The influence of anthropogenic load on the stands of coniferous and deciduous species in the conditions of the city of Ufa
Under the recreational influence, the growth of plantings in urbanized areas deteriorates. Thus, in cultures of 40-60 years, the radial growth of pine and larch, the mass, and the growth rate of pine needles decrease. The radial increase falls by 41-45 %, and becomes less than in the control, by 1.6-3.0 times. The difference in the length of pine needles according to the Student’s criterion relative to the control is significant only for healthy and weakened trees at the III and IV stages of digression. The degree of reduction in the weight of needles in healthy trees at the V stage of digression is characterized by 34 %, weakened - 31, severely weakened - 24 %. The vital state of linden trees in both alley and park plantings is reflected in the indicators of the assimilation and reproductive apparatus: in healthy trees, the average area of the leaf plate is 27.1 cm2, the number of flowers in the inflorescence is 9.8 pcs., the length of the stipule is 6.3 cm; in severely weakened trees - 20.1 cm2, 7.1 and 5.2 cm, respectively. Depending on the stage of recreational digression, the humus content in the soil decreases from 5.82 to 3.1 %. At the V stage of digression of forest areas, there is no horizon A0. With a decrease in the amount of humus in the soil in the upper horizons, the nitrogen content and the amount of absorbed bases change, which in the A1 horizon decreases from 35.4 (stage I of digression) to 30 mg-eq. (V stage of digression) per 100 g of soil. The same patterns in the presence of digression stages in the soil are characteristic of other soil elements. In horizons A1 and AB, the calcium content correlates with the stage of recreational digression (r = 0.94±0.06). An increase in the stock of grass cover phytomass contributes to the accumulation of potassium in the soil, the presence of K2O changes directly proportional to the dynamics of grass cover phytomass, P2O5 - inversely proportional.