SIZE STRUCTURE OF TREE PLANT-POPULATIONS - ITS PRINCIPAL TYPES, MECHANISMS OF FORMATION, AND USE IN THEORETICAL POPULATION ANALYSES

A theory allowing to describe and explain the process of formation of size structure of various tree plant populations is elaborated on the basis of synergetic approach. The structure in question is formed unde r influence of the processes of strictly determinated size growth and non-regular size differentiation. An equation is obtained to define th e form of a population size structure under stationary condition: n(x) = n0 x exp(-V(x)/B, where x is individual size, no is a constant, V(x ) = -A(x)d(x), A(x) is an expression describing determinated growth ra te of the size, and B is a parameter describing non-regular size diffe rentiation. The type of population size structure is determined first by the type of determinated size growth. Different size structures are studied by using growth functions most common in quantitative ecology , such as linear, J-shape, S-shape, Hompertz, and several modification s of the logistic curve. This is resulted in 7 types of tree plant pop ulation size structures covering all principal cases known from litera ture. A. correspondence between kinetic (growth) and statistical chara cteristics of populations is established for some of the most common t ypes of the size structure. Some macroscopic characteristical function s of population structure are introduced for systemic description of t he size structure, such as entropy, free and average growth energy. Th eir relation with fecundity is established. Two most frequent types of population structure described by exponential and normal distribution s of individual sizes are compared by means these characteristical fun ctions.