Chapter 2

Wild plants in various farming systems

Farm households that use wild plants vary enormously in their size, composition, area of land, form and organization. They include small-scale subsistence and infrasubsistence farmers with small parcels of land, swidden or shifting agriculturists, cattle ranchers, extractivists, nomadic pastoralists, pastoralists, agropastoralists, village-based communities, farmers of forest gardens, home gardens, tree orchards, terraces and so on. The magnitude of the contribution of wild plants to their economy varies enormously as well. Different patterns are found in areas, regions and countries, and even among villages within the same area, corresponding to their characteristic social, cultural and historical background.

Each system has its own characteristics and has to be treated separately.

SHIFTING CULTIVATION

Traditional shifting cultivation, also called swidden, Jhum or slash-and-burn agriculture, is a low-intensity system of agriculture practised by many collectors of non-timber forest products. It is characterized by:

• the controlled use of fire to clear small plots of land;
• burning much of the vegetation;
• leaving the tree stumps standing to avoid unnecessary soil disturbance;
• cultivating a mixture of crops for two or three years with a minimum of tillage;
• fallowing on a rotating basis to allow restoration of soil fertility and succession to forest;
• frequently managing the fallow for crops and wild species and to encourage succession to forest.

Shifting cultivation has been in use for thousands of years and is found in many parts of Asia, Africa and Latin America today. Such a system of cultivating a plot of land for a few years and leaving it under fallow for a much longer period creates a mosaic of vegetation under different successional stages, and the plants in the secondary regenerated forest are often exploited by the farmer. Shifting cultivation in fact comprises an array of highly variable and site-specific systems that have developed in response to local environmental and socio-cultural conditions. A wide range of crops are grown - as many as 100 or more at any one time, including food crops, medicinal plants, spice plants, weaving plants and drug plants, many of them semi-domesticates. Stands of wild timber trees in and around the swiddens are often preserved to serve as a seed reservoir for the regeneration of new secondary forest.

Shifting cultivation systems, like most home farms, typically generate very little surplus of production above and beyond the needs of cultivators themselves. It is therefore a system suitable only for autonomous, small-scale societies.

Recent work has shown that swidden fallows are not just abandoned but are managed in some areas; the management involves planting and protection as well as making use of some of the wild species that appear at various stages of succession. In Southeast Asia, for example, some wild and feral species in swidden fallows are protected and harvested. In New Guinea, a study of the Wopkaimin showed that up to 40 species that appear spontaneously in fallows are used as food or for other purposes, while other studies indicate that in Thailand and the Philippines several hundred plants in swidden fallows may be used.

In a detailed study of fallow manipulation in zones of settled forest known as te'lom (selva manejada - managed forest - in Spanish) by Huastec Indians in southeastern San Luis Potos� and northern Veracruz, Mexico, it was reported that 33 plants were used for construction, 221 as medicines, 65 for various utilitarian purposes, several for livestock food and 81 for human food (Alcorn, 1984).

AGROFORESTRY AND HOME GARDENS

Agroforestry involving wild or semi-domesticated species to a greater or lesser extent is one of the commonest systems of sustainable management and land use practices employed by traditional societies in the tropics. In its various forms, agroforestry combines agriculture, sometimes with livestock raising, with tree crops and the use of wild forest plants on the same land. All agroforestry systems share the following characteristics (Winterbottom and Hazlewood, 1987):

• the deliberate association of trees and shrubs with crops, livestock and other elements of agricultural production;
• readily identifiable (although often complex) ecological and economic interactions between the trees and shrubs and the other elements of the production system;
• at least two or more outputs from the system, with some of the production cycles extending beyond one year.

Four main types may be recognized: agrosilviculture, silvipastoralism, agrosilvipastoralism and home gardening (see Box 1).

In Mexico peasant agriculture or agroforestry is practised by 88 percent of farmers on 57 percent of the country's agricultural lands and relies primarily on farm household labour. Within this peasant agricultural sector, infrasubsistence farmers make up 45 percent of the producers in tropical Mexico. Typically their parcels are less than 4 ha. Small-scale producers play an important part in export crop production in the humid tropics: 60 percent of Mexico's coffee plantations are between 1 and 5 ha, with coffee plantations of this size accounting for 31 percent of total coffee production. Likewise the average size of cacao farms in Tabasco is less than 3 ha, the parcel size depending on availability of family labour. All peasant agriculture depends to some degree on wild plants gathered from non-cultivated areas, although less successfully than in pre-Hispanic Mayan agricultural systems.

