Modeling of the aboveground part of Scots pine trees components primary productions at the Eastern Polissya of Ukraine

Abstract

The net primary productions of the aboveground phytomass components (tree trunks and crowns) are estimated for Scots pine trees, which grow mainly in pure and mixed (admixture from 1 to 3 units) pine plantations of artificial origin of the Eastern Polissya of Ukraine. Plantations are characterized as highly productive (II, I, Ia and above classes of quality), medium and high-density stands whcih grow in fresh forests (A2), subors (B2) and sogruds (C2). 80 temporary test plots (TTP) used, which were planted in pine stands of Sumy (36 TTP) and Chernihiv (44 TTP) regions, where 900 model trees (MT) of Scots pine were cut down and measured, of which 226 MT with fractional assessment of aboveground phytomass components and 674 MT assessment of crown phytomass. Measurement of models and calculations of aboveground phytomass components of Scots pine trees net primary productions was performed using improved applicable methods and developed algorithm. The set of values of the experimental material in natural quantities is characterized by the normal distribution of values by age, diameter, and height of trees and relative density of stands. The closeness of the connection exists between all the studied indicators of model pine trees (from moderate; -0.31 0.91), weak (0.11 <r <0.30) - with the completeness of plantings and the share of current volume growth with indicators of phytomass components of tree crowns. Regression mathematical models calculated for estimating the absolute and relative current increment of trunk wood, trunk bark volume, wood mass, bark of branches and mass of needles in absolutely dry condition, in which the arguments are the age and diameter of trees, which characterized by coefficients of 0.72 to 0.92. In the model for the percentage of needles of the 1-st year of Scots pine, the relationship with the age of the trees is inverse and moderate, but significant at 5-level, the coefficient of determination of the obtained equation is 0.33. The developed normative tables of net primary trunk production of wood and net primary production of aboveground part of Scots pine trees showed that with the same diameter, with increasing age of trees – net primary trunk production increases only to a certain age, and reaching a maximum - decreases. With increasing diameter, at the same age - the net primary production of stem wood increases. The net primary production of the aboveground part of trees, as well as the individual components of the aboveground phytomass, increases with age and diameter. In typical forest vegetation conditions of the Eastern Polissya of Ukraine, a medieval tree (50 years old) of Scots pine in the aboveground part can accumulate 15.22 kg · year-1 of net primary production. The net primary production of Scots pine trunk, obtained according to research, is quite close to similar values determined by the current volume growth of pine trunks in the forests of Ukraine and Moldova.

Keywords

• temporary test plots
• model trees
• calculation algorithm
• current increment
• phytomass components
• mathematical models
• net primary products