STRUCTURAL AND DYNAMICAL STABILITY OF THE HARDWOOD TREE POPULATIONS

Stability of intact forest communities is provided by continuous succession of generation of tree species. Each new generation develops successfully only in the canopy gaps, which appear as a result of tree death. The gap size should increase as trees of new generation getting older. Gap sizes and age distributions in stable age spectra in populations are determined for different hardwood forest types in Russia and Ukraine. All age distributions are left-skewed, but tolerant and competitive species posses additional maxima corresponding to middle and old ages. Population stability may persist even if particular age groups are reduced in number or dropped out of age distribution. The tree population is under risk when the interval between generations is longer than the time needed for young trees to reach maturity.