Structural research in the natural beech forest, situated at the eastern limit (Humosu Old Growth Beech Forest, Ia i county, Romania)

The paper points out the stability of the natural forest due to its structural complexity, reachedthrough milennia of evolution. The Humosu Old Growth Beech Forest” situated between 450-500m altitudein the Moldavian Plateau is a clear example of a natural structure with a continuous transformation given bythe passage through a series of stages (phases) with individual characteristics. Five of these individualphases are identified and described: the initial phase, the optimal phase, the terminal phase, the degradationphase and the regeneration phase. For each of these phases biometric characteristics are indicated, and thegeneral structural profile, as well. The distribution of dead wood volume inside these phases, as part of anatural matter circuit, found in different stages of degradation, shows the complexity of natural ecosystemsand their importance to life, in general.