establish the boundaries of the high-altitude distribution of forest formations on the slopes of the Belyagush ridge, to determine the mesoclimatic parameters of ecotopes occupied by the formations, to clarify the presence and extent of temperature inversions. Forest test plots, the absolute heights of which were established, were used as markers of the height boundaries of the formations. Based on these data, the high-altitude strip of deciduous forests, marked with 7 test plots, occupies an altitude interval from 436 to 512 m above sea level, a strip of subnemoral broad-leaved-dark coniferous forests, marked with 10 test plots, occupies an altitude interval from 520 to 650 m on the western slope and an interval of 596–630 m above sea level on the eastern slope. The belt of ridge dark coniferous forests is marked with 1 trial plot located at an altitude of 830 m above sea level. The analyzed data of 4-year microclimatic observations indicate significant differences in the thermal regimes of ecotopes occupied by associations of deciduous and dark coniferous forests, comparable to latitudinal gradients. A comparative analysis of January amplitudes of the minimum daily temperatures on 3 sample plots located on an altitude profile extending from the Revet River valley through the middle part of the eastern slope to the top of the Belyagush ridge revealed frequent temperature inversions in winter. Over the observation period in January, inversions at the altitude segment of 470–605 m were observed from 14 to 24 days, on the segment 605–830 m – from 7 to 14 days, while the maximum positive vertical temperature gradients in these segments reached from +8,5°C/100 m to +8,9°C/100 m and from +1,3°C/100 m to +2,7°C/100 m.