STUDY OF MORPHOLOGICAL FEATURES AND FLUCTUATION ABILITY OF THE LEAF APPARATUS OF THE SILVER BIRCH
As a result of the increasing anthropogenic and technogenic impact on forest ecosystems, ecological monitoring over the changing indicators of growth and condition of trees has acquired a particular importance. Along with many traditional observation methods based on the analysis of water, soil and air samples, methods of bioindication of the assimilation apparatus have recently been used, which show the level of changes in the morphological characteristics of trees depending on the external negative impact of the environment. The purpose of the research is to determine the state of silver birch forest cultures in the green zone of a city of Nur-Sultan using bioindication methods. The object of research was the assimilation apparatus of 12-year-old silver birch forest cultures which at the age of 7 were transplanted from the strips to the spaces between strips. The morphological features and fluctuating asymmetry of the leaves were studied. The crops of silver birch were classified as weakened plantations with a coefficient of relative viability of 54.2-73.0%. In 2019, the average level of deviation from the norm corresponded to the crops transplanted at a low elevation and non-transplanted at a high elevation, a slight deviation from the norm was observed in trees transplanted at a higher elevation. In 2020, condition of silver birch plantings decreased to the 4th point of the asymmetry index. The deterioration of the condition of trees is associated with an increasing anthropogenic load on plantations and environmental pollution. Since the pressure of these negative factors on the environment will not decrease, but will only exponentially rise, it is proposed to start taking measures to increase the sustainability of plantings (thinning, use of fertilizers, and addition of growth stimulants, etc.).