Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: DIVERSITY AND STANDING CARBON STOCKS OF NATIVE AGROFORESTRY TREES IN WENAGO DISTRICT, ETHIOPIA
by Talemos Seta and Sebsebe Demissew

Abstract:
Agroforestry systems in the tropics have high potential for carbon sequestration particularly under a changing environment. Species diversity, richness, similarity index and standing aboveground biomass and carbon stocks of canopy trees were assessed in wenago district (Gedeo zone), Ethiopia. A total of 20 agroforests were surveyed through a stratified random sampling method within four PAs (Peasant Associations, a lowest administrative unit). A sampling plot of 900 m2 was used in each agroforest for plant data (trees with DBH ? 15 cm) collection on plant names, height, basal area and DBH. Shannon-Wiener diversity (H') and Sorensen�s similarity indices were used to compute species diversity and species composition among PAs respectively. Aboveground carbon stocks of trees were computed using allometric relationships, assuming C as 50% of biomass. A total of 24 tree species comprised under 24 genera and 19 families were identified. Of 24 agroforestry tree species identified, 53.52% (13 plant species) are found common in four PAs. The H' of the agroforests was 2.43 with the evenness of 0.84. With regard to density-DBH distribution, the result showed that the highest stem density (564.4 individuals ha-1) was recorded in the 40-60 cm range with the overall average stem density of 492.22 h-1. The total value of all study sites have the AGB of 37.31 t ha-1. The AGB have shown the trend that the density of trees and DBH classes have weak correlation with standing AGB ( R2 = 25%, P = 0.001) and relatively strong correlations (R2 = 64%, P=0.001) between species richness and aboveground biomass. The highest AGB (15.8 t ha-1) was recorded in the DBH range of 80-100 cm followed by 7.37 t ha-1in the DBH of 40-60 cm. The study shows that agroforestry trees have great potential for carbon storage and thus may reduce pressure on adjacent natural forest, opening potential opportunities of payments for avoided deforestation and forest degradation. Thus, responsible bodies should give strong emphasis for the management and sustainable use of agroforestry trees and the role of agroforestry system for climate change mitigation strategies.

Keywords: aboveground biomass, agroforestry system, carbon stock, species richness, species diversity,

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