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4 EBONY Ebony trees (Diospyros species, Ebenaceae) are renowned worldwide. Their black, rock-hard wood is perhaps the smoothest, shiniest, and most beautiful of all. It is almost a precious material, sometimes sold by the gram like gold. But Diospyros, the generic name for these plants, actually means âfruit of the gods,â and outside the tropics ebony species are renowned for the persimmon. Originally from China, persimmon (Diospyros kaki) has for centuries ranked among the most prized fruits in certain areas, notably Japan and parts of Europe. Now it is gaining a more extensive following, with commercial production rising in the United States, Europe, Israel, and elsewhere. Thanks to genetic selection, airfreight, and advanced materials, an international trade in this fragile fruit is now beginning, with Israeli persimmons flying first-class all the way to Europe and the United States. Almost unappreciated at present is the fact that most species in this genus are tropical, and that the species of Africa, Southeast Asia, and the Americas also bear fruits. Typically, those fruits are yellow, red, or purplish in color, about the size of golf balls, sweet and tasty, exceptionally abundant, and widely enjoyed. Examples include the black sapote (Diospyros ebenaster) of Mexico and the velvet apple (Diospyros discolor) of the Far East. Although hardly anything is known about Africaâs ebonies as crops, their long-term prospects could be good. These counterparts of the persimmon seem adaptable species; occurring from dry to humid zones all across the continent, from Senegal to Sudan and from Sudan to South Africa. This suggests that various ones could in the future be grown more widely too, and not only as scattered village trees but also as densely planted stands. For agroforestry projects, African Diospyros species could be especially valuable. They are trees people know and love. As long as planting materials of superior types are supplied, millions are likely to plant them spontaneously and protect them from harm. Even now, volunteer plants are well cared for.1 Indeed, these African ebonies could become valuable not only for individual plantings but also for bordering streets and highways, for fencelines, for village plots, and for small-scale entrepreneurial endeavors (care should be taken when introducing ebonies to new areas, however, as 1 This is true of D. mespiliformis in Namibia, for instance. Information from P. du Plessis. 253
254 LOST CROPS OF AFRICA Jackal berry tree, Kruger National Park, South Africa. The best known and most developed ebony-fruit species, the jackal berry (Diospyros mespiliformis) is typical of the group. Its black, rock-hard heartwood is used for carvings, but locally it is more renowned for its fruits, a popular favorite. (Willem van der Merwe) some species may be invasive of open ground.). In certain areas ebony forests might be established as food reserves, which would likely be an excellent way to obtain local cooperation for planting and protecting both trees and land. In the long run, however, the very valuable wood could be the greater financial prize. Despite their domicile in the wild, African persimmons are particularly enjoyed. For marketing on a large scale, they are suitably sized, attractive to look at, and appealingly sweet and succulent. They are, however, very soft and delicate. And this fragility is at present the biggestâperhaps onlyâ thing limiting their advancement into big time food resources.2 These fruits are versatile. Most are eaten fresh. Many are eaten dried. Some are pulped and incorporated into sauces. A few are reduced to concentrate, sometimes sold in frozen form. Others are incorporated into 2 âThey are virtually impossible to transport fresh,â wrote one of our contributors, âbut they dry very well.â
EBONY 255 porridges, toffees (called maâdi in Hausa), fermented drinks, and even a distilled liquor, âebony brandy.â They also help save lives. People keep the dried fruits as a reserve for use following the end of the farming season, a period when food often runs out. But even then ebony is much more than a famine food. Africans often consider this local version of dried apricot much better than the real thing. As far as nutrition is concerned, little is known with certainty. The fruit pulp consists largely of water and carbohydrates, with small quantities of minerals for good measure. Details of the vitamin content are so far unreported, but the pulp can be expected to be a source of vitamin C, with perhaps 25-50 mg per 100 grams. Interestingly, like apples, commercial persimmons have more vitamin C in their skin than in their flesh. That skin can have more than four times the already substantial amount it encloses. In addition, the skinâs bright red color likely reflects the presence of lycopene, a nutritionally important carotenoid found in tomatoes. Fruit pulp is not the only useful resource these trees confer. Others are: Seeds Seeds are said to be edible, but this seems to depend on species, and does not apply, for instance, to Diospyros mesipiliformis.3 Foliage The leaves are used as animal feed. Bark In some species a bark infusion yields a dark blue dye for coloring cloth. Also, the injured bark exudes a gum, useful