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Functions and significance for development

Photo 6. Bunds planted with Leucaena leucephala in Cape Verde. (© Bellefontaine/Cirad

Trees outside forests, a fundamentally multipurpose resource, are more intimately linked to the society around them than forest trees. Their productive, ecological and cultural functions are incisive, and their social, economic and environmental roles help to sustain households and household income. They are instrumental in national and international economies. They promote the conservation and sustainability of tree resources. A review of their role in peasant income acquisition strategies and potential value as economic and market indicators constitutes a challenge and innovation in the approach to forestry.

A multi-purpose, multi-use resource

All trees can be described as potentially multi-purpose, but the potential uses of Trees outside forests are more clearly evident. The wealth and diversity of their uses and services create a permanent, daily interaction with people that can be seen in production and research strategies, as in
Income mobilization.

Trees outside forests, which may be spontaneous or planted, are usually cultivated and tended by people. They may be exotics, or perhaps species domesticated and bred by local populations (Box 5).

Shade and shelter, environmental protection, and enhancement of rural and scenic surroundings are the main reasons cited by industrialized country farmers for leaving trees standing in their fields (Auclair et al., 2000). In the developing countries, however, farmers are particularly apt to favour, select and plant species which can offer a range of goods and services. This is the best way of managing land, labour and capital (Arnold, 1996). The babaçu palm tree in northern Brazil has long been part and parcel of the shifting cultivation system (May et al., cited in Arnold, 1996). In Vanuatu, trees are highly protected as biological diversity shrinks (Walter, 1996). Where species are few or rare, people tend to tap a wide range of potential products, whereas potential uses tend to remain dormant in a more diversified environment (ibid).

Trees outside forests represent a major food source for rural populations. Parklands of néré (Parkia biglobosa) and shea-nut (Vitellaria paradoxa) are maintained because of the food items they offer (such as pods and nuts used as condiments or butter). People in West Africa consume an estimated annual ten kg of shea-butter per person (Boffa, 2000b). Date palms are valued for their fruit in Iraq, not to mention shade and crop protection. In sub-Saharan Africa and in the Sahel, the pericarp of the fruits of the doum palm (Hyphaene thebaica) and of Boscia senegalensis are crushed to provide a meal that can stand in for cereal grains when food is short (Bernus, 1980). Trees outside forests have also been called "trees that nourish" (Bergeret and Ribot, 1990) (Box 6), a term which is really meaningful for landless people who make beneficial use of the tree products to which they have access. Women, the first to be concerned by this harvest, possess the skills to store and process these leaves and fruits so that they will be on hand to feed the family all year round. A study done in Java showed that 60 percent of the family's food comes from home gardens in which trees are prominent, and that these gardens are mostly managed by women (FAO, 1989).

Box 5:

Selection of local or exotic species

Most of the 40 or 50 tree species cultivated in home gardens in Tanzania are indigenous (Banana et al., 1999). Exotics may predominate in other countries, as in Kenya, where very few local species (10 percent of the total) are actually planted. Diversity among the exotics depends mostly on the number of species proposed by the agricultural and forestry services, reflecting the range of species which grow well in forest nurseries. In Burundi, exotics predominate on farms (Eucalyptus, Grevillea) as in shelterbelts and windbreaks for grasslands. The prevalent fodder trees in Uganda are Leucaena leucocephala and Sesbania sesban (ibid.). In Mauritania, Prosopis juliflora is planted to forestall the advance of sand dunes around oases threatened by sand intrusion (Selme, 1999).

Box 6:

Diversity of rônier products

It is said of the rônier (Borassus aethiopum) that no part of the tree is wasted. The kernel and mesocarp of the fruit are eaten. The jelly-like, immature fruit is delicious, and a decoction of the roots makes a cooling drink for infants. The sprouts are prepared as a vegetable. The sap is used to make wine. The bole provides high-quality wood. The leaves are suitable for weaving roofs and fences. Furniture is made from the leafstalks, which also provide fuel. The ribs of the leaves and roots are ideal for weaving mats, nets, rope and baskets. The hulls of its seeds are used in craftwork, and the apical buds to tie sheaves of millet and sorghum. The male flowers make excellent fodder. Mixed with shea-butter, they are also used to treat skin irritations.

Trees outside forests not only provide products that enhance food security, they also help to promote dietary balance, diversity and good health. Tamarind (Tamarindus indica) fruits are especially rich in Vitamin C. Baobab (Adansonia digitata) leaves, eaten fresh or dried, are a good source of Vitamins A, B, and C, calcium, phosphorous, and iron (Boffa, 2000a). Scoones et al. (1992) underline the importance of edible products from forests or complex agroforestry systems, (the contribution from Trees outside forests is even higher in this respect). All these products may provide simple snacks during work or travel (Ogle and Grivetti, 1985), or, like baobab, they may be eaten when food is short, or, again serve as a basic food, like breadfruit (Artocarpus altilis) or Tahiti chestnut (Inocarpus fagifer) (Walter, 1996). Some Trees outside forests have medicinal uses, with parts such as leaves, roots and bark providing the raw materials for medicinal and veterinary products (Box 7).

The fodder and browse of Trees outside forests are a major source of livestock feed. While such products are fairly untapped in humid zones except in the urban and peri-urban areas of developing countries, they can mean the difference between life and death in arid and semi-arid zones. Livestock owe their continuing good health or survival to tree fruits or leaves to round out or balance the daily fodder ration in many regions of the world. Trees are the only source of green forage during the lean times before the rains. Fodder trees may also be planted or left standing near home where stockraisers no longer have access to specific rangelands, or where there are not enough people to drive the animals.

