Zeinalian A. Spruce forests decline in different site conditions of Gorgan (Ukrainian Carpathians)

The dissertation for earning the degree of Doctor of Philosophy (PhD) specialty 205 – Forestry. – Ukrainian National Forestry University, Lviv, 2022. In the research on the basis of complex forestry research for different Gorgan forest vegetation conditions: the evaluation of spruce forests durability and factors of their formation is given; high-altitude and forestry-taxonomic features of spruce forests decline and their impact on the structural changes of plantings and dynamics of formation of dead wood in them are highlighted; the forestry condition of such stands and the processes of natural regeneration in them are identified; the ideas of improving the management of spruce forests decline are given. In order to achieve the aim of the research – to quantify Gorgan’s spruce forests decline in different forest vegetation conditions and their forestry-taxonomic consequences, the generally accepted methods in forestry in three directions are used: 1) Analysis of scientific literature sources, data of climatic guides and materials of forest management relational base for identifying abiotic and forestry factors of durability formation and processes of spruce forests decline, their quantitative characteristics and territorial distribution. 2) Analysis of assignation materials of spruce forests decline areas to selective and continuous sanitary fellings in 2011-2019 on the altitude-forestry profile in the range of 350-1450 m above the sea level that covered Bohorodchanske, Maniavske, Hutianske Forestry of SE “Solotvunske Forestry”. The analysis included 362 decline areas with the description of their relief and soil conditions and forestry-taxonomic peculiarities of stands. At the same time on this profile the areas of root sponge in spruce trees were analyzed for 2019-2021 years and the damage indices of stands by the strongest windbreaker in recent decades in February 2020, as well as the marketability of timber destined for felling. 3) Conduction of forestry and taxonomic investigations on the trial areas to identify the dynamic changes in the structure of spruce forests decline, evaluation the accumulation of dry and dead lying wood, peculiarities of natural regeneration, state and damage of trees. The objects of the research were confined to the altitude profile in the range of 300-1175 m above the sea level with the natural change of forest types. The analysis of departmental materials showed that during the last decade on the foothills and in the mountainous conditions of Gorgan the process of spruce forests decline covered 13 % of the forest fund, with their greatest development in the lower mountain belt of beech and fir forests – over 18 %. The main areas of this phenomenon – 94 % are represented by the partial type and only about 6 % – by solid type. These processes are permanent with considerable variability from year to year. The areas of decline in 75 % of cases coincide with the areas of windbreaks and root rot, creating critical situations in the forests.