Ukrainian plain oak forests and their natural regeneration

Changes in the areas and stock volumes of oak stands were analyzed within the six administrative regions in the plain area of Ukraine, based on forest management data (subcompartment database) as of 2001 and 2016. The studied regions geographically related to the Left-bank Forest-Steppe zone of Ukraine (Kyiv, Poltava, Sumy, Kharkiv, Cherkasy and Chernihiv Regions). The analyzed area was over 284,000 hectares. The paper outlines the present state of the oak stands, concerning their origin (vegetative, natural seed and planted seed stands). Forestry-taxation indices of the stands were determined by grouping the plots according to age and further clustering in four age groups. The natural regeneration under a canopy in oak stands was accounted and estimated using circular 10 m2 (R = 178 cm) accounting plots. The oak forests were found to be dominated by stands of vegetative (coppice) origin (57%). Planted seed-origin oak stands covered 101,000 ha or 36% of the total area (284,000 ha). Stands of natural seed origin amounted to 7%. From 2001 to 2016, the total area of oak forests in the study region decreased by nearly 7,000 hectares. The analysis of literature sources allowed identifying numerous factors, which have the greatest influence on the emergence, liveability, and growth of natural regeneration of pedunculated oak. Only 20% of the investigated oak stands were found to have a sufficient amount of oak regeneration. For the implementation of sustainable forest management, activities should be aimed at optimizing the age structure of oak forests and growing natural forests from seeds.