Thirty-Year Dynamics of the Pine Stand Sanitary Conditions of Boyarka Forestry Research Station

The drying up of coniferous forests is a problem for both Europe and Ukraine, where drying area of pine stands covered the Polissia region and spread to other natural areas, therefore, the analysis of pathological factors of the reasons for the weakening and deterioration of the sanitary condition is relevant. The purpose of the study provides for generalisation of the reasons for the deterioration of the sanitary condition of pine stands and pathological processes in dynamics over 30 years. The results are based on data from 12 permanent and 10 temporary sample plots established in a separate subdivision of the National University of Life and Environmental Sciences of Ukraine “Boyarka Forestry Research Station”. The study used empirical and systematic methods. The predominance of drying of pine stands due to infection with the pathogen Heterobasidion annosum ((F.) Bref.) was revealed, at the same time, with the highest infestation coefficient, the dominant species in the stands under study were ash bark beetles Tomicus piniperda L. (54%), Tomicus minor Hartig (46%) with high and medium infestation rates and Monochamus galloprovincialis Olivier with a tree population ratio of 52% and an average degree of population in trunk areas with transitional and rough bark. In the dynamics of observations since 2011, an increase in the index of sanitary condition of pine stands and deterioration of forests due to changes in weather conditions and climate aridity have been established. After the dry growing seasons of 2015-2017, the drying of pine trees with mass reproduction of stem pests was revealed, the infestation coefficient of which indicates the dominance of the sharp-dentated bark beetle Ips acuminatus Gyll. and a large ash bark beetle Tomicus minor which are aggressive species. Since 2019, there has been a decrease in the number of bark beetles due to exceeding the long-term precipitation rate due to a decrease in the temperature at the beginning of the growing season and unfavourable weather conditions for wintering of these insect species. The results obtained would become an informational component in the development of a strategy for managing damaged forest areas