State of in situ forest genetic resources of broadleaved tree species in the Right-Bank Forest-Steppe of Ukraine

Abstract Forest genetic resources (FGRs) are an important source of biodiversity conservation and forest restoration. Today, more than 600 genetic reserves (GRs) of more than 30 main forest tree species have been allocated in Ukraine. The main aim of the work is to reveal the features of the distribution, environmental condition and the trends of state of in situ gene sources of broadleaved tree species in the Right-Bank Forest-Steppe of Ukraine. Based on the research results, it has been established that the share of FGR in situ is only 0.3–0.5% of the total forest area of the region. The predominant species of forest stands of the region are English oak (Quercus robur L.) – 37.7%, European beach (Fagus sylvatica L.) – 26.8% and Common ash (Fraxinus excelsior L.) – 7.6%. The in situ locations of Black alder (Alnus incana L.), Sessile oak (Quercus petraea (Matt.) Liebl.), English oak and Common ash are characterized by the highest average annual temperature (8.1–8.2°С), the accumulated temperatures for the growing season (3111.9–3237.1°С). Stands with the European beech predominance are allocated in better moisture conditions by the precipitation-temperatures ratio (Selianinov Hydrothermal Index (HTI) – 1.769–1.802; climatic index by Vorobyov – 2.707–2.951). The in situ gene pool conservation units are defined by 12 soil types that are included in the 7 main groups according to the FAO international classification. The largest number of sites, 67 (56.8%), is concentrated on grey and dark-grey forest soils (Haplic Greyzems) (47%). According to the research results, GRs are not evenly distributed, they do not fully reflect the environmental diversity, and their area is negligible. We indicated the unsatisfactory condition of most genetic reserves. It was caused by reducing the share of main tree species, decrease in relative stocking density of stands and tree-breeding structure and deterioration of tree stands condition. This requires the development and implementation of an integration strategy based on the established concept of developing a national ecological network on both national and pan-European levels.