Fig. 2: Distribution of tree cover by rainfall and percent cover.
From: More than one quarter of Africa’s tree cover is found outside areas previously classified as forest
a Total tree cover area by rainfall. Tree cover is classified into forest at different heights21, and into two groups of trees outside forest (TOF) with canopy cover <10% and 10–25%, respectively. A current state-of-the-art global map is added for comparison12. This figure highlights the regions below 1200 mm rainfall and the full map is shown in Supplementary Fig. 2a. b Tree cover vs. rainfall at 100 m resolution using a random sample of 10 million grids, with hue as the forest height21, and isolines overlaid for MODIS tree cover49 from 100 000 samples at 250 m, with isoline units as relative probability per rainfall and cover grid cell. c Contribution of trees outside forests (TOF) to total tree cover at country scale. We group trees in 30 × 30 m grids and define a cell as non-forest if the canopy cover is below 25%, and as forest, if it exceeded 25%. Tree cover is subsequently accumulated for each country. The ocean basemaps are from www.naturalearth.com.
