An analysis of vegetation structure of the moist evergreen Afromontane forests of Ethiopia

Abstract

This study presents an analysis of vegetation structure of moist evergreen Afromontane forests of Ethiopia,namely Berhane-Kontir, Bonga, Harenna, Maji, and Yayu. A quadrats of 20 x 20 m were laid down alongtransects to collect vegetation data. Importance Value Index, vegetation profiles and species populationstructures were used to analyze the forest structure. The moist evergreen Afromontane forests of Ethiopiasupport a high density of woody plants, which, however, differs between sites. The highest density ofwoody plants was recorded in Yayu (69,130 individuals/ha) and the lowest in Harenna (9,309individuals/ha). Analysis of the diameter class distribution of some tree species, have exhibited abnormalpopulation distribution that might be related to the removal of some classes of trees either by natural orhuman-related factors. In the studied forests, the basal area per ha ranged from 46 to 54 m 2 in the order ofBerhane-Kontir > Maji > Harenna > Bonga > Yayu. In all forests, few species dominate the forest structure.Coffee is the only species with the highest relative frequency of occurrence in all forests. The verticalstructures of the studied forests are generally similar, i.e., 2-3 strata: emergent/upper stratum (> 30 m tall),middle tree stratum (15-30 m tall) and small trees and shrubs layer (2-15 m tall). The forest of Berhane-Kontir had the highest species richness based on growth form compared to the other forests. The studiedAfromontane rainforests revealed similar vegetation structures which could be attributed to similarhistorical events. Apparently, similar forest management schemes (e.g., thinning, harvesting level, etc.) canbe employed in all forests.