Estimation of biomass and carbon sequestration capacity of the Surra mountain <scp>plantation forest</scp> in Gamo Highlands, Southern Ethiopia
Genesha Mada, Agena Anjulo, Abren Gelaw
Abstract
Abstract This study was aimed at estimating the carbon sequestration potential of the Surra planted forest on Gughe massive of the Gamo highlands in Southern Ethiopia based on tree species type. The plantation was established on degrading pasture land in the mid‐1980s during the golden era of plantation forest expansion history in Ethiopia. The Surra plantation forest was stratified upon three tree species namely E. globulus, C. lusitanica, and P. radiata. The data were collected from 32 sample plots (20 E. globulus, 10 C.lusitanica, and 2 P. radiata plots, each having 10 m*10 m in size), and were laid at random at the inner part of the plantation. The Species‐specific allometric equations and the pan‐tropical allometric model were used to estimate the aboveground biomass and carbon stock of the forest. The average “tree height,” “diameter at breast height,” and “tree stand density” per hectare were the highest for C. lusitanica and the lowest for E. globulus (except the wood density). The wood‐specific density/g/cm 3 was the largest for E. globulus. The average carbon sequestered in C. lusitanica (53.9 ton/ha) was significantly larger than E. globulus (35.6 ton/ha) and P. radiata (43.8 ton/ha). The estimated average carbon stock/ha of eucalyptus was the lowest due to its low stand density caused by illegal encroachment for construction, energy, and cash income purposes. The total dry biomass and carbon sequestrated are determined by area proportion; hence, eucalyptus covered an extensive area accounting for slightly less than two‐thirds of the total Surra plantation forest followed by Cupressus. The mean carbon stock (40.3 ton/ha) of the Surra plantation is lower compared with many plantation forest stock values under better management. The findings revealed that the significant variation in carbon stock with other forests despite the similarities in age, climate, location, and aspect was the result of encroachment, illegal cutting, frequent grazing, and limited protection, and call for policy attention from the Ethiopian government.