Trees outside forests provide many other services for livestock. They offer comfort and shelter for animals, such as Pinus radiata windbreaks in New Zealand, Samanea saman and Albizia shade-trees in the sub humid tropics, and the twin rows of beech (Fagus sylvatica) which grow on the Norman slopes in France. Bushy, thorny hedgerows are planted to mark boundaries and channel herd access and movements. Toxic euphorbs (Euphorbia tirucalli, E. balsamifera), and Gliricidia sepium are planted very closely in Indonesia to form living fences, and their clippings used as fodder. The leaves of Hibiscus tiliaceus feed cattle in Vanuatu, and Hawthorne (Crataegus oxyacantha) is trimmed to form thick, impenetrable hedgerows in Europe.

Trees outside forests also play a key environmental role). They mark off territorial boundaries, a first stage in land appropriation, demarcate holdings, decorate living quarters and provide welcome shade for man and beast in the hot countries. Shade trees are beneficial components of coffee, cocoa and tea plantations in some agroforestry systems. Cordia alliodora and Erythrina poeppigiana shade coffee plantations from the sun's glare in Latin America. Looming on the horizon in arid countries, trees are used by nomadic peoples in arid countries as markers. Most place names in Touareg regions make reference to trees (Bernus, 1980).

Box 7:

Pharmaceutical products from trees

Fulani pastoralists in West Africa use the same word, "lekki", for trees and medicines. This revelatory double meaning shows the importance of trees in concocting remedies. All parts of the tree are used: leaves, roots, bark, and so forth. Often the designated item has to be gathered at a specific time of day, a task entrusted to someone of acknowledged botanical and magical skills. African peoples south of the Sahara are well-aware of the many medicinal properties of the néré tree. The bark is used to treat infectious diseases and digestive problems, the leaves to heal wounds and skin diseases, the roots to treat epilepsy, and the pulp to lower fever (Boffa, 2000b; Arbonnier 2000).

Trees outside forests are imbued with symbolic, cultural, and even religious value. They crop up in so many aspects of culture: language, history, art, religion, medicine, politics, and more. Folklore, stories and proverbs also attest to the symbolic significance of trees in human thought (Calame-Griaule, 1980 and Kaboré, 1987, cited in Boffa, 2000b). They are sometimes called "trees of wonder", when due to their venerable age, isolated trees have reached impressive size and girth and passed into local legend3 . Watkins (1998) has shown how such trees are valued in the U.K. for their beauty, solemnity and mystery.

One could go on with the long list of goods and services trees provide, such as fuelwood, raw materials for crafts, tool handles and furniture-making, or wood for housing and shelter. Over a million people live in houses4 either made of bamboo, or which use bamboo as a structural element, wall-panels, or roofing (Kumar and Sastry, 1999). Also worth mentioning are such products as resin, latex or gum Arabic, or again the extraction of essential oils and the production of cosmetic products. The same tree often has several uses - rarely is a species maintained for a single use or product. All parts of the tree are harnessed to make products for a wide range of uses.

Photo 7. Rearing cattle under coconut in Vanuatu - (© B. Toutain)

Trees outside forests: the under-counted economic benefits

This resource furnishes products for direct consumption or processing by rural households, steady income from sales of fuelwood, or windfalls from the occasional log. All represent real market value. Generally speaking, such products are mostly for home consumption, but the proceeds from sales can also tip the balance for small-scale, resource-poor peasant traders (Arnold, 1996) having little contact with formal marketing arrangements. So it is hard to reckon the contribution of Trees outside forests to household incomes. Any statement of the local economic value, profitability, production or consumption of the products of this resource is open to interpretation. The price of any product only partially reflects its true value. This is because production and labour costs are rarely reckoned into the equation.

It is hard to assess the economic contribution of Trees outside forests at the local level and even harder and more complex at national and international levels. Wood and non-wood products from off-forest trees only make it into the statistics when traded on official, national or export markets, and, even here, the statistics fail to differentiate between forest and non-forest products. This is true of gum Arabic, sheanut, cocoa, coffee, tannin, and so forth, a portion of which is produced on small farms (this also exposes the sector to swings in the world market). And while the aggregate amounts produced and their channels may be relatively well-known, the production and resource dynamics are reported either separately or incompletely. This has the effect of masking5 the economic impact of the resource. We can, however, get some idea of this value by reviewing the various benefits of wood and non-wood products in the forest sector.

Box 8:

Trees outside forests: fuelwood production

In the Asia-Pacific area, over two-thirds of the energy demand is supplied by fuelwood from non-forest sources, providing fuel for two billion people (FAO, 1998a). Jensen (1995) sets relative values for the consumption of fuelwood from non-forest sources at 50 percent for Thailand and 75-85 percent for Vietnam, Pakistan, Sri Lanka, the Philippines and Java, Indonesia. Ninety percent of the fuelwood in Bangladesh comes from garden forests (Torquebiau, 1992). A study done in the Indian state of Gujarat showed that the potential productivity of peasant woodlots of Casuarina equisetifolia could go from 4,1 to 11,8 m3/ha/yr (Verma, 1988). In the Sahel, wood energy from fields and forested areas accounts for an average 90 percent of total energy consumption (Minivielle, 1999). One km of coppiced hedgerow in France produces 8-15 steres of wood/yr, the energy equivalent of 1500-2000 litres of fuel (Schmutz et al., 1996).

Wood products


Wood is still the most widely used source of fuel in the developing countries, (Box 8), where wood-based fuel accounts for 81 percent of the wood harvested. The figure for Africa is 91 percent, for Asia 82 percent, and for Latin America 70 percent (FAO 1999a). Indicatively, a family of six in Mozambique consumes an average annual 7m3 of fuelwood, with the aggregate annual fuelwood consumption for a population of 17 million estimated in 1985 at 18 million m3 (Saket, 1998). Now that the population is estimated at 18 million, consumption is presumably around 20 million m3. Traditional fuels (basically fuelwood) account for only seven percent of energy consumption in the industrialized countries (FAO, 1999a).

