Changes in foliage’s biomass of two-needled pine subgenus (Pinus spp.) and genus Betula spp. along the gradients of winter temperature and precipitation: inter-genera paradox in the forests of Eurasia

Abstract

Background The main pool of publications on this topic is related to the assessment of possible changes in vegetation growth under the influence of climate, but few of them actually took account the impacts of global change on species composition and morphological (taxational) structure, so led to an unanswered question, how the biological productivity of the forests will change if air temperature and/or precipitation change up to a certain extent. This is a subject of the study. Methods In this study, our database is used in a number of 2,110 sample plots for pine and 510 for birch. In each sample plot, the biomass of the forest stands was positioned in maps of January mean temperature isolines and to mean annual precipitation ones, and the input data matrix was compiled in which the values of biomass components and of stand taxation characteristics are mated with corresponding values of climate indices. The matrix was then subjected to regression analysis. Results It is stated, in cold and insufficiently moisture–rich climate zones, temperature increase causes a decrease in biomass of Pinus foliage, and in other regions its increase, but the Betula pattern is the opposite. With an increase in precipitation, the Pinus foliage biomass in warm zones increase, and in cold ones it decreases, but the Betula pattern is the opposite. Conclusion The biomass of pine and birch stands change in gradients of winter temperature and precipitation as propeller-formed but opposite patterns, which can be explained by the different winter physiology of evergreen and deciduous species.