Plants: Varieties and Uses
The enormous array of plants native to Africa have always been a valuable resource for the continent's inhabitants. Africans use plants for food, medicine, fuel, paper, construction materials, and many other purposes. Some plants have been domesticated for agriculture; others are gathered in the wild. Africans have also adopted plants from other parts of the world, and a number of African plants are now grown on other continents.
Varieties of Vegetation
The vegetation that grows in any given area is determined by natural factors such as climate, elevation, and soil type, as well as by human activities such as clearing land, gathering firewood, and grazing livestock. There are three broad categories of African plant life: forest, desert and semidesert, and a group that includes open woodlands and grasslands such as the savanna.
Africa's forests cover about 20 percent of its land area. They are concentrated in the lowlands of coastal West Africa, the Congo basin of central Africa, and the mountains of East Africa. The tropical rain forests contain an astonishing variety of plant species, including many large trees up to 150 feet high. The rain forest on the island nation of MADAGASCAR is somewhat drier, with smaller trees, while the continent's Indian Ocean coast has a belt of similar lowland forest, mixed with evergreen trees. Africa also has dense mangrove forests along its tropical coastlines.
About 40 percent of Africa's land area is desert or semidesert. This includes the enormous SAHARA of North Africa and the Namib and KALAHARI Deserts in southern Africa. Vegetation in these zones consists mostly of tough, hardy bushes and grasses that require little water. These and other desert plants generally grow more readily in rocky areas than in areas of shifting sands. The Sahara has fewer plant species than most parts of the world. Some Saharan plants exist mostly beneath the surface, with wide-spreading root systems and only small parts exposed above ground.
Africa's semidesert zones gradually merge into grassy savanna or bushland, an area with mixed shrubs and thorny bushes. Some 40 percent of Africa is covered by grasslands, bushlands, and dry open woodlands, which have a thin covering of drought-resistant trees. The coastal areas of North Africa and South Africa—which have a Mediterranean climate with dry summers and mild rainy winters—contain woodland vegetation. Although these areas do not have dense forests, they contain some palm trees and hardy, low-growing species of oak, cedar, and juniper trees. A special type of grassland occurs along the NILE, NIGER, and ZAMBEZI RIVERS. Called sudd, which means “barrier,” along the Nile, it contains a thick growth of reeds and water plants that can interfere with river traffic.
People who live in Africa's tropical forests and woodlands gather and eat various wild fruits, though these are not major items in their diets except in times of food shortage. Instead, Africans cultivate a wide range of domesticated food plants. Food plants native to Africa fall into four main groups, each associated with a particular climate or environment.
The most widespread of these is the savanna food group, which consists of plants adapted to grassland and woodland environments. The key savanna crops are cereal grains, including sorghum, pearl millet, and rice. Sorghum, the most important of these, covers more ground than any other African food plant. Also in the savanna food group are watermelons, earth peas, black benne seeds (sesame seeds), and African tomatoes.
The forest margin group of plants includes the oil palm, the yam, a grain called Guinea millet, the kola nut, beans, potatoes, and peas. The third main group, the Ethiopian group, consists of plants native to Ethiopia in the eastern highlands of Africa. Among the plants in this group are coffee; teff, a cereal grain; noog, an edible oil plant; and a banana-like plant called enset. The last food plant group, the Mediterranean, includes date palms, grain barley, lentils, and olive and fig trees.
Other Plant Uses
Africa's plants have many other uses in addition to providing food. Thousands of years ago the ancient Egyptians perfected the art of making paper from the stems of papyrus, a plant that forms part of the sudd vegetation. Esparto grass, which grows on North African grasslands, is used in papermaking today and is exported by TUNISIA and ALGERIA.
Wood is Africa's primary source of energy, either as firewood or as charcoal, a fuel made of partially charred wood. City dwellers generally buy fuelwood or charcoal at markets, but rural people gather their own. Women are the main collectors and users of fuelwood for household purposes, favoring small pieces of dry, fallen wood that are easy to gather and carry. Men generally collect larger quantities and bigger pieces of wood needed for projects such as smoking fish and firing bricks. Fuelwood also provides energy for industries, such as tobacco curing in MALAWI. The demand for fuelwood is a leading cause of deforestation in parts of Africa.
Africans have traditionally built houses and other structures from plant materials. Construction usually requires many wooden poles of different sizes, bark-fiber ropes for tying them together, and grass for covering the roofs and sides of structures. Woodlands and forests are an important source of timber for construction. However, in places where forest resources have been overused, the large posts of durable wood needed as major support pieces in buildings have become scarce or even unavailable.
Wood is also the principal material for homemade or locally produced household items such as plates and bowls; for tools such as ax handles, bows, and arrows; and for CRAFTS such as wood carving. Certain trees are favored for particular uses—light, flexible woods for making bows and strong, split-resistant woods for ax and hoe handles. Other tree products include dyes, gums, oils, and chemicals useful in tanning leather. New leaves on trees and bushes are a welcome source of food for both domestic livestock and wild grazing animals during the dry season, and farmers and gardeners gather fallen leaves to use as fertilizer.
In addition to their practical uses, plants play a role in many African spiritual and cultural traditions. Groves of trees used as burial sites, for example, are often the settings for traditional religious ceremonies. The roots, leaves, and bark of many species of plants are key elements in traditional medicines, and many of the plants used are thought to have magical or religious properties. People in rural areas without formal health care facilities are especially dependent on plant medicines. Many Africans know how to select and prepare plant remedies for common ailments such as coughs, headaches, sores, and diarrhea.
For more serious complaints they may consult traditional healers or herbalists—specialists in the use of plant medicines. Although the disappearance of woodlands is making medicinal plants harder to find, an informal trade in these plants exists among collectors and herbalists in different African countries. (See also Deserts and Drought, Ecosystems, Food and Drink, Forests and Forestry, Healing and Medicine, Hunting and Gathering.)