Box 9:

Agroforestry systems and fuelwood production

Agroforestry systems in Asia are crucial to fuelwood supply. In eastern Java, fuelwood meets 63 pour cent of the energy requirement; and in central Java, 49 to 81 percent (Ben Salem and van Nao, 1981). Trees such as laurel (Cordia alliodora), grown for shade in the coffee and cocoa plantations of Central America, supply both fuelwood and timber during the 10-15 years of their rotation (Somarriba, 1990). Over a fifteen-year period in Paraguay, the average output of a one hectare woodlot of paraiso (Melia azedarach var. «Gigante») was estimated at 110 m3/ha, the wood being used for fuelwood, poles and posts (Evans and Rombold, 1984). In Sudan, forest fallow systems of Acacia senegal, mainly to produce gum Arabic, also contribute fuelwood (Ben Salem and van Nao, 1981). Parkia biglobosa parklands in Mali generate some 0,15 to 0,2 m3/ha/yr of fuelwood (Bagnoud et al., 1995). In Niger under the Master Supply Plan for Niamey, the 2 600 158 hectares of Combretaceae forest plateaux have an annual productivity of nearly 300 000 t. Non-forest farmland representing some 4 million ha produces an additional 188 000 t each year, over 60 percent more (Ichaou, 1993).

Few studies give an aggregate fuelwood production figure for tree stands and Trees outside forests, and even fewer detail the various provenances. Proximity coupled with the ease of of agroforestry system management (Box 9) does make them an attractive and important source of fuelwood. And while it is not the main purpose of orchards to produce fuelwood, that is often an important side effect, especially in the developing countries. Olive tree sanitation, rejuvenation and replacement in Morocco usually accounts for 0.8 to 1.5 m3/h/yr of wood fuel, depending on the climatic zone (M'Hirit and Et-Tobi, 2000).

More surprisingly, Trees outside forests are considered a source of fuelwood in the urban forestry context. In small, tropical, urban areas of Asia and Africa, a fairly substantial proportion of the wood burned is gathered inside the towns (Kuchelmeister, 2000). In the industrialized countries, especially in North America where urban forestry is well-developed, tree residues are under-utilized. A study in the United States showed that only six percent of the 13.5 million m3 of urban woody residue is used as fuel, with three percent sold as fuelwood and three percent burned as fuel, the remainder having no direct utilization (Whittier et al, 1995, a and b). Wood-fuelled power plants have been recently proposed in some savannah or open forest areas in developing countries. Units tapping bioenergy from plant wastes, or perhaps alternating fuelwood and bagasse, have been established in a number of countries, including Nicaragua. These renewable energy sources offer an alternative to fossil fuels. Farmers planting non-forest trees near these power stations are bound to find lucrative outlets.

Timber and service wood

Off-forest tree resources provide service wood for planks, poles, beams, roofing materials, furniture and the like in construction, plus fencing materials and transport items such as wheelbarrows and carts. Timber from trees such as Faidherbia albida and Sclerocarya birrea wood in Mali is also used in local craft industries. Wood from the pehibaye palm (Bactris Gasipaes) is marketed to make parquet flooring in the American tropics (Clément, l989)

Timber is not generally the foremost end product of off-forest tree resources. But there are exceptions to this rule. The figures for timber can be quite high, as much as 70 percent of the supply of construction and industrial wood in Sri Lanka; 84 to 95 percent in the Indian state of Kerala (Krishnakutty, 1990, cited in Mohan Kumar et al., 1994: Sharma, 2000). In Central America, Beer et al (2000) report a potential productivity of 21.8 million m3/yr of sawn logs, assuming effective harvesting of the tree products of shade plantations and some silvopastoral systems. There are also associations of forest industries and small agricultural enterprises for the production of timber and service wood. Wimco Ltd., a match manufacturer in northern India, has driven agroforestry in the region (Newman, 1997), and small farmers in KwaZulu-Natal in South Africa receive support from paper pulp producers (Arnold, 1998).

Non-wood products

Just as many non-wood forest products are harvested from trees in orchards and agroforestry systems as from forest species. The non-wood products of forest species are termed "non-wood forest products"6 . As forest resources dwindle and the need for certain non-wood products mounts, trees growing outside forested areas are increasingly meeting the demand. Yields can be even higher than forest yields (Boffa, 2000, b), as can the income from harvesting timber (Peters et al., 1989). In the early 1990s, this pushed scientists to take a fresh look at the importance of non-wood products, particularly health foods, i.e, natural foods with therapeutic properties, capable of halting or averting the development of certain diseases. These extensively (if informally) traded products are socially and economically valuable. The demand for such products is bound to grow as both the world's population and research in this domain expand.

Non-wood forest products are among the oldest trade goods in the world. In the year 2000 B.C. the Egyptians were already importing gum Arabic from the Sudan for food, paints, gum and for use in mummification (Seif el Din and Zarroug, 1996). Pine resin has been harvested in temperate zones for over 2 000 years (Vantomme, 1998, cited in Taylor, 1999). The trade in sandal wood oil goes back to the twelfth century A. D. (FAO, 1995b).

