Structure and development patterns analysis of the Ostrya carpinifolia pure and mixed stands in the western part of Nestos valley

Abstract

The study was conducted in Ostrya carpinifolia (pure and mixed) stands in the slopes of the western part of Nestos valley (in the region of Xanthi). In order to analyze the structure and the development patterns of our stands, 41 plots were established, trees were cut, increment cores were taken, and stem analysis was conducted in 3 couples of dominant (competitive) trees. The main results of this research indicate that a) O. carpinifolia (pure and mixed) stands origin, initiation, development patterns, structure and spatial distribution were strongly affected by anthropogenic disturbances. b) The development patterns and structures (today) of O. carpinifolia structural types were also affected by three other important factors: the growth ecology of each species, their regeneration mechanisms and the quality of the site. c) O. carpinifolia and F. ornus trees, until the age of 80 - 100 years old, dominate in the upper storeys, exhibiting similar height growth patterns, whereas C. orienta lis trees usually are stratified in the lower storeys. d) The site sensitivity classification of the three main species, in O. carpinifolia mixed stands, is as follows O. carpinifolia > F. ornus > C. orientalis. This site sensitivity difference between the main species of our mixed stands has a significant effect in the formation of their structure. We observe a gradual alteration of the species contribution, in the total basal area of the stand, in relation to site quality. e) O. carpinifolia trees maintain a high sprouting capacity in medium ages (around 50 years old), whereas the most vigorous 30 years old stump sprouts, have high growth rhythms that are greater than those which had the seed origin standards in the first 30 years of their lives. f) The main silviculture objective is to convert almost all stands in seed origin stands. Furthermore, forest practice must favor multiple species mixed stands. Their composition must be determined in relation to site quality.