Many of the Mayan methods of agriculture are still in use today. Mayan agroforestry comprises the protection, cultivation, selection and introduction of trees in the milpas (maize fields), fallows, plantations, natural forests and forest gardens, as well as protected forest networks along trails. One of the striking characteristics of present-day Mayan towns is the abundance of useful trees in their home gardens. These home or forest gardens are a traditional agricultural system providing shade, fuelwood, food and drink, medicine and fodder (see Box 2).

Home gardens or similar agroforestry systems under different names (yard gardens, kitchen gardens, etc.) are found in most tropical and subtropical regions of the world (Fernandes and Nair, 1986; Anderson, 1993a, 1993b; Ortega et al., 1993).

It has been estimated that nearly 1 000 million people in the tropics live from the produce of 5 million home gardens supported by subsistence agriculture. The essence of such systems is the diversity of species they contain, their architecture and physiognomy. Typically they contain a number of different strata; up to four have been recorded. Figure 2 illustrates a typical Cuban home garden or conuco.

Families seldom depend on home gardens completely for their major subsistence, and in some cases their contribution is minimal. For example, in the Amuesha yard gardens in the Peruvian Upper Amazon, the number of species in a single garden ranged from none to 26. The households with the most crops in their gardens depended on them for a certain percentage of their subsistence diet; their fields had low crop diversity and they relied on what the gardens produced. The next group, with slightly less diversity in their gardens, had a greater diversity in the fields and used the gardens only for more specialized crops. Households with no tenure rights to their land saw no reason to plant fruit-trees when other families might take over their land before the fruit became ripe. Families dedicated to raising cattle and using wage labour said they had no time or interest in growing fruit (Salick and Lundberg, 1990).

A remarkable development of complex home gardens is found in Java, where rural families have depended on home gardens for centuries. Javanese home gardens show great diversity: in a study of 351 home gardens in western Java, up to 501 species were recorded. The gardens are estimated to provide households with about 14 percent of their total carbohydrate and protein consumption.

Not only do home gardens of different types in different countries vary widely in form, structure and composition, but home gardens also vary among themselves in their purposes and the produce they provide. Among their roles are provision of nutrition, dietary supplements, food security in times of crisis, shade, fuelwood, cash income, experimentation, aesthetics, medicinal plants and small-animal raising.

Over two-thirds of India's 850 million people depend on agriculture for subsistence. They are small farmers and landless labourers, tribal people, shepherds and artisans who are closely and intimately related to their local ecosystem. The bulk of implements, carts, boats, fencing and construction materials are obtained locally. These village farming systems consist typically of cultivated land, clusters of houses, tracts of non-cultivated lands, village common lands, irrigation channels, farm bunds, house yards and rural roads, all of which have traditionally supported a large number of species.

Throughout much of India species of Ficus (fig) have been regarded as sacred and protected (see Box 3). They and other trees such as jamun (Syzygium cumini), neem (Azadirachta indica) and leguminous trees such as Prosopis and Acacia species are also important components of the landscape in many parts of the country. Not surprisingly, India, where a wide range of living organisms are put to use, has been called a biomass-based civilization. In a study of 82 villages in semi-arid zones of seven Indian states, it was found that biomass harvests from common lands provided between 14 and 23 percent of household income from all sources (Jodha, 1990).

PASTORALISM AND AGROPASTORALISM

The oldest and most extensive use of wild plants by farming households is indirect, through grazing or browsing of plant biomass by domesticated animals. The range of types of grazing land in both temperate and tropical countries is large, and each type has been classified in numerous ways. The main vegetation types are:

• tropical grasslands or savannahs in the drier tropics and subtropics in which grasses form a conspicuous ground cover, often with shrubs and trees present resulting in woodlands, open parklands or dense scrub, e.g. cerrado, llanos, caatinga, bushveld, mulga, brigalow, highgrass-low tree savannah, acacia-tallgrass savannah, acacia-desert grass savannah, campo limpo, campo cerrado;
• temperate grasslands where the seasonal climate favours the dominance of perennial grasses, e.g. the prairies of North America, the steppes of Eurasia, the pampas of South America;
• arctic and alpine grasslands or tundras characterized by tussock grasses, sedges and, in favourable conditions, shrubs.