Non-wood forest products are as essential to industrialized country economies as to developing countries or countries in transition. In the Pacific Northwest alone, the trade in non-wood products, such as ornamental plants, mushrooms, and other edible and medicinal plants, brings in an annual US $200 million, if not more (Hansis, 1998, cited in Taylor, 1999). From 1994-1996 in the Czech Republic, the mean annual value of the harvest of non-wood forest products produced some 2.7 billion koruny7 (Olmos, 1999). China earns about US$ 130 million from the export of edible bamboo shoots (Kumar and Sastry, 1999).

A key factor in the success of non-wood forest products is local processing to preserve them, reduce post-harvest losses, and reach distant markets, all of which add significantly to the value of the resource. These products are important for populations with little or no access to inputs and resources. Minorities or women skillfully gather, conserve and process them as subsistence or trade goods (Box 10). In West Africa, non-wood forest products are primarily in the hands of women traders. In Gambia, for example, half of women's income can come from these products, compared to 25 percent for men (Boffa, 2000a).

A review of products from parts of the tree (Table 2) gives some indication of the potential economic benefits of Trees outside forests, despite the fact that we basically do not now know enough to clearly separate the benefits from forest and non-forest products.

Fruit and seeds

Fruits and seeds are mostly derived from cultivated tree orchards or agroforestry systems. Data and statistics on orchards are accessible because the sector comes under the technical services of agriculture departments and ministries, but the data on agroforestry systems tend to be much more partial or sporadic.

Box 10:

Cameroon: the trade in non-wood forest products

A study on non-wood forest products was conducted by the International Centre for Forest Research in 1995-1996, covering selected markets in the rainforest area of Cameroon. Merchants, mostly women, select one person to be in charge of organizing the market, enforcing local, informal rules, and coordinating informal credit facilities such as tontines. Nine food or medicinal products from eight species (Garcinia kola, Garcinia lucida, Elaeis guineenis, Gnetum spp., Cola spp., Irvingia spp., Ricinodendron heudelotii, Dacryodes edulis) representing 95 percent of the products traded were monitored for 16 weeks (D. edulis fruit), and 29 weeks (all other products). The average weekly profit per person was estimated at 8 200 FCFA8 . The average monthly salary of an urban worker at that time was 6 500 CFA francs (Ruíz Perez et al., 1999).

Fruit trees in the industrialized countries are intensively managed just like farm crops, and are frequently monocropped and genetically improved. The numerical data on production, consumption and yields are ready to hand and fairly reliable. In some developing countries, such as Peru, fruit farms and agroforestry systems set up expressly for the export trade both produce fruit (Kleinn, 1999). Fruit plantations in Brazil cover 2.3 million ha, with citrus plantations alone (mandarins, oranges and lemons) covering one million ha. This system of Trees outside forests supplies over 4 million tonnes of fruits and latex (ibid.).

Fruit production in agroforestry systems is not as structured as the traditional fruit tree cultivation circuits. In traditional home gardens (Box 11), trees and shrubs are grown in association with annual or permanent farm crops plus animal husbandry activities, particularly small animal husbandry. These kinds of systems are found throughout heavily populated areas of the tropics. Multi-purpose trees are preferred. Up to two-thirds of the species used by farmers in Bangladesh are fruit or food trees (Mehl, 19991)

Box 11:

Fruit production in home or village gardens

The attraction of fruit tree cultivation in home or village gardens is primarily due to greater proximity, which means more intensive management, greater density, and higher productivity as compared to fruit trees in forests. A study of açai palms (Euterpe oleracea) in Para, Brazil, in the flood plans of the Amazon estuary showed that fruit productivity rose from 7.3-12.2 t/ha/yr in secondary forest to 13.7-18.2 t/ha/yr in home gardens (Muñiz-Miret et al., 1996). Proximity to a local market also favours sales and enhances the value of fruit production. This is true in Cibitong, 50 km from Jakarta, Indonesia, where several decades ago village vegetable gardens near the capital were turned into diversified fruit orchards concentrating on several commercial products (Mary and Dury, 1993).

Photo 8. Faidherbia albida agroforestry parkland in Burkina Faso (© Depommier/Cirad).

In Sudano-Sahelian Africa, agroforestry parklands, where the presence of trees in fields is regular, systematic, and deliberate, provide fruit for rural populations (Sauter, 1968, cited in Bagnoud et al, 1995). The desert date palm (Balanites aegyptiaca) produces an estimated 100-150 kg of fruit per mature tree each year; jujube (Ziziphus mauritiana) 80-130 kg; and tamarind 150-200 kg (Boffa, 2000a). Shea nut (Vitellaria paradoxa) is outstanding, producing an average 48-65 kg/ha/yr of dried nuts. Shea nut-linked activities can account for some 20-60 percent of the income of women in Burkina Faso (ibid.). Aside from timber and fuelwood, its main value lies in the myriad uses made of its fruit (Bagnoud et al, 1995). The pulp is eaten raw, and the kernel supplies oil used in cooking, cosmetics, candles, and even for waterproofing the walls of farmers' homes. In addition to these local functions, shea nuts are exported for use in cosmetic, pharmaceutical and bakery products, to the tune of 40 000-75 000 t to Europe and 10 000-15 000 t to Japan (Boffa, 2000a). The economic value (the contribution of the resource with respect to production losses to crops) of shea nut and néré parklands is probably about 4 800 -10 600 CFA francs/ha/yr (Boffa et al., 1996). Export income is not accurately known for lack of firm and reliable data, a hindrance to the development and optimization of this resource.

Table 2: Trees outside forests, source of a wide range of non-wood products

Tree parts

Some products

Production systems

Some uses

Fruits and seeds

Fresh and dried fruits, seeds (coffee, shea nut).

Fruit orchards, home gardens, parklands.

Food, cosmetic and pharmaceutical products


Animal fodder, leaves for human consumption

Agrosilvopastoral systems

Feed, food and medicinal uses

Stems and bark

Latex, gum arabic, resin, tannin, fibres Cork, bark products, essential oils.

