Trees outside forests: Contributing towards sustainable development

Syaka Sadio and Patricia Negreros-Castillo 1

"Today as yesterday, the only solution is to plant trees"
Johan van der Linde, 1962


The impacts of the world population growth, urbanization and consumption patterns are manifest in the widespread degradation of land and natural resources and also in ever-increasing poverty. Trees can help solve these problems because of their ability to restore degraded ecosystems, produce food and medicine, and provide environmental and economic benefits. Trees outside forests (TOFs) will have an increasing role in reducing degradation and poverty and will assist in sustainable development.

Currently TOFs are not benefiting many people because:

1. Introduction

Agricultural and urban expansion has been occurring at the expense of native ecosystems and the landscape made up of forests, woodlands, croplands, and grasslands.. The cumulative effects of this expansion have produced serious global environmental and social problems, including loss of biodiversity and extreme poverty of people living in the more vulnerable areas (FAO, 2001a; Van der Linde, 1962).

One solution to these problems is to plant and manage trees. Trees provide a range of benefits, including the potential to restore degraded ecosystems, provide wood, other on-woody products such as food and medicines, and to render environmental and socio-economic services. The importance of trees in addressing these problems is clearly demonstrated in traditional tree-based agricultural farming and land use systems, such as shifting cultivation in the humid tropics, fallow systems and grazing in the semi-arid savannah areas. Research during the 1970s and 1980s has shown the important role of trees in structuring landscapes and improving land productivity (Mando, 1997; Manu et al., 1995; Sadio, 1990; Young ?).

However, trees outside forests received little attention from decision and policy makers until the Kotka meeting in 1993 (FAO, 2000), which adopted the concept.2 The meeting defined trees outside forests as trees found on non-forest or wooded lands such as those occurring in agricultural or urban areas or along roadways. Their importance has become more apparent since that meeting and the ideas have been abandoned that they only make sense for small-scale farmers or have just ornamental or scenic functions in urban centers.

This paper presents key issues related to TOF, including their roles and uses and how they meet people's needs.

2. Multiple roles and benefits of TOF

Trees fulfil many important roles and produce a range of benefits to people and the environment..

Production role and benefits

Food and other essential goods

TOF have been called "trees that nourish". This is particularly true for many poor and landless people who obtain essential products from them (Manu and Halavatau, 1995). Many trees species found in African and Asian agro-forestry systems (eg. Borassus aethiopum, Balanites aegyptiaca, Ziziphus mauritiana, etc.) are planted for their ability of produce large quantities of food and other non-wood forest products (Box 1).

BOX 1: Trees for food

Borassus aethiopum:

i) the kernel and mesocarp of the fruit are eaten;
ii) the jelly-like, immature fruit is delicious, and a decoction of the roots makes a cooling drink for infants;
iii) the sprouts are prepared as a vegetable;
iv) the sap is used to make wine; and
v) the leaves are suitable for weaving roofs and fences.

Vitellaria paradoxa:

i) the pulp is eaten raw, and
ii) the kernel supplies oil used in cooking, cosmetics, candles, and even for waterproofing the walls of farmers' homes.

For example, in Burkina Faso the nut is commonly used and plantings there yield an average production of 48-65 kg/ha/yr of dry fruits. Some 40000-75000 tons are exported to Europe and 10000-15000 tons to Japan, where it is used incosmetics, pharmaceuticals and in baking.

Source: FAOb, 2001

Sustainability of agricultural production

One of the most universally recognized roles of trees in agricultural systems is as a way to replenish fertility (Chivaura-Mususa et al 2000; Sánchez et al 1998). In many parts of the world, improved tree-based systems, e.g. shelterbelts, windbreaks, alley cropping, hedgerows, home gardens, tree cover crops (coffee, cacao, coconut, olive trees, orange, citrus, etc.), have been adopted to protect lands and improve agricultural crop production. For instance, in semi-arid and sub-humid countries integrated tree-crop-livestock management systems using agro-silvipasture, alley cropping, conservation agriculture3and using nitrogen fixing woody species, such as Acacia, Prosopisand Glyricidia species have restored soil fertility and physical properties, and decreased erosion and desertification (Huaxin, 2001, Liu 2001). Multi-storey tree-crop systems have been developed for desert and oasis areas of the Near East countries and are likely to both check wind erosion and improving food production (FAO, 1993).

Woodand woodfuel products

In developing countries 80% of harvested wood is used for energy and woodfuel is the most widely used source of fuel in rural and peri-urban areas.. For instance, in the Asia-Pacific area, trees outside forests supply over two-thirds of the energy demand, as firewood and charcoal, for two billion people. Woodfuel supplies 50% of energy used in Thailand, 75-85% used in Vietnam, Pakistan, Sri Lanka, the Philippines, Java and Indonesia, and 83% used in Kerala (FAOb, 2001; Jensen, 1995).

