Chapter 3: Forestry and food production
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Wild foods from the forests
3.2 Food producing trees on the farm
3.3 Trees and shrubs as a source of livestock fodder
3.4 Trees and crop production
3.5 Food production from mangroves
The second chapter explored some of the ways that forests help maintain a stable environment: in the largest sense maintaining the global climate, as well as at the micro-level (e.g. the shade of a tree). The forest environment can, therefore, have an impact on food production: influencing soil, water, temperature and light regimes. Forests and farm trees also contribute directly to food security providing fruit, nuts and other edible foods. These contribute to people's diets in almost all rural areas; for some communities these foods play a major nutritional role. Forests also provide a habitat for a large number of animals, fish and insects which often provide essential additions to rural diets.
Less obvious are the many indirect contributions that trees and forests make to food production. In many livestock production systems, trees are an essential source of fodder, especially during the dry season, and thus contribute to meat and milk production. Mangrove forests provide essential habitats, especially breeding grounds for many fish species, thus helping to maintain fisheries in coastal areas. And as was discussed in the last chapter trees grown on farms can help improve soil conditions.
3.1 Wild foods from the forests
Food from wild plants
3.1.2 Food from wild animals
Forests and woodlands, and the wild plants and animals they contained, were once the main source of food for many early hunter-gatherer societies. Over the millennia, with the development of cultivated varieties of wheat, rice and the other staple crops, and the domestication of livestock, man's dependence on forests has declined. Nevertheless, there are a great many rural people who remain dependent on forests for critical portions of their food supplies.
Isolated forest communities exist where wild plants and animals are still the major source of food. In India, for example, some tribal groups depend almost entirely on hunting and gathering in forests and have little contact with the outside world. Similar communities exist in Papua New Guinea and in parts of Africa and Latin America. But while they are the most obvious examples, these are not the only people who rely on forest foods; for many millions of families living outside the forests, forest foods remain an essential supplement to their diet. The issues of who within a community depends most on forest foods, and to what extent are discussed further in Chapter 4.
The array of different foods consumed is vast; it ranges from beetle larvae to nuts and honey. For example, in the arid and semi-arid Sahelian belt of Africa, as many as 800 different edible plant species have been identified (Becker, 1986). One group of agro-pastoralists, the Tswana, use 126 separate plant species and 100 animal species as food sources (Grivetti, 1976).
Beetle larvae and honey nest
3.1.1 Food from wild plants
Several attempts have been made in recent years to catalogue forest food species (FAO 1982; FAO 1983a; 1983b; 1984; 1986a; 1986b). Although a large number of species have been identified with food uses, often this is as far as the information goes. Very little is known about the quantities produced, the seasonality of production, or its variability from year to year. Thus, it is often difficult to assess their relative importance as food sources.
Another factor which complicates the discussion of the relative merits of different forest foods is the pronounced differences in the quality of wild foods depending on varieties, ecotypes and provenances. The baobab tree, Adansonia digitata, is a good example; while some trees have soft and tasty leaves that are highly sought after by local people, with others the leaves are fibrous and bitter.
Broadly, forest plant foods can be categorized as leaves, seeds and nuts, fruits, tubers and roots, fungi, gum and sap. Collectively they add diversity and flavouring as well as providing protein, energy, vitamins and essential minerals to the human diet. Some are collected and consumed raw while others require complex processing before they can be eaten.
Wild leaves, either fresh or dried, are one of most widely eaten forest foods. Typically they are used as a base in the soups, stews, and relishes which traditionally accompany a carbohydrate staple. This combination is important because as well as providing nutrients these wild leafy vegetables add flavour to otherwise bland foods, and encourage greater food consumption.
The nutritional value of leaves varies widely. Some of the most nutritious, such as the baobab, contain up to 13% protein. Others are good sources of Vitamin A, Vitamin C, calcium, niacin, and iron. Although unusual, the leaves of some species also contain substantial quantities of fat - for example, Bidens pilosa (22.5%) and Dracaena reflexa (18%).