Plantations, home gardens, parklands Agrosilvopastoral systems

Tires and treads hides and textiles, food, agrofood and. pharmaceutical industries, cosmetics, skins, textiles, wood pulp. Corks, wall coverings, insulation, pharmaceutical derivatives.


Honey, essential oils

Agrosilvopastoral systems

Food, pharmaceutical industries


Beverages, juice

Agrosilvopastoral systems

Alcoholic drinks

Much more is known about coffee and cocoa, products traded in the international market-place. While 85 percent of the world's coffee is consumed in Europe, the United States and Japan (Alvarez et al, 1992), most of it originates in Latin America and the Caribbean (FAOSTAT, 1999, cited in FAO, 2000c). In 1996, coffee accounted for 14.9 percent of Colombian exports, a contribution of US$ 1.5 billion to the 80 billion of GDP. In 1989, coffee exports in El Salvador accounted for 44 percent of value added (in constant prices) within the national economy (Rice and Ward, 1996). The coffee trade in El Salvador generates from 9 to 15 billion US$, depending on world prices and how good the season was. Of this figure, 40-80 percent goes back to the small farmer (Follin, 1999). Coffee production is often a key factor in the economy of these countries.

The same may be said of other permanent crops such as date palms, coconut and cocoa, which are key factors in local development and social structures, drive the economy and vector the entry into world trade (Table 3). These crops not only supply income to local farmers, they offer the added benefit of a crop whose productive life can extend over several generations on a fairly small area, much of it farmer-owned (Follin, 1999). Côte d'Ivoire, for example, produces close to 40 percent of the 2.9 million tonnes of cocoa traded on the world market (FAOSTAT, 1999, cited in FAO, 2001c). Coconut, an extremely hardy crop, provides food, drink and various kinds of useful materials to local populations. The development of the coconut sector is subsidized because coconut oil is a top vegetable oil export, destined to outstrip even soy in world production (ibid.).

Photo 9. Fulani camp in a Balanites aegyptiaca agroforestry parkland in the Sahel region of Burkina Faso (© Faiduti/FAO)

Foliage and fodder

Pastoralists in tropical areas derive their livelihoods primarily from animal husbandry, which is dependant on herb and tree layer fodder and browse. Tree foliage becomes the essential source of livestock feed where grasses are scarce. In the temperate countries, trees growing in stumped hedges traditionally supply winter fodder reserves for goats (Bortoli, 1987). Tree species play a leading role in feeding livestock in the more arid parts of the world, such as the Sahel and Sudano-sahelian zones, where grassland resources do not provide enough good quality feed year round, so tree resources take up much of the slack. In Mali, goats are fed tree fodder 34 percent of the time. For sheep the figure is 87 percent (Dicko and Sangaré, 1981), cited in Cissé, 1985). This fodder is sold on the big urban markets to feed animals reared in the concessions (Box 12). In Sudano-sahelian bush savannah silvopastoral systems, the preferred species for tree fodder are: Pterocarpus lucens (supplying a good 50 percent of the tree fodder fed to herds in north-western Burkina Faso), most acacias (Acacia senegal, Acacia seyal, Acacia raddiana, Faidherbia albida), Balanites aegyptiaca, and Ziziphus mauritiana (Bernard et al., 1995; Bortoli, 1987; Cissé, 1985). Three-quarters of the 10 000 woody species that grow in Africa are thought to be used for aboveground pasture (FAO, 1992).

Fodder resources can, however, be overexploited. Where branches are broken off too fast and the bark is gnawed away (leaving wounds), parasites often flourish (Bortoli, 1987; Cissé, 1985). Over-grazing can jeopardize the natural regeneration of some tree species. One example is Cordeauxia edulis, the main dry season feed source for camels and goats in the central plains of Somalia, where the species is gradually disappearing (FAO, 1992). Such systems need to be rationally managed. In Asia, farmers are beginning to plant trees for fodder, among other uses. In western Nepal, trees bordering sloping fields cover 41-58 percent of the demand for fodder (Fonzen and Oberholzer, 1984). Making the resource more accessible obviates the need to drive the animals to and from forested areas.

Boles and barks

Most gums, resins and latexes are world trade items, in addition to their frequent use by farmers and herders. This is true for latex from rubberwood, produced in both forest plantations and agroforestry systems, and for the commercially and industrially valuable product, gum Arabic. Acacia senegal and Acacia seyal are grown in the Sahel in agroforestry systems called "gum orchards" or in forest fallow tree systems. The world output of gum Arabic topped 60 000 t in the 1960s, dropping to 33 800 t in 1994 (Spore, 1991; Nour and Osman, 1997), and produced an average rate of 260g/tree/yr (Coppen, 1995). Gum arabic exports brought in nearly US$ 100 million in 1993 to Sudan, the top world producer (Danthu, 1994). No synthetic substitute has replaced gum Arabic, an inestimably valuable component of more than one industry -- further proof that non-wood, non-forest products can generate foreign currency within organized production systems.

