Наукові праці Лісівничої академії наук України (Dec 2019)
Live biomass production of the aboveground parts of black locust stands in forest plantations of the Northern Steppe of Ukraine
Abstract
The ecological potential of forest ecosystems can be estimated solely on the knowledge basis of their biological productivity. Increasing aboveground live biomass of forest plant community leads to a more intensive sequestration of carbon dioxide, which is one of the effective mechanisms for countering climate change. The mean annual increment of wood in the forests of the State Forestry Resource Agency of Ukraine is 3.9 m3 ha-1, ranging from 5.0 m3 · ha-1 in the Karpathians to 2.5 m3 · ha-1 in the Steppe zone. One of the most common tree species of forest stands of the Northern Steppe is black locust. In the forests of Dnipropetrovsk regional forestry and hunting administration, this forest-forming species occupies an area of 19683.7 ha. The current volume of stem wood and production of live biomass components of aboveground parts of black locust stands in Ukraine are determined for modal stands, which are characterized by the following biometric indices: age – 3-82 years, trunk diameter at breast height – 3.9-24.8 cm, height – 5.2-21.5 m, relative stocking – 0.1-1.15. As input arguments of the regression equations we have used biometric indices of black locust stands. The developed regression allometric models for estimating the current volume increase by stock, live biomass of wood and bark of trunk, live biomass of crown components – wood and bark of branches, live biomass of foliage have equation determination coefficients (0.24-0.96) that exceed the critical values. The five-factor model is identified as the most statistically significant, which includes age, mean diameter, mean height of the main species, growing stock and relative density of stands as arguments. Calculation of stem wood production of black locust stands was carried out through assessing their current growth by stock and the mean basics density of stem wood which is 499.8 kg (m3)-1. The reference materials for assessing stem wood production of stands are given within the range of mean diameter of a stand from 4 to 28 cm and for stock of stem wood – from 20 to 180 m3 ∙ ha-1. The production of stem wood decreases with an increase of mean diameter of a stand. At the same time an increase of growing stock leads to an increase of production, provided that the diameter does not change. In the age structure of black locust plantations in the Northern Steppe, a group of over mature stands is dominating, for which, in the range of mean diameters of 14-24 cm, stem wood production is 1.73-2.69 t ha-1 year-1. The total live biomass production of aboveground part of black locust stands of forestry enterprises subordinated to the State Forest Resources Agency of Ukraine in the Dnipropetrovsk region is estimated at 138.3 thou. t·year-1.
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