Structures of virgin and managed beech forests in Uholka (Ukraine) and Sihlwald (Switzerland): A comparative study

Based on an inventory of two permanent plots of 10 ha each, the main structural differences between a virgin beech forest in the Uholka-Massiv in Transcarpathia, Ukraine, and the Sihlwald, an - until recently - managed beech forest near Zurich, Switzerland, were analysed. In this paper, first results are presented and discussed. The diameter distribution of the Sihlwald showed the typical structure of a two-layered forest, whereas that of Uholka indicated a very uneven-aged structure with a more-or-less even distribution of trees over a large diameter range. Apart from the top height and the number of trees, which did not differ significantly between the two sites, all measured parameters such as basal area, standing volume and stand density index were higher in Uholka than in the Sihlwald. The volume of deadwood was about 14 times higher in the virgin than in the managed forest. Variability of most of the measured parameters between subplots of 0.25 ha was higher in Uholka than in the Sihlwald. Regeneration density is considered sufficient on both sites. Small-scale regeneration methods, such as progressive felling by small groups and single tree or group selection systems, "imitate" best the natural regeneration processes in undisturbed beech forests. The maintenance of a certain amount of admixed species needs silvicultural interventions as beech is very dominant on its optimum sites.