Struktura a hustota dřevinné vegetace dvou lesních oblastí narodního státu Amhara, Etiopie

Abstract

This study was conducted in Jawi and East Belesa districts of the Amhara National Regional State in Ethiopia. It has an objective of describing the vegetation structure in relation to different environmental factors in general and Boswellia papyrifera, which is economically important species in particular. Vegetation data were collected in both sites (Mosebit and Hamusit) using plots of 50 m x 50 m (0.25 ha). In total 15 sample plots were set up. In each plot, all trees with DBH (Diameter at Breast Height), i.e. at 1.3 m above the ground were measured using caliper. In each major plot four subplots (4 m × 4 m) were established. Tree height measured using Hypsometer (Vertex III). Data’s on different environmental variables (slope, aspect and altitude) of each plot were also taken respectively using laser rangefinder Impulse 200 Standard, an electronic compass Map-Star Module II and GPS Juno™ ST handheld (Trimble, USA). A total of 58 woody species belonging to 22 families were identified from both sites. A total of 241 trees/ha and 292 trees/ha were found in Mosebit and Hamusit study sites, respectively. The seedling density result indicates 3656 seedlings/ha and 2469 seedlings/ha in Mosebit and Hamusit study areas, respectively. The density of Boswellia Papyrifera, which is economically important species were 140 and 127 tree/ha in Mosebit, and Hamusit study areas, respectively. The relative density of different tree species in different height and diameter classes were determined by altitude, aspect, and gradient of the study areas. The study result concludes that distribution of the species, relative density, height class and diameter class of species in the two sites is dependent on environmental factors. Finally, the findings indicate that the two woodlands harbor, economically important tree species. Therefore, giving due attention in conserving these wood lands is important from ecological, economical and conservation point of view.