The Great Green Wall: trees to halt the desert

Creating a massive green belt stretching across all of Africa to stop the desert.

The Great Green Wall to combat desertification in the Sahel

Growing 7,000 km of dense vegetation

In the Sahel, the desert has been steadily gaining ground over the last few decades as woodland areas decline. Its advance brings with it rural exodus and poverty. What if we reversed the trend? 
  

The challenge is daunting: to recreate a new forest and extend it, running like a great green corridor across the entire African continent. A long green belt 15 km wide connecting Dakar to Djibouti: over 7,000 km of vegetation to slow down the desert’s spread.

Planting thousands of trees

In 2004, 11 African countries came together and decided to take up this challenge by creating the Pan-African Agency for the Great Green Wall. We chose to accompany them starting in 2012, offering our support to Senegal. 
Today, the mission is underway: more than 130,000 desert date palms have already been planted, and more than 45,000 hectares of desert have been revitalised with vegetation. These are lands where desertification is receding and life is returning. 

Multiplying species

What can be planted to combat desertification? We need plants that can survive the extreme conditions of the Sahel, such as the desert date palm (Balanites aegyptiaca), acacia trees (Acacia senegal, Acacia seyal) and the Indian jujube (Ziziphus mauritiana).

The Great Green Wall will be all the more sustainable if it is home to multiple species. Plant biodiversity increases resistance to climatic variations, insects and disease. Other shrubs and herbaceous plants are therefore needed to join the trees in this vast canopy. 

The desert date tree

Balanites aegyptiaca (L.) Delile

(Famille : Zygophyllaceae)

This tree can live for 2 years without water. It is resistant to brushfires thanks to its thick bark, and can live for over 100 years in harsh conditions. This makes it an excellent candidate to withstand the desert's onslaught! It also makes itself useful to people in various ways, by providing fruit, fodder, raw materials for construction or craftsmanship...

What is desertification?

The desert does not expand on its own; it requires land to degrade and become infertile. Why? Primarily due to climate fluctuations, such as droughts, and human activity. Intensive deforestation, overgrazing and drilling all play a large role.
 

In Senegal, a strong ambition

Senegal, a pioneer in the Great Green Wall program, began planting in 2008 in Ferlo, a region in the northeast, in the heart of the Sahel. The Senegalese "Water and Forests" Department is in charge of this operation, including its monitoring and assessment, and is also responsible for raising locals' awareness. It is the executive arm of the Senegalese Great Green Wall agency.

The Great Green Wall and the fight against poverty

An interesting feature of this program is that it combines the protection of biodiversity with a humanist vision. There are tangible, everyday benefits for the local population, such as improved food availability and an additional source of income.

The mobilization of local populations

Local people's involvement is an essential aspect of this program, especially in Senegal, where the program has progressed the most.
In the Ferlo region, several nurseries have been set up, in cooperation with locals. They are the ones who watch over the saplings that will be added to the Great Green Wall, making sure they grow correctly.
The men prepare the sleeves in which the seeds are sown, water the seedlings, and watch over the protected parcels and the seedlings. In return, they are allowed to harvest the parcels' first products (fodder, gum arabic...).

Vegetable gardens for the women

In Senegal, this initiative stretches far beyond the replanting of this vast forest of desert dates. By promoting soil recovery, this new plant cover has permitted the creation of 6 fruit and vegetable gardens. In return for maintaining the forest nurseries, over 1500 women are free to cultivate them and use the fruits and vegetables they produce.
In addition to diversifying the locals' diets, these fruits and vegetables are sold at markets, providing a source of income.

Our involvement

• he planting of 80,000 desert date trees, 10,000 per year over six years.
• The funding of 3 doctoral theses on the desert date tree and its impact on humans, health and the environment.
• Support for the annual science and medicine summer school in Senegal (civic and scientific activities, multidisciplinary exchanges).

The CNRS and its observatory

We have worked with the CNRS on this project since 2012. The National Centre for Scientific Research has established a Human-Environment Observatory (OHMi) to study the impacts of these plantations on the ecological, medical and social levels.

A project selected by “UNESCO Green Citizens, become a pathfinder for change”!

The "Great Green Wall" initiative was selected by UNESCO as an emblematic example of sustainable development education, one of a handful of projects from all over the world to be showcased.

National Scientific Research Centre (CNRS)

This prestigious public research centre is probably the most famous one in France. Through its 1,053 laboratories, it covers every scientific field, from the social sciences and humanities to chemistry and nuclear physics.

A major producer of Nobel prizes and Fields medals, the CNRS has a gift for revealing talents and, more importantly, for furthering knowledge.

Pour aller plus loin 

Envie d’explorer l’univers des plantes médicinales ? Parcourez notre page “Plantes médicinales” : fiches illustrées, vidéos et projets, du Sahel à l’Amazonie.