Desert date trees to fight against desertification

Balanites aegyptiaca adulte

Balanites aegyptiaca adulte

The African Sahel is currently one of the most vulnerable regions in the world. Although the eco-geographic and social diversity of its territories is great, the whole region is nevertheless affected by an increasing environmental and social vulnerability, highlighting the urgent need for concrete action. Yet, the desertification phenomena, exacerbated by global warming and human activities, is not irreversible.
 

ADAPTING TO CLIMATE CHANGE: THE "GREAT GREEN WALL" PROJECT

From this point of view, the endorsement of the Great Green Wall for the Sahara and Sahel (GGW) initiative in 2007 is a major step forwards. Technically, the green wall is 15 km-wide on average and is designed as a line of economically valuable plant species able to adapt to drought conditions. The project involves all 11 countries bordering on the Sahara-Sahel region, extending from Senegal to Djibouti and covering a distance of 7,675 km. 

The Senegalese part of the project extends over 535 km and covers an area of approximatively 80,000 hectares. The route of the GGW includes 30 rural communities and corresponds to an area dominated by pastoral activities. In Senegal, reforestation linked to the GGW is in full swing, with 5,000 hectares planted each year since 2008.


THE DESERT DATE: A MODEL TREE FOR THE ECOLOGICAL RESTAURATION OF DRY AREAS

Among the selected tree species for this reforestation project, Balanites aegyptiaca, or the desert date tree, holds a special place: it is indeed extremely resistant to drought as well as having a set of natural regeneration strategies (through seeds, suckers* and rejuvenation*). Unlike many other species that cannot bear the pressure from by livestock farming, B. aegyptiaca thrives with the constant passage of animals in the Ferlo forestry-pasture region in Senegal, as seed germination is facilitated by the circulation of the fruit and seeds through animals' digestive systems. 

Harvesting Balanites aegyptiaca fruit

Moreover, and beyond its ecologic interest, studies led since 2011 by the researchers of the international Observatoire Hommes-Milieux of Téssékéré (CNRS-UCAD) have demonstrated that the desert date is the tree that local populations of the Ferlo area use the most, for various purposes: food, fuelwood, fodder for their livestock and medicinal uses. The consumption of wild Balanites aegyptiaca fruit is a means to diversify food intakes during lean seasons*, and more specifically during the dry season. B. aegyptiaca produces yellow fruit similar to dates and a healthy mature tree produces up to 10,000 fruits per year, of which the pulp contains 64 to 72% carbohydrates, approximatively 10% proteins, saponins, vitamin C and other minerals. The seed is rich in oil (up to 4.7% of the dry weight) and unsaturated fats, with a composition in fatty acids close to that of soy beans, which explains why this oil is widely used by local populations.
All of its characteristics – its extensive geographic distribution in Africa, its adaptability to arid environments and its multiple uses – make B. aegyptiaca a model tree species for the restauration of ecosystems in dry areas.

 *sucker: shoot from the root of a plant that may become autonomous and can be replanted as a new individual.
*rejuvenation: action of cutting a tree close to the ground in order to obtain new shoots.
*lean season: period when the previous harvest has been used up and the new crops have not yet been harvested.