The Vegetation in the Simen Mountains and Human Utilization of the Area

Abstract

The three main vegetation belts distinguished in the literature are founded largely on the general appearance of the vegetation, as given by the dominating species. These fit in the following manner into the topographical features of the area as in (Hedberg 1955; Cloudsley-Thompson 1969; Coe and Foster 1972; Lind and Morrison 1974): (1) The upland forest belt or montane forest covers in its natural state the topographically rich lowland with wide terraces, ridges and gorges below 3,000 to 3,100 m. Among the tree species we find Juniperus procera, Hagenia abyssinica,Olea chrysophylla, Syzygium guineense, Rapanea simensis. As can be seen in Table 11 (p. 71), where various differences of gradients of the slope, of the vegetation and human influence are shown, there is much human activity in this belt. Several villages are located on the terraces and, as a consequence, only small areas from the natural forest are left. (2) The ericaceous or moorland belt has its lower limit at about 2,900 to 3,200 m and its upper limit between 3,600 and 4,000 m, with 3,700 m as mean for the Simen highland (Hurni 1980a, in prep.). It thus dominates the main part of the escarpment and is therefore less influenced by human interactions. Main trees and shrubs are the tree heather Erica arborea, and St. John’s wort Hypericum revolutum (see Figs. 8, 9). In the lower section, among others Nuxia congesta and Rapanea simensis also join the heather belt. (3) The afroalpine belt consists of all the country above the timberline. This zone includes the higher terrain of the escarpment but extends mainly on the high plateau. It is characterised by grasses such as Festuca macrophylla, Festuca abyssinica, Danthonia subulata which are interspersed in some areas by Giant Lobelias Lobelia rhynchopetalum. At higher altitudes, the handsome but spiny shrub Helichrysum citrispinum is increasingly represented (see Figs. 2, 5, 6). In many parts of this belt, particularly in flat areas, domestic animals, mainly cows and sheep, are grazed quite extensively. However most eroded areas on the hilly plateau, such as the cultivated terrain around the village Gich are already located in the ericaceous belt (see Hurni 1978).