Leaves are an important part of traditional diets in many parts of Africa. In Upper Shaba, Zaire, for example, it was found that leaves from 50 different tree species were eaten (Malaisse, 1985). Wild leaf vegetables are the most frequently consumed wild plants in Swaziland, according to another study, with 48 different species being commonly used. More than half the adults interviewed reported they ate wild leaves at least twice weekly when they were in season (Ogle and Grivetti, 1985). While another study found that in Lushoto, Tanzania, wild leaves are eaten at nearly a third of all meals (Fleuret, 1979).
Boiling fresh leaves in stews is the most common cooking method. Some leaves, however, are dried and powdered. In parts of Senegal, powdered baobab leaves are eaten with couscous. In other cases leaves may be fermented as a means of preservation. Cassia obtusifolia leaves, for example, are fermented and used as a high-protein meat substitute, called 'kawal'. The fermented leaves are made into a paste, or are dried and powdered. Kawal is used in stews and soups which accompany a sorghum porridge (Direr, 1984).
Seeds and Nuts
Seeds and nuts generally supply calories, oil, and protein. Edible oil consumption is low in many developing countries, and oil is often one of the major household food purchases. Low fat diets are thought to be detrimental, especially for children who need energy-dense foods. Fats and oils are also important for the absorption of Vitamins A, D, and E.
From the point of view of nutrition, the most important nut-producing species are coconut palm, oil palm and babassu palm. Coconuts are of central importance in many cultures; on a world scale, they represent 7% of total fat consumption. Other widely-eaten species include the sheabutter nut, cashew nut, and mongongo nut (Ricinodendron rautanenii).
In many parts of the Sahel, the seeds of Parkia biglobosa form an integral part of the diet. In this region, fermented Parkia seeds, or 'dawadawa', is an important ingredient of the side dishes, soups, and stews made to accompany porridges. The fermentation process improves the digestibility of the protein and increases the vitamin content, producing a highly nutritious food rich in both fat and protein. In parts of Northern Togo, fermented Parkia seeds are eaten almost every day (Campbell-Platt, 1980).
There are hundreds of species of wild fruits used worldwide. They are mostly eaten raw as a snack food, although some, such as Artocarpus communis (breadfruit), are dietary staples. Many fruits provide a useful source of minerals and vitamins. The fruits of Ziziphus jujube (var. spinosa) are one exceptional example; they contain seventeen times as much Vitamin C per unit weight as oranges.
Rural people are often familiar with a wide range of different fruits. Studies in Swaziland identified 110 edible wild fruit species, of which 13 were eaten frequently by more than a quarter of those interviewed. It was noted, however, that there was considerable variation in fruit abundance and consumption between ecological zones. There were also differences in the amount consumed by different family members; children generally ate the most (Ogle and Grivetti, 1985).
Roots and Tubers
Roots and tubers provide carbohydrates and some minerals. They are used as drought and famine foods not only because they can survive under reduced precipitation, but also because they themselves can be an important source of water. They are also consumed as snacks by children, herders and others who rely on "bushfoods" during the working day. Roots and tubers are also used as ingredients in traditional medicines.
Many roots and tubers require lengthy processing, usually soaking and cooking, in order to be edible. This probably accounts for their use primarily in times of food shortage. In recent years, however, the availability of food aid and commercial supplies may have reduced their importance as a famine food.
Roots and Tubers
Mushrooms are favourites in many cultures, and are often consumed as meat substitutes. They are good sources of protein and minerals. In one study in Upper Shaba, Zaire, the average protein content of 30 types of edible mushrooms was found to be 22% of dry weight. Here, mushrooms are gathered by women and children, who frequently spend up to two or three hours a day gathering them in the rainy season. The mushrooms are then often marketed (Parent, 1977). Similarly, in the Mae Sa valley in northern Thailand, many species of mushroom are collected in the rainy season for consumption and sale (Jackson and Boulanger, 1978).
Gums and Sap
Certain types of tree sap can be tapped and made into beverages, which are often high in sugars and minerals. Gums are also used as food supplements and can be good sources of energy. Both saps and gums have many medicinal uses.
