# The Carbon Sequestration Potential of Degraded Agricultural Land in the Amhara Region of Ethiopia
## 1 Introduction  
Information on forest carbon dynamics, carbon stocks, and the sequestration potential of forests is increasingly necessary, as forests play a significant role in mitigating climate change. The highest proportion of terrestrial carbon is stored in forest ecosystems [1]. Thus forests are important to balance global carbon dioxide (CO\({}_{2}\)) [2; 3; 4]. Human activities are important considerations because land use change and forest management directly affect the forest conditions and thus the carbon cycle. In Ethiopia, population growth and investment followed by deforestation and land use change have led to a dramatic decline in forest land during the last decades [5; 6; 7]. Additionally, we see heavy disturbances in the remaining natural forests, such as cattle grazing or logging that result in severe soil degradation [8; 9; 10]. A study in the north-western highlands of Ethiopia revealed a decrease in natural forest cover from 27% in 1957 to 2% in 1982 and to 0.3% in 1995 [11]. The study also showsthat between 1957 and 1995 about 99% of the forest cover was mainly lost to land cultivation, with an increase of 77% in cultivated land. This depicts a huge loss of biomass and soil carbon following land use changes [9; 10; 12]. [PERSON] et al. [13] reported that land use changes may account for 33% of the total anthropogenic carbon emission between the years 1850 to 2000. A study by [PERSON] et al. [1] reported that about one petagram of carbon is emitted yearly due to tropical land-use change. Forest management may create a carbon sink through reforestation and rehabilitation of degraded land or may result in a carbon source due to overexploitation [14; 15; 16]. Studies on forest carbon stock under different management regimes have shown inconsistent findings. While some studies report a loss of carbon stock following management activities, others show no detectable differences between managed versus unmanaged forests. For example, [PERSON] et al. [4] compared conventional with intensive harvesting using 284 forest sites and found a 22% loss of carbon in the forest floor carbon following conventional harvesting. However, no significant differences were reported in the lower soil layers. [PERSON] [17] found no significant differences between three different forest management scenarios (unthinned, minor thinning, and heavy thinning) in both the forest floor and soil carbon. Certainly, the intensity and management type (ranging from light thinning to clear cut), as well as the thinning interval determines the impact on the carbon pools of forests [18]. Increasing the forest area and implementing sustainable forest management practices are important cost-effective options for climate change mitigation [19; 20]. Sustainable forest management helps to sequester carbon and provides timber and fuelwood, a renewable energy source. The Intergovernmental Panel on Climate Change (IPCC) identifies three types of climate mitigation options in the forestry sector, namely afforestation, reforestation, and reducing/avoiding deforestation [21]. This suggests activities for reducing emissions from land use change, as it is included in the climate mitigation objectives of the United Nations Framework Convention on Climate Change (UNFCCC) [22]. At the UNFCCC 2005 meeting, this topic was negotiated and activities were put forward that are known under the term REDD (REDD-Reducing Emissions from Deforestation and forest Degradation) and REDD+, the latter of which explicitly adds the role of sustainable forest management and its role for carbon management in developing countries. REDD+ has gained enormous attention in many developing countries, including Ethiopia since it is also seen as a financial mechanism to improve the environmental conditions by avoiding deforestation and promoting reforestation/afforestation programs [23]. The implementation of REDD+ will also lead to social and environmental benefits by providing timber for various purposes and supports biodiversity conservation [24].