Abstract: Modelling forest biomass sensitive to climate change is fulfilled at the levels as forest stands and single-trees, but mostly on a local or regional level, often without regard to the age, morphology of the forest stands and species composition. With this, it does not provide additive component composition, according to which the total of biomass components (stems, branches, needles, and roots), obtained by component equations, would be equal to the value of the biomass obtained by the general equation. The influence of climate change on the biomass of a tree species in the format of additive models for transcontinental hydrothermal gradients has not yet been studied. In the present study, the first attempt is made to model changes in the additive component composition of the stand biomass and NPP of two-needled pines along Trans-Eurasian hydrothermal gradients. In the process of modelling the database of pine stand biomass in a number of 2460 sample plots with the definitions of biomass and 760 plots with the definitions of biomass and annual NPP compiled by the authors, is used.
Keywords: Two-needled pines, biosphere role of forests, forest biomass, allometric model, biological productivity, additive biomass equations, mean January temperature, annual mean precipitation