Live biomass production in Common oak stands of Ukrainian Polissia

Abstract

Within this research article we have analyzed mensurational characteristics of common oak stands in Ukrainian Polissia. We have also shown distribution of total and mean growing stock of the oak stands by age classes. Based on the developed reference materials for assessment of bioproductivity of oak stands in Ukrainian Polissia, we have analyzed dynamics of stands’ production within site index classes. We have calculated productivity of the oak stands by live biomass components and production by age classes and administrative regions. Also, here we present a fraction-wise distribution of growing stock of the oak stands by live biomass components and of total production – by administrative regions. The calculations were based on database “Stand-wise mensurational characteristics of forests” of IA “Ukrderzhlisproekt”, and database of temporary sample plots established in the oak stands. On this basis, reference materials for assessment of bioproductivity of common oak stands in Ukrainian Polissia have been developed. It has been found that in Zhytomyr region common oak stands have the greatest area share on the territory of Ukrainian Polissia (35,3%). Stands that have oak trees in composition, are characterized by age span from I to XX age classes, while area distribution is far from uniform. A great share of growing stock of these stands belongs to mid-aged ones, where stands are the most productive. Live biomass of aboveground components of the oak stands in Ukrainian Polissia reflects their age structure both by area and growing stock. Spatial variation of production accumulation by administrative regions is reasoned by differences in areas present. It has been established that over a half (55,3 %) of aboveground live biomass is contained in trunk wood, trunks’ bark and branches’ wood have the same percentage (11,9 %), branches’ bark accounts for 4,7 %, and tree greenery – 16,2 %. Assessment of dynamics of the oak stands’ production by site index classes has shown that its growth happens until the age of 35 years, and then it gradually declines. The highest bioproductivity is observed at age between 30 and 50 years, with minor site productivity-driven fluctuations. According to this research, total production of the oak stands is 324,7 thou. tons. Spatial variation by administrative regions is driven by presence of areas of the stands and their age structure. A larger amount of production is accumulated in common oak stands of Zhytomyr region (111,3 thou. tons), where a substantial part of production corresponds to mid-aged stands (78,2 thou. tons). The smallest amount of production is accumulated in the stands of Sumy region (7,5 thou. tons), in other regions its amount varies from 21,1 thou. tons (Kyiv region) to 59,7 thou. tons (Chernihiv region). It has been found that distribution of total production of common oak stands in Ukrainian Polissya by administrative regions and age classes reflects its dynamics by the reference data. Accumulation of production by young common oak stands (I-IV age classes) in Polissia zone is gradual and not intensive. Culmination of accumulation is observed in mid-aged stands (V-VIII age classes). Further, starting from immature group (IX age class), production of the oak stands gradually decreases with increase of their age. Variation of production of common oak stands in Ukrainian Polissia is mainly driven by occupied area, age of stands, and types of site conditions.

Keywords

• bioproduction potential
• dynamics of bioproductivity
• age structure
• mean growing stock
• live biomass components
• biomass expansion factors
• total increment
• ecological functions