Trees Put a Crimp in a Creeping Desert
An international project cultivates forested areas in Niger to provide a windbreak from the spreading Sahara. ENVIRONMENT
ALONG the road north in Niger that leads into the Sahara, clusters of farmers pick at the earth with sticks and flat blades. Their crops of maize grow unevenly in hard, flat fields that are constantly blown by the wind. On the edge of the great desert, they seem to be fighting a losing battle.
The Sahel, an Arabic word that means ``shore,'' is a fragile belt of grasses and forests that stretches across northern Africa for 3,000 miles, from Senegal to Chad, and separates the Sahara from southern equatorial rain forests.
The soils of the Sahel are poor. Misuse and overuse by farmers and grazing animals have already caused considerable damage, resulting in desertification of once-productive land. According to many sources in the region, 30 percent of forested areas here have been lost to the sand in the last 20 years.
``It is not a question of the desert marching south, but of man making more desert,'' says Joe Kessler, director of the CARE International project that pumped $3 million into Niger last year for agroforestry projects.
``The real problem is the high population growth [3.1 percent each year] and overuse of the land. In Niger, people are moving to already marginal land.''
Niger overlaps both the desert and the Sahel and has been a testing ground for controlling ``desert creep.''
At least 60 international organizations run desertification projects in Niger. Millions of dollars are being spent - an estimated 40 percent of Niger's gross national product each year - but the results are a mixture of success and waste.
During the past three years, ``the gullies are getting bigger, the millet is getting smaller, the forests are disappearing, and per-capita grain yields have dropped exponentially,'' says Rick Van Den Beldt, principal agroforester at the International Crops and Research Institute for the Semi-Arid Tropics (ICRISAT) in Niamey, the capital of Niger.
``If they don't start doing something, there will not be much hope,'' Dr. Van Den Beldt says. To keep southern Niger, and the rest of the Sahel, from turning into a sandbox requires finding solutions for the myriad causes of desertification.
To improve crop yields and stop wind and water erosion, CARE began a windbreak project in Niger's Maggia Valley 16 years ago. Today, the valley is an impressive series of trees planted in double rows 100 meters (328 feet) apart, 600 meters to 1 kilometer (2/5 to 5/8 of a mile) long, perpendicular to the wind. So far, more than 700 kilometers (435 miles) of windbreaks have been planted in the valley and the project is recognized as one of the most successful in the Sahel.
The windbreaks are harvested in four-year cycles. The annual tree harvest has turned out to be one of the most clear-cut benefits of the project. This year, farmers culled 1,425 trees.
By protecting the young plant shoots from desiccating winds, the windbreaks have resulted in 18 percent greater crop yields. But Mr. Kessler says that statistics mean little here.
``From the farmers' perspective, they have a bigger difference in yield each year according to the rainfall, so it is difficult for them to see the benefits. It only hits home when they get money for harvesting the trees,'' he says.
Burning wood accounts for 80 to 90 percent of all the energy used in the Sahel. Thinning forests have made the precious commodity more expensive.
The law forbids cutting live, full-grown trees in Niger without a permit. But farmers often cut young trees that sprout on their land before they can provide protection from the wind. Once grown, trees can be an agricultural detriment, casting too much shade on small plots or robbing the soil of needed moisture.
The success of the Maggia Valley project has spawned similar windbreaks in other valleys, though none have been as effective. According to Kessler, CARE and other organizations have learned that no single solution can be applied everywhere in the Sahel.
At the CARE Tillab'eri site, 120 kilometers (73 miles) north of Niamey, windbreaks were started five years ago but have grown slowly because little rain has fallen and the water table is deep.
``It may be that trees are not right at Tillab'eri. Maybe we should be planting grasses, maybe we are doing a disservice and it is best to leave it fallow,'' Kessler says. ``There is a whole toolbox of things we can do - the key is to find the right one.''
Not every valley in Niger that is subject to Saharan winds can count on an international organization to save it. But it is difficult to convince farmers that trees planted today will benefit them a decade from now.
``People are much more worried about their day-to-day survival,'' says Leigh Heart, CARE's field director in the Maggia Valley.
Left to themselves, farmers would not be able to create large windbreaks or force everyone to bend to a ``greater good'' project, unless benefits were quick to follow.
``They will not do it for the good of the world, it is a bit much,'' Kessler says. ``Farmers are in no position to take a risk - it must be undertaken by development agencies.''
Other, more simple techniques, could increase crop yield and preserve the land.
Fencing around fields would stabilize the soils and allow more vegetation to grow. ICRISAT's Sahelian Center, 40 kilometers (25 miles) south of Niamey, has been circled by fences for six years and much of it was left to grow on its own. On a satellite photograph of the area, the center appears black, a green oasis in the middle of sandy, overgrazed land.
Also, in Niger, animals are used to show wealth, but rarely to plow fields. According to agricultural authorities, plowing with animals would save farmers four-fifths the amount of labor and the ridges formed would protect young shoots from wind. Crops can be twice as fruitful when planted on ridges.
``The most complex tools they use are the cutlass, axe, and fire - not the plow,'' says Phil Serafini, the research farm manager at ICRISAT in Niamey, who has worked in the Sahel for 12 years.
Part of the reason for the desertification of the Sahel has been occasional drought and changes in the climate, but Dr. Serafini does not see the Sahel in terms of an emergency.
``Every place in Africa has been drier before,'' he says. ``This is not outside the norms.''
The root of the Sahel's problem is poor soils, not lack of water. ``Most years we have enough water here - we are limited by the fertility of the land,'' he says.
The area cultivated in Niger has doubled in the last 25 years, and the population has nearly doubled since 1972. All the windbreaks and dune stabilization projects will not improve the phosphorus-poor soil.
By providing natural fertilizer, ``animals are the only source of long-term rejuvenation of the land,'' he says. But grazing animals, when not properly managed, destroy the fragile stabilizing grasses and trees in the Sahel.
Regardless of what farmers or international organizations do, the Sahel may be saved anyway, Serafini says. As the rest of the world considers the adverse effect of global warming, the Sahel could benefit.
``A one or two degree rise in surface temperature will cause more evaporation from the oceans, and the tropics will grow larger,'' he says. ``It may well be wetter here. Even with normal rains, though, this system can be productive.''