as glue. Wood The world famous fine-grained black or dark-brown heartwood is used in cabinetwork and carving. Because of its termite resistance, it has long been employed for posts in house construction. More valuable personal uses include tool handles, pestles and mortars, and small dugout canoes. Most valuable of all is ebonyâs use in sculpture and crafts, for which it sells by the gram. In the past, some was burned for firewood and charcoal, a phenomenon now almost unthinkable. PROSPECTS These plants are quite versatile and adaptable. The limitations on ebony- fruit enterprises lie mostly with the softness of the fruit. Just which zones within Africa are best for ebony-fruit enterprises is today a guess. Possibilities are: 3 According to contributor Harry van den Burg, the roasted seeds of Diospyros whyteana make a surprisingly good substitute for coffee.
256 LOST CROPS OF AFRICA African ebony fruits under development as an orchard crop in Israel. These persimmon counterparts could in future be widely grown both as scattered village trees and also as densely planted stands. Although hardly anything is known about Africaâs ebonies under cultivation, their long-term prospects as fruit-and-timber resources could be good. The sale of fruits would support the annual maintenance costs and perhaps provide income during the long years in which they are laying down their heartwood, which is so prized by artists it can be sold to the world in small select pieces. (Yosef Mizrahi) Humid Areas Excellent prospects. Because most African ebonies hale from the humid lowlands, hot and steamy sites they would seem to offer excellent prospects, perhaps even in sizeable plantations. Also possible is the concept of âsalvation farming,â in which threatened native forests would be endowed with economic value by organized harvests of sustainable forest products, including ebony fruits. The importance of this lies in the fact that forests producing food and income have a better chance of being spared the match, machete, or chainsaw. Dry Areas Modest prospects. Clearly, Africaâs most desiccated zone will never be prime ebony fruit country, but the Israeli experience indicates that good production might be achieved in certain dry areas, especially if a little irrigation can be found. Forestry and agroforestry projects throughout the savanna region should consider incorporating at least a few of these trees into their testing programs.
EBONY 257 Upland Areas Doubtful prospects. The potential for Africaâs ebony fruits for Africaâs highlands is untested. It will depend on species, latitude, and altitude, as well as site orientation and consequent exposure to cold. At the very high zones of Ethiopia, for instance, potential is likely to be zero. But at lesser elevations across the continental uplands, it could well be excellent. NEXT STEPS Now is the time to reconsider these species. Given horticultural selection, ebony fruits may prove just as appealing to tropical Africa as the persimmon is to the temperate world. Foresters, pomologists, and interested plantsmen and plantswomen throughout Africa could probably develop the native persimmons into important crops without massive expenditures or major governmental interventions. But to achieve any sweeping success will take teamwork among persons with differing skills. For one thing, plant-nursery workers and others skilled in propagating plants are urgently needed. Vegetative propagation has not yet been reported, but is probably not difficult to accomplish. In the wild, the trees regenerate by coppice and root suckers as well as by seed. Older seed has a built-in dormancy, but that is easily overcome with hot water treatment. Although seedlings grow slowly at first, they later elongate rapidly. Apparently, they can be transplanted into forest clearings, but, due to their slow early growth, need a lot of weeding. Foresters could also contribute. Ebony is not only ranked among the worldâs finest woods, it is also already often associated with Africa and Africans. So far, however, there have been few, if any, attempts to produce it in plantations. Largely, this is owing to the treesâ perceived slow growth and the expectation of a financially devastating delay between planting and harvesting. But all this may change if annual crops of valuable fruits can be harvested during the years the trees are maturing to timber size. With some testingâas well as with some cleverness or luck in selecting compatible sites and planting materialsâthese plants could well prove faster maturing than is now anticipated. Indeed, evidence suggests that this might be true even now. Diospyros lycioides, for instance, is an ebony bush bearing heavy crops of pleasant fruit that grows fast.4 The skills of food scientists are also needed. Harvesting and handling these fragile fruits is an especially uncertain topic. In general, the trees flower in the rainy season and ripen their fruits in the dry season. In humid lowland forests fruits ripen about 6-8 months after flower fertilization, but in hot, dry woodlands they ripen much faster. Although the ripe fruits are usually collected from the ground, they may be picked from the tree. 4 In Swaziland the rate under good conditions is half a meter a year or more. Information from Harry van den Burg.