In northern Brazil, the Babassu palm is used for making palm wine. The stumps left after harvesting are hollowed out and the sap which collects in the hollow is left to ferment (May et al, 1985a). Similarly, the Palmyra palm (Borassus flabellifera) is widely cultivated in southern India for its sap, or toddy. The sap is tapped from unopened inflorescences, each one yielding up to two litres of sap a day. The sap is either drunk fresh or left to ferment, becoming palm wine.
The Babassu palm used for making palm wine
The gum of Sterculia sp. is used as a dietary supplement by the Wolofs of northern Senegal. It is added to soups and stews, and is a good source of Vitamins A and C (Becker, 1983). Similarly, gum arabic produced from Acacia senegal is traditionally an important food for pastoralists, agriculturalists, and hunter-gatherers Nomads from Mauritania use it to make N'dadzalla, a mixture of fried gum, butter, and sugar. It is also used as a milk substitute when mixed with sugared water, and is often the staple food for gum collectors in the field (Giffard, 1975).
3.1.2 Food from wild animals
Forest wildlife is the second main category of food derived from the forests. For communities living in the vicinity of forests, natural woodlands and forest fallow areas, wild animals often play a significant part in local diets; in some cases they provide the single largest source of animal protein.
Discussion of food from wildlife has tended to focus on the large game species such as antelope and deer. In fact, in terms of their contribution to the daily diet, these are rarely the most important species . In many areas large game animals have become rare or inaccessible (as they are protected by hunting bans). In addition, their meat is often difficult to preserve.
Much more important are the smaller wildlife species. These include rodents such as the grasscutter, or cane rat (Thryonomys swinderanus), and the giant rat (Cricetomys gambianus), both of which are highly popular in parts of West Africa. Squirrels, porcupines, bats, mice and other small mammals are also eaten, together with birds and various types of insects, snails, snakes and other reptiles.
Practices and local preferences vary greatly from place to place. In some West African communities, for example, children herding livestock remove ticks from the cattle and roast them for food. In other cultures, ticks will not be touched. Elsewhere, people regard frogs as a delicacy, while others would not dream of eating them.
It is difficult to calculate the extent to which wild meat contributes to local diets. Hunting of large game animals is often carried out illegally, and many of the more commonly consumed foods, such as snails and insects, tend to be eaten as snacks, with the result that their consumption goes unrecorded.
Some of the most detailed information on bush meat consumption comes from West Africa, where people 's reliance on wild animals for food is exceptionally high (in part because it is in the tsetse fly zone). Consumption varies greatly depending on the conditions of wildlife resources. In areas of Nigeria with no reserve forests and high population density, one study found that bushmeat contributed only 7% of the total meat consumed. But in areas near large forest reserves bushmeat provided up to 84% of the total meat consumed. Similarly, in Cote d'Ivoire, it is estimated that 70% of the meat consumed by people in the tropical moist forest zone is bushmeat; whereas, nationally, it only provides about 7 % of the total animal protein intake (Ajayi, 1979).
Springhare is a popular bushmeat in Botswana, some pastoralist communities are estimated to get 80% of their animal protein from wildlife. According to one study, total consumption of springhare is equivalent to the amount of meat obtained from 20,000 head of cattle (Butynski and von Richter, 1974).
In Latin America, wildlife still provides an important source of animal protein in some forested areas. Surveys carried out in the Peruvian Amazon between 1965 and 1973 found that rural inhabitants obtained more than 85% of their animal protein from wild animals and fish (Dourojeanni, 1978). Farmers in northern Brazil's babassu palm region also rely to a considerable extent on hunting for animal protein. The babassu palm fruits are important foods for two large rodents, the paces and the agouti. Stems of fallen palms are also left in situ in order to attract beetle larvae, which are then gathered and cooked.
As a source of protein and vitamins, most wild animals are comparable to domesticated livestock. Some wild species, however, including various rodents, iguanas and pheasants have a higher protein content. Wild meat also tends to have less fat than domestic meat and can be a good source of iron, Vitamin A and Vitamin B.
