RANK DISTRIBUTION OF A TREE PHYTOMASS FRACTIONS IN NEW INTERPRETATION
V. A. Usoltsev1,2, I. S. Tsepordey1
1Botanical Garden, Russian Academy of Sciences, Ural Branch, Yekaterinburg, Russian Federation
2Ural State Forest Engineering University, Yekaterinburg, Russian Federation
Keywords: Pinus L, P. sibirica Du Tour, P. koraiensis Siebold & Zucc, Abies Mill, Picea A. Dietr, Larix Mill, Cryptomeria D. Don, theories of assimilate distribution in a tree, the Zipf-Pareto model, the coefficient of competition for a resource, the age change of the sign of the coefficient of competition for a resource
Abstract
Due to the observed climatic shifts, the problem of an adequate assessment of the carbon depositing capacity of forests and its possible climate-related changes is being actualized. To achieve optimal plant productivity, a certain proportionality between its constituent organs must be ensured, which depends, among other things, on the relative amount of biomass in these organs. In contrast to the theories of metabolic scaling and adaptive mass distribution, the study performed is associated with a concept based on non-Gaussian distributions. Using published data on biomass of 4515 trees of forest-forming coniferous genera of Eurasia, a new concept of ranking biomass fractions based on a modified Zipf-Pareto model is presented. Since the stem and branches of the tree perform the same function in its architectonics, namely, the implementation of xylem and phloem transport and the maintenance of the assimilation apparatus of the tree in the canopy space, we combine these two components into one common block when ranking biomasses. Since the 1-year-old seedling has no branches, and the needles are attached directly to its stem (the axis of the initial sprout), combining the biomasses of the stem and branches into a single block allowed us to consider the dynamics of the distribution of biomasses in the plant in the total age range, from seedlings to mature trees. Having accepted the ranking of biomasses in the sequence: stem plus branches, roots and needles, we established a positive relationship of the biomass with its rank at the initial stage of plant growth. As the plant grows, the named positive relationship changes its sign and becomes negative one. The presented regularity is confirmed statistically at the level of p<0.999. The change of the sign of the coefficient of competition for a resource occurs in all the genera in a fairly narrow age range between 2 and 7 years.
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