Each type has its own structure, characteristics, ecology and floristic composition. The grasses and non-graminoid herbaceous and woody species that are exploited by grazing and browsing animals in the grasslands are too numerous and diverse to be usefully summarized. Many grasslands have been invaded by exotic species which pose a threat to the native species, and introduced pasture species have also replaced large areas of native grassland. A major review of tropical grazing lands can be found in the state-of-knowledge report Tropical grazing land ecosystems (UNESCO/UNEP/FAO, 1979).

Apart from the key role of wild plants as grazing and fodder, many of the species of the different types of grasslands are used by pastoral and agropastoral farm households for food, fuel, construction, medicine and veterinary medicine. They may even provide some cash income, especially in pastoral areas with trees.

Tree products in dryland pastoral communities include various exudates such as gums and oleo-resins, for example gum arabic from Acacia senegal and other species in the Sudan and other parts of Africa south of the Sahara and gum tragacanth from Astragalus species in the Near East. An important group of plant products in the Arabian Peninsula are the oleo-gum-resins from species of the genera Boswellia and Commiphora of the family Burseraceae. These are produced in resin ducts in the bark and give rise to the resins frankincense and myrrh. Boswellia sacra, the most celebrated plant of Dhofar, Oman, played a key part in its economy until recent times. Three species of Commiphora are used medicinally in preparations made from their resiniferous wood or from the resins themselves: C. gileadensis (=C. opobalsamum), the famous balm of Gilead (Mecca myrrh); C. foliacea; and C. habessinica, whose resin is of most value medicinally. Yemen's island of Socotra likewise was formerly a major source of gums and resins, largely from Commiphora and Boswellia species but also from Dracaena species, the source of dragon blood of medicinal as well as other commercial value. Although the trade in these resiniferous woods and resins has declined considerably, they still have a role locally and are used in Western herbal medicine for a variety of complaints. A detailed review of the developmental potential of these species would be useful.

MANGROVE SWAMPS

Mangroves, characteristic littoral plant formations of sheltered tropical and subtropical coastlines, represent a major economic resource which is increasingly being destroyed as a result of human activities. The economy of coastal communities living in or near mangrove areas is dependent to a greater or lesser degree on the goods and services they provide: harvesting of fish and shellfish, timber for construction and shelter, fuelwood and other minor products. Box 4 lists the major plant products of mangrove ecosystems.

EXTRACTIVISM

Another important and widespread use of wild plant resources is through various forms of extractivism, which has been defined as the systematic exploitation of forest products that are intended for sale on regional (within a country), national or international markets (Lescure, Pinton and Emperaire, 1994). It can be divided into two main sectors, timber and non-timber products, the latter widely known as non-timber forest products (NTFPs). Timber provides by far the greater part of the total value of extractive production, with figures of over 80 percent in the Brazilian Amazon.

Non-timber forest products may be defined as all biological materials other than timber that are extracted from wild or semi-domesticated sources in forests for human use. They are also known as non-wood forest products. The term usually includes specialized wood uses such as tool handles, carvings and medicinal uses. Some authors also include ecosystem services such as soil and watershed protection, carbon sequestration and climate moderation in calculating the values of NTFPs. A list of major NTFPs is given in Box 5. These overlap, as would be expected, with the main usage categories for wild plants given below in Chapter 3 (Box 6).

Extractivism has been particularly studied in the Brazilian Amazon (see Table 1), where it is one component of a rural economy that combines various types of activity. Thus a productive family unit combines subsistence agriculture with extractive and fishing activities. Some of the products are consumed within the domestic unit while others are destined for the market (Allegretti, 1994). Mat� tea and cashew nuts are the leading food products and other important ones include Brazil nuts, cabbage palm fruit and palm hearts.

TABLE 1

Principal extractive products derived from native plant species in the Brazilian Amazon

Source: Lescure, Pinton and Emperaire, 1994.