Some insects are particularly nutritious. Bee larvae, for example, contain 10 times as much Vitamin D as fish liver oil, and twice as much Vitamin A as egg yolk (Mungkorndin, 1981). Some caterpillars are also very nutritious, and have been likened to vitamin pills (Poulsen, 1982).
Besides providing food, wildlife also represents an important source of income for many families. In sub-Saharan Africa there is a long tradition of trade in bushmeat between rural areas and the major towns, where it is sold as a high-priced delicacy. There are well-established trading links stretching from the hunter at one end, through the processors and transporters, to the retailers who sell the meat to urban consumers. In parts of West Africa, snail collection, preparation and marketing is also big business. Districts blessed with snails look forward to the snail season and the harvest it brings.
Commercial ranching and farming of wildlife for meat and other animal products has been attempted in China, Zimbabwe, Thailand and a number of other countries, in some cases with considerable success. Indigenous game species are often better adapted to local environmental conditions than introduced livestock, particularly in arid areas, and are thus more efficient meat producers. By mixing game species with different grazing habits together, or by combined ranching of game with livestock, it may be possible to make better use of the available vegetation than with a single species. The fact that game farming can be integrated with tourism is another potential advantage.
Some wild animals play an additional role in facilitating the production of food from trees and agricultural crops, through their action as pollinators and as natural predators of insect or rodent pests. By maintaining a proportion of forest cover within farming areas, and providing a habitat for wildlife, the agricultural benefits gained from animals can be preserved at the same time as ensuring a convenient supply of wild food.
Obviously, there may be trade-offs involved. Trees near fields, for example, may be a distinctly mixed blessing to a farmer if they are providing a haven for hungry, seed-eating birds. But in other cases, species such as the grasscutter, which would be a pest if their population was allowed to increase too far, can become a valuable source of food when numbers are kept under control through hunting.
3.2 Food producing trees on the farm
3.2.2 Cultivated food-producing trees
Within settled agriculture, the most widespread direct contribution of forestry to food production is through food producing trees on farm and fallow land and around the home. The extent of this contribution varies widely. It should be noted at the outset that the boundary between forests and farm lands in many regions of the tropics is not clear: often forest food trees are selectively left in farm and fallow areas. At one end of the spectrum are the sophisticated 'homegardens' found in many parts of the humid tropics, in which food producing trees provide a major input to local diets. At the other is the single mango tree, or other fruit tree, planted outside the house.
Food producing trees on the farm
3.2.1 Home gardens
Home gardens are defined as "land-use practices involving deliberate management of multi-purpose trees and shrubs in intimate association with annual and perennial agricultural crops and livestock within the household compounds; the whole crop-tree-animal unit being intensively managed by family labour" (Fernandes and Nair, 1986).
Home gardens are found in most ecological regions of the tropics and sub-tropics, although the majority are concentrated in the lowland humid tropics. Population densities are generally high in areas where home garden appear; the average size of a home garden is usually less than one hectare.
Figure 3.1 Schematic representation of the structural composition of a Javanese homegarden.
One of the best known cases is the Javanese home garden, which is schematically presented in Figure 3.1. These provide an excellent example of the diversity and complex structure and function of tropical home gardens. They have been producing sustained yields for centuries in an economically efficient, ecologically sound and biologically sustainable way.
As a general rule, it is fruit trees such as guava, rambutan, mango, and mangosteen that tend to dominate the Asian home gardens, along with other food producing trees such as Moringa sp. and Sesbania grandiflora. In West African compound farms, Moringa sp. is common along with other trees that produce leafy vegetables, as well as trees with fruit for cooking and condiments that are the most important food producing tree species.
Food production is the primary function of most home gardens, and much of what is produced is consumed by the household. When the tree and other food-producing components are added together, home gardens can supply a substantial fraction of a family's food needs. It is estimated, for example, that Javanese home gardens provide more than 40 per cent of the total calorific intake of farming communities in some areas (Terra, 1954; Stoler, 1975).