258 LOST CROPS OF AFRICA Anthropologists and others interested in traditional cultures could do much to help. The different species, different traditions, and different experiences with these fruits in various parts of Africa are uncollated. Someone should pull together a corpus of continent-wide knowledge. Important insights into the propagation, horticulture, harvesting, handling, and processing of the different species will be gleaned from such work. Non-specialists can help as well. One necessary step is to gather germplasm in the different and varied regions where the ebony fruits grow, a task perhaps best done by those residing in the remote rural regions. Another interesting approach is to convene contests for the biggest, sweetest ebony fruits. People who are observant and adventurous are likely to respond eagerly. Thus, there are likely to be many budding winners, whose germplasm could be of benefit to all Africa. Although individuals throughout Africa need to contribute their time and talents to the selection, propagation, and other studies of the ebony fruits, the development of these crops could also be a good topic for voluntary and economic-development assistance from Japan. Its experts and expertise on the horticultural development of Japanese persimmon might well provide a key to quickly achieving the potential inherent in Africaâs own counterparts. However, horticultural improvements will not occur overnight and much scientific groundwork remains to be done. All in all, thereâs much to learn about means for maximizing these plants fruit production. Examples follow. Fruit Quality One prime task is improving fruit quality, especially the strength of the skin. This is vital for making African persimmons suitable for mass markets. Superior types already exist, but they are scattered throughout the continent and their whereabouts is unrecorded. They need to be located and vegetatively propagated. Disseminating planting materials (such as scion wood) of these will give the crop a chance in exploratory production and perhaps even commercial-scale ventures. Overall fruit-quality features to consider include hardness, shape, size, color, general appearance, skin thickness, skin strength, pulp-to-seed ratio, and tannin levels. Fruit size is a straightforward target for selection. Todayâs African ebony fruits are much smaller than a persimmon, but larger-fruited forms undoubtedly exist. These should be plucked from hiding. Fruit-size might also be increased by horticultural or genetic manipulation or by improved management of the trees. Tannins need to be considered, too. It may seem likely that the immature African persimmons, like those in the rest of the world, will pucker the mouth. But those of the main African species are commonly tasty even unripe. Nonetheless, any chance trees with especially low-tannin fruits should be seized upon.
