The productivity of oak stands in the Tsumanska Pushcha of Kivertsi National Natural Park

Abstract Today, the unique highly productive pine-oak and hornbeam-oak stands in Volynsk Polissia have been preserved in separate areas of the Tsumanska Pushcha Kivertsi National Nature Park (NNP) and need protection, regeneration and study of their condition and productivity at various stages of development. The objects of research were pine-oak and hornbeam-oak stands growing in different types of forests of the NNP. Forest management materials of the park for 2018 and typological analysis methodology were used for the study of the stands. The distribution of stands according to age classes and predominant species and stand density was carried. It was determined that productivity of stands with oak participation and forest typological potential in different types of forest is used by 82%–91%. In the wet and fresh hornbeam-oak-pine fairly fertile forest site type and wet hornbeam fairly fertile oak forest type the average actual volume of stands reaches the greatest value in the ninth age class (382, 350 and 309 m 3 ha −1 ). From the tenth age class and older there is a decrease of the average actual stand stock. Mature and overmature pine-oak stands of a wet fairly fertile site type are characterised by low productivity. As a result of non-observance of the formation and improvement felling rules of forests, secondary stands were formed in the NNP. The share of secondary stands in the most widespread forest types is 66%–78%. Pine, red oak, birch and alder dominate in the secondary stands. Spruce, aspen, hornbeam, ash, linden, larch and acacia grow in small forest areas. Secondary stands of hornbeam fertile oak forest type are formed by middle-aged red oak and fir. In order to increase the productivity and stability of stands with the participation of English oak in the conditions of the NNP, it is necessary to transform secondary stands into primary stands. The study of the features of the formation of the primary stands based on the principles of close to nature forestry is a prospect for further research.