Carbon Stock Potential of Gara Gola Natural Vegetation in East Hararghe Zone, Eastern Ethiopia

Abstract

This study was conducted at Gara Gola, in the Oromia regional state of Ethiopia, to examine the carbon sequestration potentials under three altitudinal gradients [i.e., Lower altitude (LA: 1500–1800 m.a.s.l.); Middle altitude (MA: 1801–2000 m.a.s.l.) and upper altitude (UA: 2001–2300 m.a.s.l.)]. A total of 60 quadrats of 20m x 20m, 5m x 5m, and 1m x 1m with six horizontal transect lines were employed to gather data on the tree, shrub, herbaceous, and soil, respectively. To estimate organic carbon percentage, soil parameters were collected from three soil profiles (i.e., 0 to 10 cm, 10 to 20 cm, and 20 to 30 cm). The mean total carbon stock of the study area was 641.18 Mg ha-1. MA had relatively higher TC than the other gradients. But the LA had the lowest TC stock, due to a high amount of human and animal interference. The results showed that the UA had significantly higher above-ground (AGC) and below-ground carbon (BGC) stocks with 147.3±39.4 Mg ha-1 and 18.37±7.8 Mg ha-1, respectively, compared to other gradients. However, LA had the lowest AGC (66.8±8.7 Mg ha-1) and BGC (12.06±2.6 Mg ha-1). Lower altitude exhibited a significantly higher SOC value than the other two altitudinal gradients followed by MA. The UA had the lowest SOC value. SOC across the three soil profiles follows a reduction trend from topsoil depth to lower soil depth with significant variation. In conclusion, LA should embrace better ecological, policy, and socioeconomic considerations than the other gradients.