This paper argued that the traditional values and practices of the semi-nomadic Pokot and Turkana peoples of Kenya provided an excellent basis for institutional efforts to sustain the pastoralists' semi-arid environments. Both groups managed pasture lands adaptively and co-operatively, under the leadership of elders. Trees along water courses were under individual tenure, highly valued and rarely cut, though people did not plant trees and failed to see the connection between seedlings and productive mature trees. The author argued that the many inappropriate and damaging interventions in the area, for instance intensification of land use, could be usefully replaced by developments that start with what people know, build on indigenous strategies and strengthen local rights of tenure.