EBONY 259 Genetic Manipulation Hybridization between African species might produce larger (maybe even seedless) fruits. Also, hybridization with the common persimmon might perhaps lead to the betterment of both. Management Yields at present are low, but this is undoubtedly through lack of horticultural help. Attention should be given to the plantsâ needs for water, fertilizer, and pest and disease control. Grafting onto rootstock of the same or different species also needs testing, particularly because it might produce dwarf plants that would be easier to manage as food producers. Handling Chilling requirements for maximum storage, shelf life under ambient conditions, and overall quality control all need determining. Nutrition The nutritional composition and tannin contents of the various species and major genotypes should be assessed. Processing Processing is important with these fruits, which are often too soft and squishy to transport, especially in hot weather. Opportunities exist for manufacturing dried and preserved products as well as beverages and prepared foods, including porridges and toffees flavored with ebony fruit. Marketing Much can be done to better market fruits to consumers in African cities; many will be as new to ebony fruits as Europeans or Asians. Which of the numerous ebony-fruit species to advance is as yet uncertain. Below some possibilities are highlighted. JACKAL BERRY TREE The best known and most developed ebony-fruit species in Africa, the jackal berry tree (Diospyros mespiliformis Hochst ex A. DC) is also typical.5 An evergreen or semi-evergreen, it reaches 15-20 m tall in drier zones and up to 45 m in humid forests. Mature specimens have dense, wide-spreading, rounded crowns with trunks that are sometimes buttressed or fluted. However, in some regions the plant occurs only as a large, multi-stemmed shrub. It is common in the gallery forests alongside rivers in southern Africa. According to at least one observer, these forests constituted one of the major habitats in which humans evolved. This fruit, therefore, is likely to be one of our oldest foods of all. Male and female flowers appear on different trees: males in clusters; females solitary. The fruits are more or less round, up to 3 cm in diameter, greenish and hairy when young, yellow or purplish and smooth when ripe. 5 Vernacular names are abundant, including mu-koro (Kikuyu) and gughan (Arabic), eenyandi (Oshiwambo), and ngombe.
260 LOST CROPS OF AFRICA The pulp of these small fruits is very sweet. This is one that is quite tasty even when not completely ripeâit seems remarkably tannin-free for a persimmon. The 4-6 dark brown seeds are oblong, flattish, minutely warty, and hairy. As for known environmental requirements, they can be summarized as: Rainfall The tree is generally found in areas receiving from 500-1,270 mm in four out of five years, but grows also in areas with around 300 mm (Chad and Namibia, for instance). Altitude It grows naturally up to 1,250 m (in Tanzania, for instance). Temperature In areas with mean annual minimum temperature of 16Â°C. Seems to grow best in areas with mean annual maximum temperature of 27Â°C. Soil The species appears to favor heavy soils, but is not unhappy in sands, loams, volcanic soils, or rocky sands with clay or alluvium. OTHERS Yet more ebonies bearing heavy crops of pleasant fruits include the following from southern Africa (often called âblue bushesâ in the region): Diospyros lycioides Desf. This small shrub of central and southern Africa bears reddish or yellow fruit the size of small plums. The pulp is translucent and faintly sweet.6 This is the species that grows fast. In Zimbabwe it produces fruit after 4 years, while still in the nursery.7 Moreover, its wood is high in quality. Twigs from this species are commonly used as a toothbrush and have been found to contain effective antibacterial compounds.8 Diospyros kirkii Hiern In spring this small tree of the tropical lowveld of southern Africa bears sweet mealy fruit (2.5-4 cm in diameter). The fruits are good enough eating and the trees are resilient and productive enough that one writer, after surveying hundreds of wild food plants, considered this species as âperhaps being worth domesticating.â 6 âThis is a nice fruit,â wrote our contributor Harry van den Burg. âIt has three subspecies [here] in Swaziland, and lots of genetic variability that is worth exploring.â 7 Information from Ray Perry. 8 Cai L., G.X. Wei, P. van der Bijl, and C.D. Wu. 2000. Namibian chewing stick, Diospyros lycioides, contains antibacterial compounds against oral pathogens. J. Agric Food Chem. 48(3):909-914.
EBONY 261 Diospyros batocana Hiern Not all African persimmons are smallâthis one is apple sized. Those yellowish-orange fruits have a very acid pulp that is said to be refreshing on a hot day. Diospyros chamaethamnus Dinter ex Mildbr. The inhabitants of Namibia and Botswana (especially San and Okavangos) regard this as one of their most important foods. They say âa man could live on these fruits alone for three months, provided that water was available.â The gelatinous flesh is commonly pulped in water and drunk as a sweet, milky beverage. Diospyros pallens Thunb. Southern Africa. According to one account, local fans can eat at one sitting as much as a kilo or two of these red fruits, which when fully ripe taste like raspberries.