Table 3: Selected permanent crop sectors: summary (1996 data)




Oil palm


Area* (millions ha)


Arabica: 6,8 Robusta: 4,3



Output (millions of tonnes)

2,5 (trade cocoa)

Arabica: 3,8 Robusta: 1,7

16,1(palm oil)

copra: 5,3
oil: 3,3

Geographical distribution

África: 60% Asia:25% America: 15 %

Africa: 18 % Asia: 18 % America: 64 %

Malaysia : 52% Indonesia : 28% Other : 64%

Asia : 80% (Philippines,India,

Production system

Mostly small planters

80 % smallholder farms

Africa: big plantations mainly Asia: also village plantations


Major technical constraints

Quality Replanting Diseases and pests

Quality Diseases and pests

Production potential for specific varieties Diseases and pests

Technical systems
Associated crops

Exports (main countries)

Côte d'Ivoire Ghana Indonesia

Brazil Colombia Indonesia

Malaysia Indonesia Papua New Guinea

Malaysia (oil)

Imports (main countries)



European Union China

 European Union 

Source: Follin, 1999
* All-inclusive


The bark of Prunus africanum yields an extract used in powdered form in traditional medicine in Cameroon. Though 3 500 t of bark are harvested every year, this is a vanishing species (Spore, 2000). Irvingia gabonensis and shea tree barks are exploited locally for their medicinal properties, and Grewia tenax bark (of which an estimated 900 t/yr is produced in Sudan), is used to make toothbrushes (Ayuk et al., 1999; Boffa et al, 1996; Ezeldeen and Osman, 1998; Ladipo et al., 1996). Tree bark may have wider commercial uses, for instance cork from cork oak (Quercus suber), which is grown especially in dehesas-typical agrosilvopastoral systems still common in southern Europe (Pointereau and Bazile, 1995).

Photo 10. Pollarded tree in Puy-de-Dôme, France. (© Bellefontaine/Cirad)


Essential oils, honey and other apiculture products are also derived from Trees outside forests. These products are not only of interest to the food, pharmaceutical and cosmetic industries, they constitute a lucrative sideline for many small farmers. Apiculture is popular in rural Mozambique, where acacia and miombo (Brachystegia) are the most common honeys. Some 20 000 traditional apiculturists produce an average 360 000 kg/yr of honey and 60 0000 kg/yr of wax. Modern apiculturists produce an estimated 20 000 kg/yr of honey, and 8000 kg of wax. The price of honey went from US$ 3.60 in 1994 to US$ 5.60 in 1999. (Mange and Nakala, 1999). Ethiopia follows China, Mexico and Turkey as the world's fourth wax producer (averaging 3 000t/yr), and is fifth in order of exports, exporting an average 270 t/yr in 1984-94 (Deffar, 1998).

Photo 11. Bicycle transport of cailcédrat tree fodder to feed home-reared sheep in Bamako, Mali. (© Bertrand/Cirad).


Beverages made from sap are popular, such as the familiar palm wine, made from species such as Borassus aethiopum, Hyphaene coraiacea and Phoenix reclinata. Palm wine production in Mozambique, with daily production figures as high as 20 l/day in the Matutuine region, is a lucrative, year-round activity for households living along the main roads (Mange and Nakala, 1999). In the Bassila region of Benin, palm wine-making and the related distilled product is the only tree-linked enterprise which can entirely cover a person's subsistence costs (Boffa, 2000a).

Box 12:

Trees outside forests as a source of livestock feed

Bicycles teetering under bundles of leaves weighing over 70 kg and carts stacked full of tree fodder are a common big city sight in some developing countries. A survey done in Bamako, Mali, showed that home-reared sheep were fed an average daily tree fodder ration of 1.8 kg of Pterocarpus erinaceus and Khaya senegalensis leaves (Anderson et al., 1994). From 1989-1990, over 1400 tonnes of fresh Pterocarpus erinaceus leaves were sold in Bamako. Gliricidia sepium leaves in Sri Lanka are among the preferred fodder transported for livestock feed. Their high nitrogen and/or energy contents make fodder legume pods and other tree fruits a crucial feed source. Acorns are fed to pigs in temperate and Mediterranean countries. In hot temperate regions, mulberry trees (Morus alba) are increasingly planted to feed ruminants, and not just for the silkworm industry. The fodder quality and digestibility of mulberry leaves are remarkably high, suggesting a very promising future for mulberry on both the Eurasian continent and in Latin America (Sanchez, 1999).

The income from Trees outside forests represents a considerable budgetary item for countries and a crucial one for rural people. If we had solid, reliable, economic data on the value of tree products from non-forest areas, their value would be enhanced, favouring their inclusion in national and international statistical databases.

A key environmental resource

An African adage has it that "Earth is not a legacy we inherit from our parents, but rather a loan from our children". It took two million years to arrive at the one billion men and women alive on the planet by the year 1800. By the year 2025, world population is projected to approach nine billion, of whom over seven billion in the developing countries. One billion people live in poverty (World Bank, 1995), and more than 800 million never get enough to eat (FAO, 1996a). The challenge is clearly to ensure that natural resource conservation and sustainability efforts are sufficient to reduce poverty and ensure the present and future inhabitants of town and countryside sufficient livelihood to guarantee food security. Trees outside forests can play a leading role in meeting resource conservation and management needs in both rural and urban areas Urban forestry is already crucial to environmental quality, and will increasingly be so in future, procuring the unequivocal ecological benefits of bettering the climate, limiting and channelling urban population growth, recycling waste waters, abating noise, and attenuating atmospheric and noise pollution (Greye and Deneke, 1978, cited in El-Lakany et al., 1999.

Box 13:

Gum arabic: a valuable product of Trees outside forests

Gum Arabic is a slightly acidic, complex, polysaccharide. It is highly water-soluble (its principal property), producing low viscosity solutions. This makes it a good emulsifier and stabilizer. Its three uses are nutritional, pharmaceutical and technological. In the industrialized countries it is used mainly in confectionery (60 percent of consumption) but also as a gel in preserves, and as a stabilizer in fizzy drinks and alcoholic beverages. Nomadic populations in Mauritania make N'dadzalla from it, which is the grilled gum, pounded and mixed with butter and sugar. It is used as a panacea in traditional medicine to treat migraine, fractures and skin eruptions. The pharmaceutical and cosmetics industries find it a valuable emulsifier and anti-precipitant. The gum is used in the artisanal sector to prepare glues, dyes and pommades. Printing, lithography, ceramics and selected inks all use gum Arabic as a base (Coppen, 1995; Giffard, 1975; Seif el Din and Zarroug, 1996).

