The Great Green Wall: sustainable reforestation under the close scrutiny of the scientific community

A 15km-wide strip of vegetation that runs for 7,600 km through 11 countries in Sub-Saharan Africa… The objective of the Great Green Wall is beyond belief. By creating a tree-filled area across the Sahel, the challenge is to bring about the emergence of viable plantations under the watchful eye of researchers who are studying the project’s initial findings.

Environment and biodiversity

African Sahel

Thierry Vandevelde

60 000 € by the 09/06/2011 Board of Directors
50 000 €  by the 10/06/2013 Board of Directors
30,000 € by the 04/04/2016 Selection Committee

Project Leader

Observatoire Homme-Milieux de Tessekéré

The African Sahel is currently one of the world’s most vulnerable regions. While it enjoys great eco-geographical and social diversity within its territories, the entire region nevertheless suffers increasing ecological and social vulnerability, which stresses the need for urgent, concerted action.
Gilles Boëtsch
Research Director, Special Class, CNRS

This ambition so much exceeds anything imagined so far that Senegal President Abdoulaye Wade has called the Great Green Wall an “insane project”. In a move towards sustainable development, the project should lead to the revitalization of the African Sahel. This arid zone is one of the world’s most vulnerable regions and concentrates a rather large amount of climate difficulties. In an attempt to give another chance to this trans-border territory, the “Great Green Wall for the Sahara and the Sahel Initiative (GGWSSI)” was approved in 2007.


7,675 km in plantations

Technically-speaking, the Great Wall was designed as a strip of plant species adaptive to drought. The objective of this plantation programme is to create a tree-filled zone which is ecologically and economically viable for local residents. To those rural populations, some of which are nomads, the renewal of this environment is critical after it has been damaged by overgrazing, bushfires and routine lack of water. When the programme reaches a mature stage, the ziziphus, balanites and acacias will help the growth of the local economy, especially with the harvest of gum Arabic.
So the aim of the project is to reclaim a variety of plant and animal species sufficient to re-establish some ecological balance in Senegal’s Ferlo region. It is part of an integrated sustainable development approach, taking into account an improved standard of living for local populations through tangible initiatives to foster awareness, literacy and ongoing medical care.

Whether assisting residents in a vulnerable zone or conducting a scientific study, efforts by the OHM.I can help to analyse and understand changes in a semi-arid environment. This is a major advance that goes well beyond its sole benefit to Sahel populations.
Thierry Vandevelde

The GGW involves 11 countries bordering on the Sahara/Sahel zone, ranging from Senegal to Djibouti, stretching across 7,675 km with an average width of 15 km. The part of the project involving Senegal extends 535 km and covers about 80,000 hectares. The country is a pioneer with respect to this issue and has been closely monitoring the results: around the villages, “versatile gardens” are now starting to produce fruits and vegetables.


A scientific research segment dealing with ecological restoration and forest regeneration

The initiative is monitored by the Man/Habitat Watchdog International (OHM.I). Based in Téssékéré, Senegal, this multi-disciplinary laboratory was founded in 2009 at the initiative of the Institute for Ecology and the Environment at the CNRS and of Cheikh Anta Diop University (Ucad) in Dakar. It includes botanists, plant ecology specialists, doctors, anthropologists and geographers, who are all studying this recovering environment through four fields of research: water and soil resources, biodiversity, social systems and health. In this way, the impact of reforestation can be measured in a wide range of scales like microbiology, ecosystems or sociology.

Planète Veolia NO.33 - March 2012 (325.3 KB)

Supported by the Veolia Foundation, the OHM.I’s efforts aim at understanding, modelling and raising awareness about the dynamics and relationships between Man and the Sahel environments, as they were in past, as they are nowadays and as they will be in the future. Specifically, the idea is to analyse the ecological and social impact of the plantations, ranging from their effects on the climate and the biosphere to their influence on biodiversity and its dynamics, on a scale ranging from microbiological life to plants and animals, as well as their repercussions on the living conditions of local populations.

An award-winning project

The Veolia Foundation has been rewarded for supporting the Great Green Wall. The Foundation scooped the Research and Environmental Prospects award at the 2013 Corporate Environment and Sustainable Development Sponsorship Awards.

A network of scientists has gradually been set up around the OHM.I. Discussions are being held to ensure that the work is being communicated throughout the scientific community and to relevant authorities. Thanks to support from the Foundation, the research unit has been consolidated, with about a dozen theses in progress, four of which have so far been defended. In addition, scientific authorities can meet on a yearly basis at a summer university.
As an instrument for applied research, the OHM.I is a highly credible example of how to combine the full range of disciplines that relate to the environment.