Chornobrov O. Peculiarities of formation and ecological role of woody detritus in forest ecosystems of the Forest-Steppe of Ukraine

The research is devoted to the peculiarities of formation and ecological role of woody detritus (dead wood) in forest ecosystems of the Forest-Steppe zone of Ukraine. The typological diversity of forests of the Central and Eastern Forest-Steppe of Ukraine is analyzed. Ecological assessment of coarse woody detritus stocks was performed according to the State Forest Inventory data. Peculiarities of formation and ecological role of woody detritus in forest ecosystems on the territories of the nature reserve fund of the Central Forest-Steppe of Ukraine are investigated. The forests in the Central Forest-Steppe are represented by stands of 64 tree species. The main forest-forming tree species are Scots pine (Pinus sylvestris L.) (50.95%) and Common oak (Quercus robur L.) (18.08%). A total of 62 forest types were identified, among which fresh oak-pine subir (31.13%), fresh hornbeam dibrova (11.82%), fresh hornbeam-oak-pine sugrud (11.17%) predominate. In the Eastern Forest-Steppe, 17 forest types have been identified, among which fresh oak-pine subir (38.35%), fresh maple-linden dibrova (31.30%) and fresh linden-oak-pine sugrud (16.30%) predominate. In Central Forest-Steppe in Holosiivskyi National Nature Park (NNP) woody detritus was found in forest stands of 15 forest types on 68.0% of total forest area of NNP. Lying dead wood (61.9%) prevailed in comparison with the standing (38.1%). The volume of dead wood in forest stands was 1–50 m3∙ha–1, on average was 10.2 m3∙ha–1. Forest ecosystems of the Eastern Forest-Steppe on the example of Slobozhansky NNP is characterized by a predominance of standing dead wood (62.1%) compared to lying dead wood (37.9%). Woody detritus was found in forest stands of 11 forest types on 47.5% of total forest area of NNP. The volume of dead wood in forest stands where it was found was 5–50 m3∙ha–1, on average was 9.1 m3∙ha–1. In natural 130-year-old linden-ash-oak forests growing in wet dibrova conditions in the Vita river valley in Holosiivskyi NNP, the average dead wood volume was 94.2±9.8 m3∙ha–1 and is formed by two fractions – standing (25.4%) and lying detritus (74.6%), six tree species and all (I–V) classes of destruction. It is characterized by a variety of combinations of components, structural features, tree species and decay classes, which is inherent in forest ecosystems, which develop for a long time without human intervention. In natural 130–140-year-old forests dominated by Common hornbeam (Carpinus betulus L.) growing in fresh dibrova conditions in the Kaniv Nature Reserve the average volume woody detritus was 39.8±1.6 m3∙ha–1, consisted of dead trees (23.1%) and fallen dead wood (76.9%). It is formed by two tree species and is represented by I–V decomposition classes, but the volume is dominated by wood II (33.1%) and III (30.7%) classes.