Assessment of Woody Vegetation Structure in Relation to Different Grazing Areas and Chemical Composition of Major Browse Species in Chifra District, Afar Regional State

Abstract

The objectives of the study were to assess the woody species composition and chemical composition of major browse species under three grazing areas. The study was undertaken in Chifra district of zone one (Awsi Rasu) of the Afar Regional State. The total tree species recorded in the study district was 14. According to the perceptions of the pastoralists, of the identified woody species, 42.9, 28.6, 21.4 and 7.1% were highly palatable, palatable, less palatable and unpalatable, respectively. Some of the dominant (>20% of the density) and/or common (10% to 20% of the density) woody species in the communal grazing areas of the lower altitude (>550-850m) were Acalypha fruticosa and Solanum incanum. A long riversides species like Casuarina equisetifolia and Salvadora persiaca were dominant and/or common. Whereas, Acacia tortilis, C. equisetifolia, C. africana and G. tembensis were common and/or dominant in the enclosure areas.  A. fruticosa and G. tembensis were common and/or dominant in the communal grazing area of the upper altitude (>850-1100 m) The communal grazing areas had a higher percentage of woody vegetation in two consecutive height classes i.e. >0-0.5 m and >0.5-1m in the lower altitude (>550-850 m) but in the upper altitude (>850-1100 m) a higher percentage of woody vegetation were found in three consecutive height classes, i.e.,>1.5-2m, >2-3m and >3-4m than in the other two grazing areas. The CP content was higher in the composite sample taken from enclosure areas and lowest in riversides grazing areas in both seasons. Grewia tembensis was the best tree species with better nutritive value due to higher content of CP, whereas Balanite aegyptica was a low quality species relative to the other tree species.

Key words: Communal, riversides, enclosure, tree species, common and dominant