A new kind of revolution is simmering in the African heart of the third world. Its troops are not soldiers - but trees. Its partisans at their Nairobi headquarters see it as a natural and necessary successor to the ''green revolution'' that has spread high-yield agriculture among the developing nations.
In recent years the need for energy has mushroomed along with the need for food, while trees have disappeared for firewood and left desert areas expanding. The demand now is for growing trees in close harmony with crops, animals, and people to meet food, fuel, and environmental needs all at once. Trees, for example, whose leaves provide mulch for grass, maize, or other companion plantings; whose pods provide feed for cattle; whose limbs provide firewood or charcoal; whose roots deter erosion. Trees that may offer greens for salad, fibers for rope-making, fruits for the table -- and deterrents to water evaporation and the spread of deserts.
The mix of trees, crops, and animals must be carefully calculated for every situation. But the result can be fully efficient use -- and replenishment -- of land. This is vital in a period when population is rising to levels that sharply reduce the world's margin for waste of anything. A few years ago the World Bank estimated that tropical forests would be gone in six or eight decades at the current rate of depletion.
Growing crops and trees on the same land is not new in itself. Travelers to Kenya can see living examples right outside Nairobi: pastures with croton trees providing shade for animals and nectar for honey bees; fences made of the same trees, whose limbs can be pruned for firewood.
What is new and potentially revolutionary is the effort to make a widely applicable science of the blending of agriculture and forestry. It is called agroforestry. Its catalytic agent is a young organization, the International Council for Research in Agroforestry, which looks out from Nairobi to signs of interest and progress in many lands. The council was established a few years ago by Canadian, Swiss, and Dutch development agencies. It is picking up more and more support elsewhere. It should gain increased attention as the demand for renewable resources and optimum land use spirals.
One particular reason for urgency is the destruction of tropical forest resources caused by an age-old practice providing food for millions of people not only in Africa but Latin America, Southeast Asia, and elsewhere. This practice affects almost a third of the world's usable soil. It involves cutting trees for farming and then repeating the process elsewhere as fertility diminishes and land is abandoned to lie fallow until fertility naturally returns. With the pressure of population and loss of land to other purposes, the fallow periods on the remaining land have often been shortened to the point of exhausting it for agricultural purposes.
Enter agroforestry. The effort to take the best of the old wisdom and apply it more effectively in relation to all the factors of today. So the council offers developing nations help with diagnosis, design, trial, and evaluation of agroforestry projects. It knows, for example, that legumes planted with rubber trees in Malaysia permit the trees to be tapped in four years rather than the six years without legumes. It knows that the black wattle tree can restore degraded land and help it yield crops without nitrogen fertilizer - and also provide that extract for leather tanning which is one of Kenya's principal exports. One of the things the council is currently looking into is a company's request to find a wood to replace the eucalyptus it buys from small growers. The latter cannot use their land for other things if they grow eucalyptus, but they could diversify with some other trees that might equally serve the company's needs.
The magnitude of the challenge for the third world may be indicated by the fact that, even in a developed country like Canada, a recent report calls for a 50 percent increase in forest production by the year 2000. Eight thousand foresters will be needed during the next decade.
So the agroforestry council has its work cut out for it, spreading the word to the nations that can use it, responding to the inquiries that are accelerating, seeking support for the cooperation between forestry and agriculture specialists that has not been conspicuous in the past. May their revolution take root and grow like the trees that hold such promise for the needy places on our planet.