Another important feature of home gardens is their ability to produce food throughout the year with relatively low labour inputs. Crops with different production cycles and rhythms are combined to provide a year round supply of foods. Although there are peak and slack seasons for particular products, systems are designed so that as far as possible there is something to harvest every day. Any marketable surplus helps provide a source of income between harvests of other agricultural crops, and a safeguard against crop failure.
3.2.2 Cultivated food-producing trees
Much more common than full-scale homegardens is the practice of growing a few food-producing trees and shrubs around the home and on the farm. This happens almost everywhere there is settled agriculture, although the numbers of trees grown varies from family to family and from place to place.
Because it currently falls outside the mandate of most forestry and agriculture departments, tree growing on the farm is very poorly documented. In terms of nutrition, however, the fruit, nuts, edible leaves and other foodstuffs produced often supply an important input to local diets. They also provide a source of income.
Table 3.1 : Profiles of important food producing species in the tropics
Table 3.1 : Profiles of important food producing species in the tropics (continued)
|Species||Ecozone/ distribution||Management||Functions/ uses||Common agro- forestry system/ practices involving these species||Other remarks|
|Areca palm or betal palm Areca catechu L.||Up to 900m, mainly in s Asia, tropical rain forest zones preferred||Propagation by plant- ing one-year seedlings 2.7m square planting, also in hedges, about 1300 plants/ha, bear- ing in 5 yrs, up to 60 yrs, responds welt to manuring||Seed as a manticatory, edible heart, leaves for thatch in some places, leaf sheath for hats, containers, trunk for wood, seeds also used in veter- inary medicine||Cultivated as sole or with other crops usually mixed with cacao and other shade-tolerant perennials, also in gardens and tree gardens||The crop is not suitable for marginal areas and places with long dry spells|
|Breadfruit Artocarpus altilis Fosberg||to Potynesia, grown all over hot humid tropics, especially in Asia and the Pacific||Propagated vegetat- ively by root cuttings usually no seed setting, planted 8-10m apart, grown rapidly, bears in 3-5 yrs, needs little care||Mainly grown for edible fruits pro- duced all year round, 700 fruits/ tree/yr, fruits very vegetable or cooked, biscuits also made, timber useful for farm uses||Usually grown mixed with a large number of other spp in homesteads, yams usually trailed on trees, otters shade for livestock and crops like taro||Sometimes a staple food in Pacific Islands and the Seychelles|
|Cashewnut Anacardium occidentale L.||Widely distributed in tropics Brazil, India, East Africa||Seed propagation, seeds sown at stake, vegetative prop by layering or grat- ting, about 10mē spacing, usually very little aftercare, bearing in 7-10 yes, up to 50 yrs||Highty priced kernels used in confections and desserts, shell- oil has several indus- trial uses, cashew apple is juicy and edible, used for wine making, firewood||Cattle grazing under cashew in plantations, gardens in small holdings, also in home gardens, used as wind- break and shelterbelt||A very drought- resistant tree, non- synchronized flower- ing and difficulty in collecting nuts are main problems|
|Coconut palm Cocos nucifera L||Coastal areas of the tropics, Philippines India, Sri Lanka, Malaysia, etc.||Propagation by trans- planting one year-old seedlings, about 175 palms/ha square or triangular planting full bearing from about 8 yrs and con- tinues up to 75 yrs responds well to manuring||Edible oil from copra (dried endosperm), fruits, drink, leaves for thatch and weav- trunk for wood, many minor products, acclaimed as "Tree of Haven"||Many types of crop combinations in small- holdings, intercropp- ing, and multistorey cropping, also grazing under under in the Pacitic Islands very common||Most widely culti- vated pal- alone or annual or perennial crops, numerous types (the and tall) and cultivated|
|Date palm Phoenix dactylitera L||Grown mainly in Arab countries, India, N. Africa Mexico||Vegetative propagation by basal exillary shoot (suckeres), many named cultivars based on fruits quality Female flowers artificially pollinated||Edible fruit 20-100kg/ tree/yr Sap Sap wine, leaves for thatch, weaving trunk for wood, many minor pro- ducts, shelterbelts and for sand dune fixation||Grown as overstorey species in oasis and other arid regions, large no number of crops grown under neath||It is said to have about 800 about uses|
