Three years ago northern and central African nations that form the Community of Sahel-Saharan States agreed to a continent-wide belt of trees to combat the remorseless spread of the Sahara Desert. This past June they laid the groundwork for the Great Green Wall of Africa by formally adopting a two-year, $3-million initial phase for the project.

Green barriers against the Sahara have been around since the 1960s, but most have been small in scale. In contrast, the Great Green Wall will be 15 kilometers wide and will involve stretches of trees from Mauritania in the west to Djibouti in the east—a distance of some 7,000 kilometers. The aim is to protect the Sahel Belt—the dry savanna south of the Sahara—and prevent its precious arable land from desertification. The trees would also provide a source of firewood, crops and jobs. Projects to water these trees—say, by harvesting rain—could also help communities irrigate their fields all year long or even help them raise fish.

Pilot planting efforts, using local trees such as acacia (below), were scheduled to have begun in September. Funding for the entire project—perhaps its main stumbling block—still remains tentative.