GUIDAN BAKOYE, Niger: In this dust-choked region, long seen as an increasingly barren wasteland decaying into desert, millions of trees are flourishing, thanks in part to poor farmers whose simple methods cost little or nothing at all.
Better conservation and improved rainfall have led to at least 3 million newly tree-covered hectares, or 7.4 million acres, in Niger, researchers have found. And this has been achieved largely without relying on the large- scale planting of trees or other expensive methods often advocated by African politicians and aid groups for halting desertification, the process by which soil loses its fertility.
Recent studies of vegetation patterns, based on detailed satellite images and on-the-ground inventories of trees, have found that Niger, a place of persistent hunger and deprivation, has recently added millions of new trees and is now far greener than it was 30 years ago.
These gains, moreover, have come at a time when the population of Niger has exploded, confounding the conventional wisdom that population growth leads to the loss of trees and accelerates land degradation, scientists studying Niger say. The vegetation is densest, researchers have found, in some of the most densely populated regions of the country.
"The general picture of the Sahel is much less bleak than we tend to assume," said Chris Reij, a soil conservationist who has been working for more than 30 years in the Sahel, a semiarid belt that spans Africa just below the Sahara and is home to some of the poorest people on Earth.
Reij, who helped lead a study on Niger's vegetation patterns published last summer, said, "Niger was for us an enormous surprise."
About 20 years ago, farmers like Ibrahim Danjimo realized something terrible was happening to their fields.
"We look around, all the trees were far from the village," said Danjimo, a farmer in his 40s who has been working the rocky, sandy soil of this tiny village since he was a child. "Suddenly, the trees were all gone."
Fierce winds were carrying off the topsoil of their once productive land. Sand dunes threatened to swallow huts. Wells ran dry. Across the Sahel, a cataclysm was unfolding.
Severe drought in the 1970s and '80s, coupled with a population explosion and destructive farming and livestock practices, was denuding vast swaths of land. The desert seemed determined to swallow everything.
So Danjimo and other farmers in Guidan Bakoye took a small but radical step. No longer would they clear the saplings from their fields before planting, as they had for generations. Instead, they would protect and nurture them, carefully plowing around them when sowing millet, sorghum, peanuts and beans.
Today, the success in growing new trees suggests that the harm to much of the Sahel may not have been permanent, but a temporary loss of fertility. The evidence, scientists say, demonstrates how relatively small changes in human behavior can transform the regional ecology, restoring its biodiversity and productivity.
In Niger's case, farmers began protecting trees just as rainfall levels began to rise again after the droughts.
Another change was the way trees were regarded by law. From colonial times, all trees in Niger had been regarded as the property of the state, which gave farmers little incentive to protect them. Trees were chopped for firewood or construction without regard to the environmental costs. Government foresters were supposed to make sure the trees were properly managed, but there were not enough of them to police a country more than twice the size of France.
But over time, farmers began to regard the trees in their fields as their property, and in recent years the government has recognized the benefits of this by allowing individuals to own trees. Farmers make money off the trees by selling branches, pods, fruit and bark. Because these sales are more lucrative over time than simply chopping down the trees for firewood, the farmers preserve them.
The greening began in the mid-1980s, Reij said, "and every time we went back to Niger, the scale increased."
"The density is so spectacular," he said.
Mahamane Larwanou, a forestry expert at the University of Niamey in Niger's capital, said the revival of trees had transformed rural life in Niger.
"The benefits are so many it is really astonishing," Larwanou said. "The farmers can sell the branches for money. They can feed the pods as fodder to their animals. They can sell or eat the leaves. They can sell and eat the fruits. Trees are so valuable to farmers, so they protect them."