Cenopopulation structure of climax forest stands of formation of beech forests in Ukrainian Carpathians

Abstract

Logging in the mountainous conditions of the Carpathians has transformed the forest cover into a continuous succession system. Climax exemplary communities which are subject to protection and research according to the position of structure and dynamics on the population methodological basis, to have survived on an insignificant area in the reserves and protective categories of forests. The cenopopulation paradigm considers the edificator species (spruce, fir, beech, pine) as a system of interacting geographic, food and elementary populations. The structure of climax uneven-aged coenopopulations of formation of the beech forest is considered as natural climax cenoses that have arisen as a result of endo- or exogenous successions due to climatic and edaphic conditions. Their dynamic equilibrium is supported by the variability of the spatial mosaic structure through the age-old turnover of generations. The distribution of trees by diameter in climax forest stands is characterized by three types: reverse s-shaped, j-shaped and bell-shaped with right-sided asymmetry. The inverse s-type distribution type is the main one and occupies 77 % of trial plots. The types of reverse j-shaped and bell-shaped with right-side asymmetry are encountered respectively in 2 and 21 % of the trial plots. Vertical stratification in climax beech cenoses distinguishes four functional tiers-horizons, or spatial ecological niches. There is a possibility to forecast the directions of successions by species composition in tiers. In mixed dark-coniferous-beech stands, the beech occupies a dominant position, and fir, and especially spruce, a regressive position. The age structure of climax forest stands is presented to 6 age groups: pre-generative - juvenile and imature and virginal; generative – young, middle-aged, ripe and old (overmature). According to number of climax coniferous/beech and beech stands the full-member beech cenpopulations predominate. The age spectra of fir and spruce, maple-sycamore, ash, and elm are usually unequal, or fragmentary. On average, one hectare in climax coniferous/beech and beech stands include 174–235 individuals of generative generation – 42–52 – fir, 5–16 – spruce, 5–10 – maple-sycamore and ash tree. The timber stock in half (50–60 %) is concentrated in overmature and 25 % in mature age condition. Introduction of the population paradigm in forest synecology discover a new opportunity to divide the stand of the age generation and treat them as old-growth forests and virgin forests which form a set of key species of cenopopulations, and also determine the direction of succession.