For soil and water

The rate of soil degradation has now largely outstripped soil regeneration. This situation cries out for agricultural systems that respect the environment, nurture biological diversity, and maintain soil fertility. Trees outside forests are well-placed to meet this challenge effectively. In dense or thin stands, line plantings, singly or in hedgerows, trees preserve the organic matter contained in the soil (Roose, 1994) and boost its fertility. This is universally acknowledged, as is the role of trees in halting the advance of the desert, checking wind and water erosion, facilitating the percolation of rainwater, and enhancing agricultural production in the long term (Box 14).

Box 14:

Some environmental contributions of trees outside forested areas

In countries such as Egypt, Iraq and Libya, windbreaks have a substantially positive impact on production yields (FAO, 1986). Similarly, the 800 odd km of windbreaks planted in Mauritania have helped to fix dunes, hold back the advance of the desert, and combat drought (Ben Salem, 1991). Oases in Iraq intercrop a top story of palms, an understory of fruit trees and a ground crop (ibid.), a proven technique for checking wind erosion. Farmers in the mountainous areas of Iran leave 20 to 100 trees/ha standing on farmland to ensure soil and crop protection. For the same reasons, Afghan farmers grow mulberry trees, poplars, and eucalypts and fruit trees around their plots and along irrigation canals (FAO, 1993b). In arid African regions, single trees such as Faidherbia albida preserve soil fertility, protect the grass, and provide shade and shelter for people and animals.

In much of the world, pioneer encroachment upon the forest is a factor in natural resource degradation, so it is essential to conserve sufficient tree systems in all their various forms and layouts. Line-plantings are a source of great biological richness for ecological preservation, bio conservation, water purification, and storm protection. Trees growing outside forests in line-plantings, clumps or woodlots have a special role (Box 15) in conservation-oriented water, biomass and soil fertility management. Where properly established, tree plantings tend to replace more mechanical approaches to soil and water protection, conservation and restoration.

Box 15:

Soil protection and water conservation

The biological options for soil and water protection and conservation consist in the establishment of ground cover systems which recycle organic matter and help to disperse runoff energy. Where possible, micro dams are built on sloping lands, consisting of lines of stones, perhaps in association with grassy strips on which trees or shrubs are planted as living fences, in an arrangement designed to manage water, biomass and mineral nutrients (Bellefontaine et al., 1999). This kind of erosion control limits the need for tillage and provides a permanent cover of trees or leaf litter (Roose, 1999).

Trees outside forests, regenerating spontaneously and/or planted to maintain or extend tree cover, are of great benefit in watershed management, reducing soil degradation and controlling desertification. The rivers and streams of mountainous zones and their ecosystems are protected by streamside trees and those growing on farmland. The 1992 UNCED stressed that mountains are a major reservoir of water, energy and biological diversity, and that mountain environments are essential to the survival of world ecosystems.

Photo12. Rill erosion and the role of Trees outside forests in Togo. (© Sarlin/Cirad)

For biological diversity

No country can afford to ignore its phytogenetic resource base and at the same time expect to sustainably increase food supplies and address the issue of the environment, including climate change. Generations of farmers have given local communities an important role in the conservation and enhancement of these now seriously endangered resources (Leipzig Declaration, 1996). In the Sahel, the greatest threat to the maintenance and sustainable development of genetic resources is posed by the overexploitation of wood resources. The risk that tree species or populations may vanish is aggravated by recurrent bouts of drought. Species vary in their ability to withstand these attacks. Chad reports substantial losses of its stands of Acacia senegal, Anogeissus leiocarpus and Dalbergia melanoxylon. An estimated 100 000 ha of savannah are lost every year in Cameroon and Senegal. Species such as Acacia nilotica, Pterocarpus lucens, Sclerocarya birrea, Prosopis africana, Lannea microcarpa and Dalbergia melanoxylon are extremely sensitive to the impact of climate (FAO, 2001c).

There are two strategies for protecting these assets (Secretariat of the Convention on Biological Diversity, 2000). One is ex situ conservation in botanical gardens, arboretums, and conservation stands. In this context, genetic improvement and breeding programmes in the Sahel are already holding out serious promise for the future of Anacardium occidental and Faidherbia albida (Leipzig Declaration, 1996). The other strategy is in situ conservation, where farmers draw upon their knowledge of the interactions between the environment, genetic resources and their own management practices to protect biological diversity. Home gardens in many countries offer refuges for certain rare plant and tree species contributing to the biological spectrum (Box 16). This is also true of agroforests, with their high densities and great range of woody and non-woody species, which render environmental services comparable to those of the forest.

Box 16:

Home gardens and biological diversity

The traditional farming systems known as home gardens are vital to populations. A study in Thailand counted 230 plant species in 60 home gardens, including 29 wild species. Each garden had from 15-60 different species, including at least ten undomesticated species (Bunning and Hill, 1996). A great many tree, shrub and other plant species thrive in Pacific island home gardens. Musa, Pandanus and Ficus tinctoria, papaya, citrus trees, avocado, guava, Annona, Syzygium and Terminalia spp., Spondias dulcis and Pometia pinnata are all grown on the atoll of Kiribati, for example. This impressive diversity is amplified by the recourse to different varieties of the same species. Studies in the Solomon Islands have established that the nutritional status of households who have home gardens is better than those who do not, the latter being deficient in Vitamins A , C, and iron (FAO, 1995b).

