Structural characteristics of Albanian beech (Fagus sylvatica L.) virgin forests -: Deductions for semi-natural forestry

The results of inventories of forest structure and tree regeneration in three Albanian beech (Fagus sylvatica L.) virgin forests are presented and discussed. The data reveal that these forests are characterized by high levels of (1) stand volume of living trees, (2) diameter differentiation and (3) density of saplings and young trees. Beech is the dominant tree species in the upper canopy layers as well as in the regeneration layer. The mean size of canopy gaps is smaller than the mean crown size of old trees. Therefore; gaps are formed mainly by the death of single trees. Subsequently, forest texture is characterized by small-scale changes in development phases. Giant trees, measuring more than 80 cm at breast height, are another prominent feature of the virgin forests examined. These trees show a clumped distribution with a tendency to randomness. Snags and downed logs above 20 cm in diameter amount to 36.3-85.3 m(3) /ha or 3.9-10.4% of the living stand above 7 cm DBH. Due to a high rate of decomposition, these values are low compared to other pristine forests of the temperate zone. Forestry can emulate patterns and processes of virgin beech forests by single - group tree cuttings instead of clear cut or homogenous shelterwood systems and a significant amount of old trees and coarse woody debris. Apparently, a high portion of admixed tree species is not a natural feature of beech forests. Therefore, a conflict could arise between the goals of enhancing tree species diversity and of emulating natural patterns.