Assessment of economic damage caused by negative impact of water on the raw material potential of forests on the coasts of Lake Baikal and the Irkutsk Reservoir

The purpose of the study is to analyze the current state of forest vegetation on the shores of the Irkutsk Reservoir and Lake Baikal, to calculate the direct economic damage as a result of possible direct losses of forests due to the negative impact of water on flooded and abrasion areas. The relevance of the study is determined by the need to minimize the damage to the coastal forests when water levels in the reservoirs change by introducing changes in the rules for the use of water resources, land use, forest management, etc. The main research methods were: geobotanical, forest taxation, geoinformation, expert, etc. The damage was determined in relation to the forest vegetation actually growing in 2022–2023, it is of a potential nature and does not reflect the damage from its death or damage in previous years. The calculation of damage was made in relation to wood resources, tree greens, bark, forest litter, mushrooms, berries, nuts, birch sap, medicinal plants, etc. To calculate it, standard payment rates per unit volume of forest resources were used. In turn, the determination of the volume of forest resources was based on indicators of biological productivity calculated using regional methods. The study made it possible to determine and map the distribution of forested areas within land categories and individual land uses, the qualitative characteristics of forests, and the economic damage by forest resource types at potential water rise levels. Among the municipalities, the highest values of economic damage were noted in the Irkutsk district due to the high taxation characteristics of forests, mostly located on the abrasion banks of the Irkutsk Reservoir. The quantitative parameters of the trend toward an increase in forest area and economic damage were determined depending on the increase in the absolute altitude of the terrain. This trend is especially pronounced for the coasts of the Irkutsk Reservoir, where from an altitude of 457.0 m to 457.85 cm, for every 10 cm of relief cross-section height, the forest area increases by 5603.1–7344.7 m², and the economic damage increases by RUB 85879.2–125512.1. For the shores of Lake Baikal, the trend of a steady increase in these indicators is disrupted after the 457.4 m mark, which is associated with the peculiarities of the geomorphological structure of the lake shores and the specific development of steppe (Olkhon region) and swampy forest vegetation complexes.