Concerning the biodiversity of wildlife, areas of open tree cover support a more substantial and diversified biomass than forests. Serengeti in Tanzania is the best-known example of this: the park has the most impressively large herds of antelope in the world. Tree savannah furnishes shade, protection, browse and branches where animals can shelter, rest, or make their homes.

Hedgerows, windbreaks and woodlots on farmland also constitute refuges for wild plants and animals, forming islands of biodiversity and biological corridors. This function is very familiar to both hunters and farmers, who favour the conservation of hedgerows and woodlots. Farmers may harbour reservations about the resultant increase in bird and rodent pest attacks on their crops, but they also welcome the presence of pollinating insects like bees, insect-eating birds and animals useful for biological pest control. Often woody species (some rare or uncommon), grow and thrive at the foot of tree rows, their seeds having been distributed there by animals9 , in a further contribution to biodiversity. The existence of many animal species has been safeguarded by the planting, maintenance or restoration of bocage hedges. Trees lining rivers and streams are a source of great biological richness, providing spawning-beds for fish and shellfish, even as their shade acts to limit the development of aquatic flora, thus reducing eutrophication. These riparian woods also function as biological corridors for terrestrial wildlife. In the management of non-forest trees on farmland, the final goal is sustainable biodiversity in which a balance is struck between the beneficial impacts and the control (if not the elimination), of harmful ones.

Photo 13. Mountain landscape in south-western China. (© Hofer/FAO)

Concerning climate

Trees act as both reservoirs and potential sources of carbon. The role of tropical forest ecosystems in carbon storage and release is beginning to be known in the global context of the biosphere, in the regulation of atmospheric carbon, and in the reduction of greenhouse gases. The quantification of carbon sources and sinks and of wastes due to human activities is currently a major concern of the scientific community (Alexandre et al., 1999). Changes in land use, especially slash-and-burn practices and the resultant deforestation of tropical forest, are now responsible for some 20 percent of CO2 emissions (FAO, 2001a). According to the Intergovernmental Panel on Climate Change (IPCC), carbon fixation from reduced deforestation, forest regeneration, and intensified planting and agroforestry practices would amount to the equivalent of 12-15 percent of CO2 emissions from fossil fuels from 1995-2050 (FAO, 2001a).

It became clear during the international negotiations on global climate change leading up to the Kyoto Protocol that carbon could become a new "product" needing to be monitored, quantified and managed in new ways, compared to past treatment of the issue, and that the element will provide a new rationale for activities affecting climate change. Decisive changes must be made in the energy, transport and industrial sectors, as in agriculture and forestry. The impact of Trees outside forests on reducing deforestation, stabilizing soils and ecosystems and sequestering carbon will become increasingly meaningful.

Photo 14. Some islands and corridors of biodiversity maintained between forest (background at right) and field. The Belgian Ardennes. (© Bellefontaine/Cirad)

Selected forest management practices can slow the accumulation of atmospheric carbon. One item on the agenda of the 1997 Eleventh World Forestry Congress in Antalya, Turkey, was the expansion of carbon sinks by "the establishment of plantations on non-forested land, (...), the increase of forest cover on farmland or pasture through agroforestry systems" (Brown, 1997). Unruh et al (1993) estimated the amount of stored carbon in aboveground and underground biomass in 21 different agroforestry systems in subsahelian regions, concluding that the environmental role of agroforestry in terms of retaining organic matter in the soil and reducing deforestation (and thereby reducing CO2 emissions) is more important than its straightforward effect of carbon sequestration. Planting trees in non-forest areas as part of integrated land management efforts could help maintain stored carbon at acceptable levels. Much of the thinking on how Trees outside forests relate to climate regulation is still at the research stage. Resources should accordingly be mobilized to assess the importance of Trees outside forests within the carbon cycle (Alexandre et al., 1999) -- they have already proven rather effective in improving microclimates (Box 17).

Box 17:

Tree-planting to better the urban climate

In the Yangtse Valley in Nanking, China, an industrial city of some 1.5 million people, 34 million trees were planted from 1949 to 1981 - roughly 23 trees/person. The point of this urban and peri-urban tree-planting effort was to lower the ambient summer temperature, regulate the climate and purify the air, while at the same time beautifying the urban landscape. Local summertime temperatures dropped from 32,2o C to 29,4o C during this 32-year period, a reduction attributable to the cooling effect of the trees, which were planted along roads, in triple rows beside railroad tracks, on reforested hillsides and as windbreaks (Carter, 1995).

Consideration of the beneficial impact of Trees outside forests, particularly in terms of development issues such as enhanced food security, poverty reduction and ecosystem conservation has highlighted the critical need for hard and fast facts and figures to reliably underpin promotion and support policies for Trees outside forests. These data can also help to carefully monitor the changing patterns and dynamics of this valuable but still largely underestimated (and underrated) resource.

3 There is no one definition for such trees, which may be singled out for shape, age, species, or the local cultural values.

4 Designation of bamboo as a forest or non-forest resource depends on the country.

5 By masking we mean species or types of value not included in the national economic accounts and not known to the research and policy sectors (Guijt and Hinchcliffe, 1998).

6 As of 1999 the FAO definition of non-wood forest products (NWFP) refers explicitly to Trees outside forests: "non-wood forest products consist of goods of biological origin other than wood, derived from forests, other wooded lands, and trees outside forests" (Unasylva, 1999).

7 In 1995, one US$ was worth about 26 koruny.

8 In 1996. One US$ was worth about 511 CFA francs.

9 The distribution by animals - wildlife, livestocks, birds, etc.-- of fruit and/or seeds.

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