Africa's Indigenous Fruit Trees: A Blessing in Decline.

Abstract

For probably as long as people have lived in Africa, they have eaten culturally and traditionally important indigenous fruits such as baobab, desert date, black plum, and tamarind. Farmers have been able to enjoy the fruit of these plentiful wild trees without developing any knowledge of how to propagate them successfully; they haven’t needed to. Glossary Agroforestry: A land management system that integrates trees within other crops or livestock systems to improve the complex beneficial interactions with other organisms (bacteria, fungi, insects, birds, mammals) and so improve the ecological health of the system. Breeding: Cross-pollinating plants to produce a new plant with desirable qualities from both parents. In trees this is a relatively slow and inefficient form of domestication. Crop diversification: Introducing additional crops to what’s grown on a farm. Crop intensification: Using various methods to enhance crop yield. Cropping system: The pattern of crops grown and farming practices employed on a given field or farm. For instance, a polyculture cropping system involves growing a diversity of crops simultaneously in the same space. In conventional agriculture, cropping systems are often monocultures (growing a single crop at a time). Cultivar: A plant variety that is produced by breeding. Cultivation: Growing crops in a farm field. Cutting: A section of shoot or root cut from a plant, which is encouraged to form a new plant by developing roots and shoots (see “Rooting”). In contrast to plants grown from seeds, cuttings remain “true” to the plant from which they are taken. Domestication: Intentionally growing plants that originated in the wild, a process enhanced by selecting the best specimens and propagating them vegetatively (e.g., by taking cuttings as opposed to planting seeds). Grafting: Taking sections of branch from a mature tree and fusing them onto a small seedling. The result is a new plant with the characteristics of the mature tree. “Multigrafted” trees produce a variety of fruit on the same tree, but this method is generally more of a novelty than a production system. Propagation: The act of producing new plants by any method. Rooting: Stimulating a cutting to develop and grow roots, typically by inserting the cutting into a humid environment with a damp, loosely packed medium such as peat moss or vermiculite. Smallholder: A farmer working 2–5 hectares of land with a combination of cash crops to sell and food crops to feed and support the family. However, the trees’ natural habitats are being lost, mainly to widespread deforestation resulting from population growth, the cutting of trees for firewood or charcoal, and in some cases industrial agriculture or other business interests. With this loss, questions arise over where the trees will grow in the future, if at all—and whether they will continue to provide the same wide range of benefits if they do survive. Fruits native to the African continent offer nutrients that often come up short in local diets, and they grow on trees that provide a range of ecosystem services. But deforestation is threatening Africa’s indigenous fruit trees. Now researchers ... Trees of all kinds provide immeasurable ecosystem services, including carbon sequestration, continual replenishment of soil, and removal of pollutants from air.1 Wooded areas foster biodiversity, which provides benefits of its own. For instance, deforestation is associated with increased risk of malaria transmission due to an increase in mosquito breeding sites on cleared land and reduced populations of mosquito predators.2 What’s unique about fruit trees is their ability to provide vital nutrients that may otherwise be scarce.3 Indigenous fruit trees, in particular, have still another added benefit: Naturally adapted to local soils and climates, wild trees often survive environmental stresses better than introduced species.4 A growing number of researchers, conservationists, and plant domesticators are fighting to reverse the population declines these native fruit trees are experiencing. Across Africa and in other parts of the world, scientists are studying their nutritional and ecological benefits and how those properties could be enhanced if the wild trees are domesticated. They’re also characterizing the genetic diversity of the trees and working with growers to ensure their successful cultivation, often as new crops, with the potential to transform local agriculture.5 Farmers are considered a crucial part of preserving the future for indigenous fruit trees, which, in turn, are viewed as a means for improving the livelihoods of poor smallholder farmers in particular. “The future of trees is on farms,” says Ramni Jamnadass, leader of the Quality Trees Global Research Project at the Nairobi-based International Centre for Research in Agroforestry (ICRAF). The center, also known as the World Agroforestry Centre, is the driving force of much of the research on African indigenous fruits.6 “If we don’t invest in them now,” Jamnadass says, “we will lose many of the species, as many of them are fast disappearing.”