Bioecological and energy potential of Robinia pseudoacacia L. stands under the conditions of the Vinnytsia Forestry District of SE «Forests of Ukraine»

Abstract

The scientific work presents the results of a comprehensive study of the productivity and ecological role of Robinia pseudoacacia L. plantations in Vinnytsia region. The relevance of the study stems from the widespread use of this species in agroforestry, energy forestry, and the reclamation of degraded lands, due to its high ecological plasticity, ability to fix atmospheric nitrogen, and rapid biomass growth. A review of the literature demonstrates the ambivalent impact of Robinia pseudoacacia L.: on the one hand, it improves soil fertility and increases nitrogen content; on the other hand, it poses a risk of displacing native plant species and disrupting the hydrological regime of the area. Fifteen temporary test plots with a total area of 5.25 hectares were established within the Vinnytsia Forestry Branch. Plot selection was carried out based on forest site conditions, stand age, species composition, site quality, and sanitary condition. The data collection methodology followed the national standard SOU 02.02-37-476:2006, ensuring the representativeness and reliability of the obtained data. The results of the study indicate the high biological productivity of Robinia pseudoacacia plantations within the Vinnytsia Forestry District. The predominant forest site conditions were fresh loams (type C2), which provided optimal conditions for the growth of this species. The age structure of the plantations is characterized by the dominance of young and middle-aged stands (over 56%), indicating active regeneration dynamics. Maturing, mature, and overmature stands accounted for a smaller proportion, reflecting effective forest management practices. The silvicultural and mensurational characteristics revealed significant variability in stand parameters depending on age. The average tree diameter ranged from 3.7 cm in 4-year-old stands to over 27 cm in 82-year-old stands, while tree height varied from 4.2 to 24.5 m. Absolute stand density ranged from 1.24 to 44.71 m²/ha, and relative density from 0.22 to 1.09, indicating different developmental stages and stand densities. Owing to the high wood density and calorific value, the stands exhibit considerable potential for biomass production as a source of renewable energy. The assessment of phytomass across different fractions of the aboveground tree components enabled an objective estimation of accumulated biomass per unit area and the calculation of potential energy yields. Structural analysis of sample plots by site quality classes revealed a predominance of medium-quality stands (classes I and III), characterized by an optimal balance between growth and ecosystem stability. This creates promising prospects for the further use of Robinia pseudoacacia L. in regional forestry practices as a key tool for bioenergy development and forest reclamation of degraded lands