1. Department of Agronomy and Crop Science, Faculty of Agricultural and Environmental Sciences, University of Rostock, Rostock, Germany
2. Department of Natural Resources Management, College of Agriculture and Veterinary Medicine, Jimma University, Jimma, Ethiopia
3. Wondo Genet College of Forestry and Natural Resources, Hawassa University, Hawassa, Ethiopia
4. Forestry Research and Competence Center, Gotha, Germany