Fig. 5. Change over time in Chivi for three scenarios (rainfall patterns in the different scenarios are the same) using a simple additive index. Scenario A, no interventions; Scenario B, crop yield and livestock pen feed raised by 20% per year, and 10% of all trees removed in year 2; Scenario C, crop yield and livestock pen feed raised by 50% per year, and 20% of all trees removed in year 2. The index is derived from average values for four variables, with the values being derived from a Stella simulation model.