Image caption Some experts say desertification is more about poor land management

Desertification in Africa's Sahel region may be driving a range of problems including terrorism. Gavin Haines investigates whether a project to reforest the region could help.

Since French forces were deployed to Mali earlier this year, the Sahel has emerged as a new battleground in the so-called war on terror.

This semi-arid region just south of the Sahara Desert has been described by the French military as "planet Mars" and is characterised by extreme heat, drought and food shortages.

Poverty is never far away and this, according to Kouloutan Coulibaly, Mali's Director of Forestry, makes it a breeding ground for extremism.

"When you have no money and no job and the terrorists come and pay, people say yes," he explains. "It's an opportunity for them."

Despite the lure, most eschew terrorism and continue to eke out their honest, knife-edge existences in this most inhospitable part of the world. Others abandon the Sahel altogether and head for new horizons.

A new leaf?

Many of the social and economic problems in the Sahel can be linked to a process called desertification.

We need to create resilient economies as well as environments Michele Bozzano, Bioversity International

"Despite what some people think, desertification is not the advancing of the desert - we are not talking about sand encroachment here," says Michele Bozzano, a research support officer for Bioversity International. "Desertification is about poor land management which turns the land into desert."

A report published this month by the United Nations Convention to Combat Desertification (UNCCD), claims that 850 million people worldwide are affected by desertification.

Overgrazing and deforestation are the primary causes of desertification and have turned vast swathes of the Sahel into dust. However, an ambitious reforestation programme known as the Great Green Wall aims to reverse this process.

Image caption Proponents say the project can combat instability in the region by opening up economic options for people

The project has been a pipedream in Africa since the eighties, when the idea of fighting desertification by planting a "wall of trees" across the continent first gained traction.

At 7,775km (4,831 miles) long and 15km (nine miles) the Great Green Wall was intended to snake through 11 countries, from Senegal in the west to Djibouti in the east.

However, the project has since evolved to become more ambitions in its scope and will now involve more than 20 African nations.

"It's more of a green mosaic than a wall," says Nora Berrahmouni, a Forestry Officer for the UN Food and Agriculture Organisation (UNFAO). "And it's more than simply planting trees - it could be a shrub or herbaceous plant. It's about mimicking nature and in nature you don't just see trees."

Essential to the Great Green Wall's success will be its ability to help sustain the lives of those living along it - the vegetation needs to be worth more standing than felled.

"We need to create resilient economies as well as environments," says Mr Bozzano.

Buy gum

It took years to secure funding for the Great Green Wall but with financial backing from the African Union, European Union, World Bank, UNFAO and other international investors, planting began in 2011.

When you plant a tree, who does it belong too, who is going to look after it, who is going to harvest the crop? Ced Hesse, IIED

Since then nearly 12 million trees have been planted in Senegal alone. Most of the trees are acacias, which are indigenous to Africa and have been chosen for their ability to survive in droughts and provide local communities with a source of income.

That income will come largely from a substance called gum arabic, which is extracted from the bark and is used as an additive in anything from pharmaceuticals to fizzy drinks.

Demand for gum arabic is currently outstripping supply, but to avoid creating an economy dependent on this wonder substance, Green Wall coordinators are trying to raise awareness about the other benefits of trees.

"Trees fertilise the soil and provide shade, which means the ground loses less water," says Mr Bozzano. "The difference between having a stable environment and not is the difference between being able to grow crops and crops failing - agroforestry is extremely important."

Counter terrorism

Assuming the Green Wall succeeds in reversing the effects of desertification - detractors argue that is a big assumption - could it really lift communities out of poverty and counter terrorism in the Sahel?

Mali's director of forestry certainly thinks so.

"The Green Wall is an opportunity to provide jobs and combat poverty," says Mr Coulibaly, who is currently unable to work in three rebel held territories of Mali.

"It will develop these regions and I think it will be a solution [to terrorism]."

But Michele Bozzano strikes a more cautious tone.

"Terrorists recruit people with money, they make them feel important and when you have nothing you are easily brainwashed," he says. "The Green Wall is about giving people alternatives."

However, not everyone is convinced this ambitious land restoration project can succeed.

Critics question whether it can survive in an area set to become even drier as the world warms up.

Image caption Critics say the way the wall project is managed does not connect well with the reality on the ground

"The Great Green Wall is about bringing back ecosystems that are able to adapt to a changing climate," explains Mr Berrahmouni, adding that only indigenous species capable of adjusting to droughts, are being planted.

Detractors also claim there are ownership issues with the Green Wall.

"When you plant a tree, who does it belong too, who is going to look after it, who is going to harvest the crop?" asks Ced Hesse, a Drylands Researcher for the International Institute for Environment and Development (IIED).

"The Green Wall is run from the top down and depends on external management and external funds, which doesn't necessarily marry well with what's happening on the ground."

The UNFAO disputes this and claims consultations with local communities are integral to the project.

One such community is Mboula, a dusty Senegalese village whose people are big advocates of the Green Wall.

"We knew we had to protect the land, but the Great Green Wall programme provided us with technical assistance," says Mustafa Ba, vice president of the regional council, as we sit on a mat with what seems like the entire village surrounding us.

"Instead of feeling alone facing this huge challenge of desertification, we feel connected to the rest of Africa and the outside world."

For the Great Green Wall to succeed against terrorism, statements like this must echo across the Sahel.