In Africa, Asia and Latin America many valuable trees species are also planted by local people for timber production and as means of saving for the future, a kind of piggybank (FAO, 2001b, Negreros-Castillo and Mize, 2002)

Fodder suppliers

Tropical pastoralists that derive their livelihoods primarily from animal husbandryare dependent on grasses, forbes, and fodder trees. In temperate countries, trees in coppiced hedges traditionally supplied winter fodder for goats. Trees play a major feed role in arid zones, such as the Near East and the Sahel and Sudano-sahelian zones In arid areas grassland do not provide adequate feed year round and tree fodder can take up much of the slack (Box 2).

Box 2: Trees outside forests as sources of livestock feed

A 1989-1990 survey in Bamako, Mali, found that home-reared sheep were fed 1.8 kg of Pterocarpus erinaceus and Khaya senegalensis leaves each day, and that over 1400 tonnes of fresh Pterocarpus erinaceus leaves were sold in Bamako each year????????.

In Sri Lanka, leaves of Gliricidia sepium are among the preferred fodders for livestock feed. Their high nitrogen and energy content make these legume pods and other tree fruits a crucial feed source.

Acorns are fed to pigs in temperate and Mediterranean countries (Anderson et al., 1994).

Recent case studies from Latin America have highlighted the important role that trees play in feed for livestock production (Sanchez et al, 1999). In the Soudano-Sahelian Africa, three-quarters of the 10,000 woody species that grow in silvipastoral systems are thought to be used as fodderand they supply up to 50% of livestock feed (FAO, 2001b).

Environmental services and socio-cultural values (externalities)

Trees outside forests improve air quality and microclimate, provide water protection, wildlife habitat, recreation and increased carbon sequestration and biodiversity. They are also imbued with symbolic cultural value being important parts of language, history, art, religion, medicine, politics, and so forth. They are sometimes called "trees of wonder" due to their longevity or their impressive size..

3. Challenges facing Trees Outside Forests

At national and international levels, the importance of TOF as a resource often is overlooked. Only limited initiatives existed prior to 1993, when the Kotka meeting analysed their role in the context of the world forest resources assessment. Since then, many case studies, conducted at national and regional levels, have identified serious challenges facing the successful promotion of trees outside forests as a tool for rural sustainable livelihoods and environment improvement.

a. Continuous population pressures on lands and forest resources

High population pressures on limited lands and forest resources have led to the breakdown of traditional tree-based systems practices that allow regeneration of vegetation cover. Systems such as shifting cultivation, and nomadic grazing in the semi-arid areas, that had become well proven by centuries of use, have often broken down leading toland and soil degradation, adverse environmental impacts and increased poverty.

One of the biggest challenges will be promoting TOF systems within the context of climate change. High population pressure on limited land resources may also hinder their acceptance

b. Improved National Forestry Programmes

For governmental decision makers and planners to include TOF in their national policies and tree planting programmes there needs to be relevant information that clearly demonstrates the benefits and important roles of trees in sustainable development.

An important challenge is how to give TOF more prominence as a route toward more sustainable livelihoods for the rural poor. A good solution would be to integrate TOFs into national agriculture and forestry development plans, byfocussing on the needs of local people to create their own woodlots, protect their environment and improve their livelihoods.

c. Limited incentives measures to promote TOF

Trees are commonly found in rural farms, but not at a level needed to achieve desired environmental services and economic benefits (Alvarez et al 2001). Many case studies (FAOb, 2001) pointed out that few farmers can afford to plant at the necessary scale and that investment is only encouraged when there are policy incentives and prospects of a worthwhile return on their investment

Legal and market barriers are amongst the biggest challenges undermining TOF promotion, particularly at the farm level. For instance, national forestry laws are frequently not particularly favourable to small on-farm tree planting and private investment in forestry, often due to land tenure systems and restrictions on forest product harvesting. Legal changes to land and tree tenure are often critical for TOF promotion, because they secure the stakeholders' benefits.

d. Wood, the environmentally friendly raw material

With increasing needs of poor people for fuelwood, wood consumption will increase at an alarming rate, beyond the potential of current forest resources.

A major challenge to forestry is convince people that using wood and woodfuel is environmentally friendly. Wood from well-managed trees is a low energy, sustainable alternative to steel, concrete, aluminium and plastic (RIRDC, 2000). TOF have great potential to provide these products and helpmeet their growing demand..

4. The way forward: Scaling up promotion of TOF

It is generally agreed that increasing agricultural productivity is central to growth and poverty alleviation in rural areas. It is also well understood that increased farm production often results in the destruction of forest cover, depletion of fertile soil, and severe land degradation.

The TOF concept has the potential for assisting with the goal of sustainable development. To be effective tree issues need addressing in a holistic, people-centered vision that focuses on the multiple functions of trees.

