It is established that different by age oak trees grow according to Ia -I b quality classes in stands. The small-leaved lime share in their composition varies within 2-8 units and lags behind oak in height by 10.0-46.1%. The sanitary index of oak varies in the range of 1.36-2.65. The total mass of physiologically active roots in the 60-cm soil layer is 11.82-20.71 kg ∙ (m2)-1. 64.5–86.0% of roots are concentrated in the upper 10-cm layer of soil. The total stock of forest litter in the stands was 0.28-1.34 kg ∙ (m2) -1 with a share of 22 leaves in its composition of 51.5-86.3%. Studies of soils' acidity have shown that stands mainly grow on very strongly acidic and strongly acidic soils. Soils close to the neutral reaction were formed in stands with a small-leaved lime share in their composition of 6-10 units. The correlation (r) of soil pH with the proportion of smallleaved lime in the stands is 0.88. It is shown that stands are characterized by significant variability with hydrolytic acidity of soils (2.10-10.66) and the amount of absorbed bases (3.00-14.13 mg-eq. (100 g)-1 of soil. In stands with a predominance of small-leaved lime in their composition, the value of hydrolytic acidity decreased. The correlation between the degree of saturation of the soil with absorbed bases and the proportion of small-leaved lime was direct and close (r = 0.74), and the hydrolytic acidity was close and inverse (r = -0.72). The amount of absorbed bases in the soil with a predominance of small-leaved lime in stands, or its significant representation in their composition, was characterized by an apparent growth of relatively pure oak stands or stands with a predominance of oak and hornbeam. It was found that the amount of easily hydrolyzed nitrogen in the upper 10-cm soil layer varies in the range of 9.8-28.0, and mobile phosphorus - 6.1-19.7 mg ∙ (100 g)-1 of soil. We have not observed the changes of these indicators by the number of small-leaved lime units in stands. The content of exchangeable potassium in the soil was relatively high and was 10.4-23.3 mg (100 g)-1 of soil. The humus concentration in the upper 10 cm soil layer varied from 1.79 to 6.35%. About 0.6-20.2% of incoming solar energy penetrates the canopy of the stand. It was found that under the tree canopy, the average daily air temperature decreased by 2.8-18.4%, and the level of humidity elevated by 2.6-41.4%. The impedance in small-leaved lime in the middle of the growing season was 5.0- 9.4 kOm, and the polarization capacity - 1.58-3.86 nF. In oak, those parameters were, respectively, varying in the range of 5.5-9.7 kOm and 1.92-2.73 nF. The intensity of the oak's vital processes in stands was determined to a greater extent by the excess of its height over other tree species rather than their share in stand composition. The average daily indicators of bioelectric potentials of oak trees in stands range from -43.0 to -102.4 mV, and in small-leaved lime, they are in the range of -58.6 - -116.5 mV. The excess of absolute BEP indicators of oak trees in mixed oak-small-leaved lime stands over pure oak stands was 9.6-129.6%. These parameters were the highest in forests, where oak exceeds small-leaved lime in height and diameter, and its share in their composition is 1-5 units. In small-leaved lime, where its share in stand composition is 5-6 units, the absolute average daily biopotentials exceed the value of pure small-leaved lime stand by 7.0-23.2%. The total amount of tree undergrowth varies from 1.13 to 10.27 thousand specimens ∙ ha-1 . It is represented by common and red oak, common ash, Norway maple and sycamore, elm, hornbeam, small-leaved lime, rowan, and European beech. The predominant number of plots is dominated by 1-3-year-old undergrowth. In 59% of stands, its share is 50-100%. Among the tree species, maple, sycamore, hornbeam and elm are best regenerated naturally. Their age in the stands reaches 4-8 years and older. Oak undergrowth occurs in 72.3% and small-leaved lime in 45.5% of the experimental plots. The number of small undergrowth is 50-100%. The stands are dominated by medium (41.1-54.1%) and very weakened (19.1-41.8%) undergrowth. The share of healthy undergrowth is 14.0-30.5%. The occurrence of undergrowth in stands varies between 30-95%. Natural seed regeneration of small-leaved lime (55-275 specimens ∙ ha-1) was detected in 38% of the surveyed 1-5-year-old fellings. It is shown that an increase in chlorophyll content by 16.9-49.2% and carotenoids by 16.9-49.2% is the adaptation of small-leaved lime undergrowth to the forest environment. This adaptive mechanism also includes increasing the ratio of chlorophyll a / b by 15.2-39, 1% and the amount of chlorophyll to the content of carotenoids - by 15.2-39.1%. It was proposed that to form the optimal composition of stands, at the age of maturity, it should have a density of at least 30-35 m2 ∙ ha-1 and include 6-7 units of oak, 1- 2 - hornbeam, 2-3 - small-leaved lime, as well as cherries
