THE CONJUGACY OF CLIMATIC INDICATORS IN THE LATITUDINAL GRADIENT OF EURASIA WHEN MODELING BIOMASS OF FOREST-FORMING SPECIES
I. S. Tsepordey1, V. A. Usoltsev1,2, D. V. Noritsin3
1Botanical Garden, Russian Academy of Sciences, Ural Branch, Yekaterinburg, Russian Federation
2Ural State Forest Engineering University, Yekaterinburg, Russian Federation
3Sberbank, Analytics Competence Center, Yekaterinburg, Russian Federation
Keywords: tree biomass, temperature and precipitation, forest-forming species, databases, multicollinearity of factors, variance inflation factor
Abstract
The carbon depositing capacity of forest cover in the context of climate stabilization is determined by the productivity of its biomass, which, in turn, is formed under the influence of climate. The first attempts to build maps of forest productivity by stem volume and its growth were based on integrated climate indices without the use of statistical methods. When the taxation indicators of stands and climatic factors were included in the models as independent variables, the contribution of climatic factors to the explanation of the variability of production indicators was statistically insignificant due to the regional level of the models. With the release of multifactorial modeling of biomass to the Eurasian level, the explanatory ability of both taxation and climate variables has become statistically significant. However, the stability of such models was not evaluated and the multicollinearity of the defining variables was not checked. In our study, on the basis of the author’s database on the biomass of trees of forest-forming species of Eurasia and the WorldClim climate database, a conjugate analysis of monthly and average annual precipitation for the period from 1970 to 2000 was performed, the relationship of aboveground biomass of trees with their size, precipitation and temperature was revealed, and the multicollinearity of independent variables in models of biomass of forest-forming species was estimated. It has been established that multicollinearity of determining factors, including temperatures and precipitation, is not observed in the range of the main forest-forming species growing in Northern Eurasia from the subarctic to the southern temperate zones when developing climate-sensitive biomass models. But south of the 37th parallel, in the subtropical, subequatorial and equatorial zones of Eurasia, multicollinearity of temperatures and precipitation occurs when modeling the biomass of trees.
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