Identification of virgin and quasi-virgin forests in the Uzhanskyi National Nature Park

Background. Modern anthropogenic activities have significantly contributed to the decrease of primeval, quasi-primeval, and old-growth forests worldwide and in Europe in particular, leading to catastrophic changes. Such forests are key reservoirs of floral and faunal diversity and play a crucial role in climate regulation. This study is dedicated to the conservation of biodiversity in forest ecosystems of the Carpathian region of Ukraine through the identification of primeval and quasi-primeval forests within the Kostryna Nature Conservation and Research Department (NCRD) of the Uzhanskyi National Nature Park in Zakarpattia Oblast (Ukraine). Materials and Methods. The affiliation of specific natural forest tracts in the Carpathians was determined based on desk and field research. Results. The most significant forest areas were found to be natural habitats of Fagus sylvatica L. stands with admixtures of Quercus petraea L., Acer pseudoplatanus L., Ulmus glabra Huds., and Carpinus betulus L. It was found that the species composition of admixtures in beech forests is significantly influenced by vertical zonation and associated soil conditions. On the southern peaks and slopes of Mount Knyahynitsa, within the altitudes of 400–600 m above sea level, the presence of pure beech forests was noted, which is associated with optimally favorable climatic and soil conditions for the growth and deve­lopment of endemic species. Conclusions. Within the studied areas (Domashinsky Verkh Mountain and Knyagynitsa Mountain), 36 inventory points of primeval forest systems were identified, totaling 1,075 ha, along with 3 quasi-primeval ecosystems, each covering 8.6 ha. The need to designate them separately is indicated by the exclusively natural origin of old-growth (156–196 years) stands of F. sylvatica, Q. petraea, C. betulus, A. pseudoplatanus, and U. glabra. These primeval and quasi-primeval forest ecosystems are characterized by complex horizontal and vertical structures with the presence of three and four layers. The studied forest ecosystems belong to the first site quality class, highlighting their ecological importance for biodiversity conservation, soil erosion prevention, soil environment restoration, and maintaining ecological balance.