1. Sustainability Research Institute, School of Earth and Environment; University of Leeds; Leeds LS2 9JT UK
2. Stockholm Environmental Institute; World Agroforestry Centre; United Nations Avenue, Gigiri Nairobi 00100 Kenya
3. School of Geography; University of Leeds; Leeds LS2 9JT UK
4. Kenya Agriculture and Livestock Research Organisation (KALRO); Kaptagat Rd, Loresho Nairobi 00200 Kenya