Carbon Storage and Climate Change Mitigation Potential of the Forests of the Simien Mountains National Park, Ethiopia

Abstract

The study assessed land cover change, carbon stock and sequestration potential of Simien Mountains National Park (SMNP), Ethiopia. Landscape was stratified into four zones based on the vegetation ecology and land uses: Afro-alpine grassland (AAGL), Afro-alpine woodland (AAWL), Afro-montane forest (AMF) and Cultivated and overgrazed land (COL). 40 sample plots were taken randomly (10 from each zone). Nested plot design with size of 50m*50m and subplots of 20m*20m, 10m*10m, 5m*5m, 2m*2m and 1m*1m was used for the measurement of trees of different diameter classes. Soil sampling was done at the four corners of the 10m*10m subplots to a depth of 30cm and taken to laboratory for analysis along with litter and undergrowth. Allometric equation was used for determination of above ground biomass (AGB) carbon. Below ground biomass (BGB) carbon was taken as 24% of AGB carbon. Land cover change was analyzed comparing satellite images of different periods. It was found that the COL has increased from 20% in 1972 to 48% in 2013. As a result, the AMF and AAWL have shrunk by nearly 50%. A future projection with a simple linear model indicated 73ha and 251.3ha of annual deforestation rate in the AAWL and AMF zones respectively, implying that it will take only 71 and 49 years for the AMF and AAWL respectively to be completely lost. Above ground carbon (AGC), below ground carbon (BGC) and soil organic carbon (SOC) holds 34.4%, 8.3% and 55.2% of the total carbon stock respectively. Dead wood and Litter Biomass together contributed only to the 2.2%. From land cover point of view AMF, AAGL, AAWL and COL stored 47.5%, 22%, 20.9% and 9.6% of the total carbon stock in the area respectively. A linear regression of Shannon diversity index against total carbon and AGC was calculated for AMF zone and as such no strong relationship was found for the total C (R2 = 0.242) and also AGC (R2 = 0.337), but it appeared that the stored carbon tends to decrease as the Shannon diversity index increases.