Figure 3: Scatterplot of tree cover in natural areas.

(a) Tree cover versus (and stratified on) mean annual rainfall (MAR) with Markham seasonality index (MSI) as colour scale and (b) Tree cover versus (and stratified on) Markham’s seasonality index with MAR as colour scale. In the rainfall range of bimodality (1,400–1,900 mm), the differences of seasonality between forest (>40% tree cover) and savanna (<40% tree cover) were found significant with a t-test and also with the nonparametetric Mann–Whitney test (P≈0). This is also the case for the rainfall differences in the bimodality range of seasonality (0.45–0.62) (P≈0).