|Kola nut (Cola nut) Cola nitida (Vent ) Scott and Endl||Mostly in humid West Africa, also in West Indies, India,Brazil||Propagated by seeds, germination in 7-12 weeks, growth is in flushes, fruiting in 7 years fruiting up to 80 years, fruits harvested by using knives at tip of long poses||Seeds used as stilmu- Lants and beverages, average yield 250kg/ tree but much higher yields reported Seeds contain 2% caffeine and some essential oils||Interplanted with fruit trees in young ages and with other tree species in adult stages||Fruit is erroneously called "nut"|
|Mango Mangifera Indica L.||Native to India where very popular but also in S E Asia, Africa and tropical America||Propagated by seed or Layering and grafting, pruning for shape and induce flovering branches, full bearing in about 8 yrs bearing continues up to 50 years and more, several cultivars and hybrids||Fruits very delicious dessert, immature fruits in chutneys and pickles, also ripe fruits as preserves, branches for farm construction, timber as firewood, used in dyes||Grown in association with other fruit trees in the backyard, good as border/shetterbelt species cattle penning in the shade, animal feed or forage||Several associations and types are popular, used extensively on the landscape in India, East Africa|
|Mangosteen Garcinia mangostana L.||Southeast Asis Attempts to introduce to other countries unsuccessful||Seed propagated, seeds have low germi-- nation and poor via- bility Veg prop not successful Requires shade when young Bearing in 10-15 yrs up to 50 yrs 500-600 fruits/ tree/year||A preferred, delicious fruit, eaten fresh Shell rich in tannins, used for leather tanning and medical purposes||Usually grown mixed with other fruit trees and in home gardens||Tendency to bear only in alternate years, difficulty to propa gate, long juvenile phase|
|Shea butter tree Butyrospermum. paradoxum (Gaertn f) var parkii||Abundant in Central and Vest African savannas||Usually propagated by seed, transplanting difficult, about 8m spacing starts bearing in 12-15 yrs fruit falls naturally and is then collected||Shea butter extracted fro- the seed is used as a coooking fat, illuminant medicinal ointment, shea oil trot nuts is used in soaps, candles, cosmetics||Grows in mixed stands with other species in the drier margins of savana with pronoun- ced dry seasons||Its cultivation is not labour intensive|
|Tamarind Tamarindus indica L||Native to dry parts of Africa, now populat all over Africa, India||Propagated by seed, needs very little care, starts bearing about 10 yrs lasts for several decades, fruits are collected fro- tree or alloyed to fall||Fleshy menocarp is Eaten fresh or pres- erved in syrup, seeds eaten as nuts, used as condiment and flavouring also pro duces gums and tannins, firewood, timber good for furniture, foliage and seeds are animal feed||Grows is as an overstorey species in many agri- cultural lands, light canopy and nitrogen fixation are advantages||Grows wildly in drier savannas of Africa and all over India|
There is a great range of tree and shrub species grown for food. Some, such as mango and papaya, are popular throughout the tropics. Others are more localised and are only found in certain specific geographic regions. For example, rambutan (Nephelium lappaceum) is common in south-east Asia, while pejibaye (Bactris gasipaes) is popular in Central and South America (Nair, 1984b). A summary showing the characteristics, management requirements and distribution of ten of the most widely grown species is given in Table 3.1.
Many food-producing tree and shrub species have multiple uses. Besides providing food, they may be valued for shade or for their gum and tannin extracts. Leaves may be used as fodder or green manure, or to provide materials for thatching and handicrafts. Wood suitable for construction and furniture making can be obtained from certain trees, and almost all provide a certain amount of firewood in the form of twigs, prunings and dead branches.
In some cases these uses are non-competitive. In other cases the protection and care afforded to many food-producing trees is a measure of their importance and perceived value to local people. The cutting of a prize fruit tree for fuelwood or timber is unusual; where it happens it is often a sign of severe wood scarcity, or it is because the family needs to raise cash for a major purchase or unforeseen expense.
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