GEOGRAPHICAL PATTERNS OF CHANGES IN THE BASIC DENSITY OF WOOD AND BARK OF FOREST-FORMING SPECIES OF EURASIA
Qualimetry of aboveground and underground biomass of trees is an integral part of studies of biological productivity and carbon depositing capacity of forest cover, necessary for the correct assessment of the carbon cycle in its spatial gradients and in relation to climate change. The great bulk of carbon is deposited in tree stems and largely depends on the basic density (BD) of wood and bark. The author's database on the qualimetry of forest-forming species of Northern Eurasia is used in the work. About 3.450 model trees of 9 tree species (genera) were selected from it. The constructed mixed-effects models describing the dependences of the BD of wood and bark on their dendrometric indicators, geographical coordinates and species belonging of trees, revealed a 0.25% decrease in the BD of wood by 1 ° N. in the direction from south to north and 0.26 % decrease by 1 °E. in the direction from west to east. In the same gradients, the decrease in the BD of the stem bark is 0.55 % by 1 °N. and 0.28 % by 1 °E., respectively. The largest share of the explained variability of BD is accounted for by the species of trees - 74 % for wood and 87 % for bark, significantly less - by geographical location - 12 and 9 %, respectively, and the smallest share - by dendrometric indicators of trees 14 and 4 %, respectively. The ranking of species of equal-sized trees by BD value was performed, which showed that each species has a specific ratio of BD of wood and bark. This means that for a more correct assessment of the basic density and carbon deposition in wood and bark, it is necessary to process separately wood and bark of the disks removed from stems, and not the disks over bark as a whole.