Building knowledge and capacities

The past two decades have witnessed the development of techniques to design landscape mosaics based on tree-crop integration and environmental protection. These techniques present large and small farmers in developing countries with a wide choice of tree species and management systems. However, results of many recent case studies, meetings and workshops (FAO, 2001b; FAO, 2002) have highlighted the need for further research to enhance their proper use in landscapes and to better achieve environmental and economic viability..

Two priority actions are:

Changing attitudes and visions

Foresters usually associate themselves with forests, agriculturist with crops, and livestock producers with domestic animals. TOF, being a cross-sector issue, raises the question "Who will take care of TOF?"

A combination of natural resource management approaches is probably required. However, foresters, who are the most familiar with trees and ecosystem functioning, need to play a more active role in TOF.. This shift is necessary to promote TOF and to promote integrated land-use systems, but not because the authors see a gloomy future for forestry. On the contrary, they see in TOF a great tool to help ensure a brighter future for sustainable forest resource management and the livelihoods of many people.

Bridging the gap between population needs and policymakers

Millions of vulnerable people living in rural and peri-urban areas rely heavily on forest resources for their livelihoods, but they lack an effective political and decision voice and rights. In this context, it is futile to attempt to protect forest resources without addressing their local needs and extending their rights.

To bridge the gaps between their needs and conservation needs, forest and tree resources must be managed for sustainable livelihoods with the objective of attaining a multi-functional landscape that yields a range of goods and services. We believe that a bold approach that gives stakeholders a voice and rights to decide what to do and what is necessary, should focus on assessing their needs and knowledge and determining the vulnerability of their production systems in their local farm context. This will require other simultaneous actions, such as multiple scale activities and careful consideration of how social and political changes influence success of different interventions and management practices.

Legal measures, policy, and market incentives

Farmers will engage in planting more trees when there are policy and market incentives to signal scarcity and channel investments.

Formal acknowledgement of rural peoples' user-rights over trees growing on farmland would provide a major incentive for the conservation of such trees. Tree management in farms makes good economic sense for some properties when all the benefits are taken into account in a `whole farm' evaluation approach. This would include indirect benefits of trees expressed in both environmental and monetary terms. A good example of environmental services to include is the additional carbon sequestration by new tree planting (World Bank 2002).

Gender differentiated management

Women are the first to be concerned with the selection and harvest of non-wood forest products (leaves, roots, fruits, etc.) and have better overall knowledge of their use, conservation, and processing. A study done in Java showed that 60% of a family's food comes from home gardens in which trees are prominent and that those gardens are mostly managed by women (FAO, 2001a). This important skill should be taken into consideration and seen as reason enough to enhance and strengthen the role of women in the management of TOF.

Fostering an international dialogue to advocate TOF issues

Awareness raising for TOF promotion will be of particular relevance particularly for low forest cover countries in order to increase forest cover and satisfy increasing needs for wood and non-wood forest products.

Three important international conventions -- Climate Change Convention, the Convention on Biological Diversity, and the Desertification Convention (Ruis, 2001) -- potentially have important roles to play in promoting TOF. They are in strategic positions to advocate for TOF because of their large audience and also because of the potential role that trees can play to achieve their ultimate goals.


On the basis of their biological characteristics and the wide range of resource types, TOF can be extremely useful for helping achieve sustainable rural development and to restore the planet's environmental health. These are two of the most important global goals and challenges we face today.

TOF is one of the most valuable tools available to help transform unhealthy cities into healthy ones and improve low productivity agricultural into high yielding and profitable agriculture.

Finally, if this new vision is embraced by many nations and expressed in the form of policies that effectively link TOF to all land-use systems, the accumulated effect of these changes will be reflected in a significant improvement in the global environment and in achieving sustainable rural development. A productive farm is the first step towards sustainable development for rural families. A healthy environment is important for all human societies and the beauty that integrated trees in the landscape provide is important for the human spirit.


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1 Agroforestry and Land Use Officer, Forest Resources Division, Forestry Department, FAO, Viale delle Terme di Caracalla, 00100 Rome, Italy. Syaka.Sadio@fao.org

2 : Trees Outside Forests are "Trees found on non-forest and non-wood lands", i.e. agricultural lands, urban and settlements areas, along the roads, home gardens, hedgerows, scattered trees in the landscape, pasture/rangelands and composed of different types of resources (FAO, 2000). The concept recognizes the uniqueness of the biological characteristics that trees have and allow them to full fill all their environmental, social, cultural and economic roles and benefits, including their wider integration for all land-use systems (rural and urban).

3 : The concept of "conservation agriculture" implies the following principles: i) no or less tillage to avoid mechanical soil disturbance; ii) direct seeding or planting of the crop; iii) maintenance of permanent soil cover with crop residues, cover crops and trees; and iv) judicious choice of cropping systems.