The influence of the accident at Chernobyl nuclear power plant on the condition of pine plantations of Ukrainian forests

Abstract The article analyzes the distribution of trees according to the main ecological indicators that characterize the viability of artificial pine stands, in which forestry activities were stopped due to significant radioactive contamination, 35 years after the accident at the Chernobyl nuclear power plant. In intensively polluted areas and control trial areas in fresh forests, the following distribution of trees by categories of sanitary condition was noted: healthy pine trees (category I) make up 29-33 percent and 47-53 percent of the total number of trees, respectively, weakened (category II) – 29-33% and 29-37%, very weakened (III category) – 13-17% and 6-12%, the share of dying and dead trees (IV-VI status categories) is 22-24% and 9-12%. It can be emphasized that in the same studied types of forest vegetation conditions, where the levels of radioactive pollution allowed to carry out forestry activities, a much better sanitary condition of pine stands was noted. Analyzing the indicators of the general index of the sanitary condition of pine plantations in the zone of unconditional resettlement, it can be noted that all stands belong to very weakened ones, the index is in the range from 2.45 to 2.55. In the control test areas, where forestry measures for the care of stands were carried out in a timely manner, this indicator was lower – by 13-26%. The study of the process of formation of waste and drying of pine stands shows that the share of trees of IV-VI categories of sanitary condition in fresh forests is 22-24%, and this is almost a third of trees that, as a rule, will die within a few years. In addition, trees of category III (13-17%) pose a significant threat, which will move into lower status categories without forest management measures. Research results show that after the cessation of forestry activities in the zone of unconditional resettlement, there is an intensive accumulation of dryness and a significant weakening of tree stands. In the radioactively contaminated territories, almost 58 to 70% of the trees are belonging to the II and III categories of technical suitability, and in the control areas the share of trees of the I category ranges from 45 to 64%.