FOLIAGE EFFICIENCY OF FOREST-FORMING SPECIES IN THE CLIMATIC GRADIENTS OF EURASIA
V. A. Usoltsev1,2
1Botanical Garden, Russian Academy of Sciences, Ural Branch, 8 Marta str., 202a, Yekaterinburg, 620144 Russian Federation
2Ural State Forest Engineering University, Sibirskii trakt, 37, Yekaterinburg, 620100 Russian Federation
Keywords: чистая первичная продукция, продуктивность ассимиляционного аппарата, зимний видимый фотосинтез, транспирация, ассимиляция, дыхание, природная зональность, континентальность климата, net primary production, foliage efficiency, winter apparent photosynthesis, transpiration, assimilation, respiration, natural zoning, climate continentality
Abstract
The paperis of the scientific area of biogeography and devoted to a new aspect in the study of biological productivity of forest ecosystems on a geographical basis, expressed indirectly by climate parameters, namely, the foliage efficiency that until now is not investigated at the global level. Foliage efficiency is the ratio of net primary production (NPP) to foliage biomass and is expressed in relative units. Some features of change of foliage efficiency of vicarious forest-forming species in Eurasian transcontinental gradients are showed for the first time using the voluminous factual material. The set of published biomass and NPP data (t/ha) obtained in a number of 2192 plots is compiled. Using multiple regression analysis technique, the statistically significant changes in foliage efficiency values according to two transcontinental gradients, namely by zonal belts and continentality of climate, are stated for each forest-forming species. The species-specificity of age dynamics of stem volume and foliage efficiency is shown. It is monotonically decreased almost for all tree species in the following order: spruce and fir, pine, birch, oak, larch and aspen-poplar. When climate continentality increasing, foliage efficiency values of mature forests is dropping, most intensively in pines, less intensive in deciduous forests and virtually no changes in spruce-fir communities. In zonal gradient from the northern temperate to the subequatorial belt, foliage efficiency of deciduous species decreases, but it of the evergreen spruce and pine increases in the same direction. One of the possible causes of these opposite zonal trends of foliage efficiency in evergreen and deciduous species consists in different conditions of physiological processes in the year cycle, in particular, in year-round assimilates accumulation in the first and seasonal one in the second.
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