In the far north of Cameroon, Nigerian refugees have been fighting desertification for four years. The desert advances by 12% each year in the region, which receives on average three times less rainfall than the rest of the country. But UNHCR hopes its program at Minawao camp can help turn the tide. More than 360,000 plants have already been cultivated in the nursery and planted on more than 100 hectares. Report from our correspondents.