Independent: Like most people living along the Sahel the drylands between Africas tropical savannahs and the Sahara Desert Mustafa Ba is all too familiar with the effects of desertification. Thanks to a combination of overgrazing and deforestation, he has watched the countryside around his Senegalese village, Mboula, turn into a dusty, unproductive wasteland. Trees provide us with many benefits, explains Mustafa, as we sit on a mat in the centre of his village. They are good for the soil and important...