An e-publication by the World Agroforestry Centre
AN INTRODUCTION TO AGROFORESTRY
Cultivating trees and agricultural crops in intimate combination with one another is an ancient practice that farmers have used throughout the world. Tracing the history of agroforestry, King (1987) states that in Europe, until the Middle Ages, it was the general custom to clear-fell degraded forest, burn the slash, cultivate food crops for varying periods on the cleared area, and plant or sow trees before, along with, or after sowing agricultural crops. This "farming system" is no longer popular in Europe, but was widely practiced in Finland up to the end of the last century, and was being practiced in a few areas in Germany as late as the 1920s.
In tropical America many societies have simulated forest conditions to obtain the beneficial effects of the forest ecosystem. For example, in Central America, it has been a traditional practice for a long time for farmers to plant an average of two dozen species of plants on plots no larger than one-tenth of a hectare. A farmer would plant coconut or papaya with a lower layer of bananas or citrus, a shrub layer of coffee or cacao, annuals of different stature such as maize, and finally a spreading ground cover such as squash. Such an intimate mixture of various plants, each with a different structure, imitated the layered configuration of mixed tropical forests (Wilken, 1977).
In Asia, the Hanunóo of the Philippines practiced a complex and somewhat sophisticated type of "shifting" cultivation. In clearing the forest for agricultural use, they deliberately spared certain trees which, by the end of the rice-growing season, provided a partial canopy of new foliage to prevent excessive exposure of the soil to the sun. Trees were an indispensable part of the Hanunoo farming system and were either planted or preserved from the original forest to provide food, medicines, construction wood, and cosmetics (Conklin, 1957). Similar farming systems have also been common in many other parts of the humid lowland tropics of Asia.
The situation was little different in Africa. In southern Nigeria, yams, maize, pumpkins, and beans were typically grown together under a cover of scattered trees (Forde, 1937). The Yoruba of western Nigeria, who have long practiced an intensive system of mixing herbaceous, shrub, and tree crops, claim that the system is a means of conserving human energy by making full use of the limited space won from the dense forest. The Yoruba also claim that this system is an inexpensive means of maintaining the soil's fertility, as well as combating erosion and nutrient leaching (Ojo, 1966).
There are innumerable examples of traditional land-use practices involving combined production of trees and agricultural species on the same piece of land in many parts of the world. These are some examples of what is now known as agroforestry. Trees were an integral part of these farming systems; they were deliberately retained on farmlands to support agriculture. The ultimate objective of these practices was not tree production but food production.
By the end of the nineteenth century, however, establishing forest or agricultural plantations had become an important objective for practicing agroforestry. In the beginning, the change of emphasis was not deliberate. At an outpost of the British Empire in 1806, U.Pan Hle, a Karen in the Tonze forests of Thararrawaddy Division in Myanmar (Burma), established a plantation of teak (Tectona grandis) by using a method he called "taungya," and presented it to Sir Dietrich Brandis, the Governor. Brandis is reported to have said, "this, if the people can ever be brought to do it, is likely to become the most efficient way of planting teak" (Blanford, 1958). From this beginning, the practice became increasingly widespread. It was introduced into South Africa as early as 1887 (Hailey, 1957) and was taken, from what was then Burma, to the Chittagong and Bengal areas in colonial India in 1890 (Raghavan, 1960). The ruling philosophy of the taungya system was to establish forest plantations whenever possible using available unemployed or landless laborers. In return for performing forestry tasks, the laborers would be allowed to cultivate the land between the rows of tree seedlings to grow agricultural produce. This is a simplification of a system whose details varied depending on the country and locality (see Chapter 6 for details of the taungya system).
As a result of foresters' preoccupations with the forests and the forest estate, the main objective of the research undertaken by them on such mixed systems was to ensure that:
In short, the research conducted was undertaken for forestry by foresters. It appears the foresters conducting the research never envisioned the system as being capable of making a significant contribution to agricultural development, or its potential as a land-management system (King, 1987).
Many factors and developments in the 1970s contributed to the general acceptance of agroforestry as a system of land management that is applicable to both farm and forest. These factors included:
At the beginning of the 1970s, serious doubts were expressed about the relevance of current development policies and approaches. In particular, there was concern that the basic needs of the poorest, especially the rural poor, were neither being considered nor adequately addressed. Robert McNamara, the President of the World Bank at that time, confronted these concerns quite clearly (McNamara, 1973):
Against this backdrop of concern for the rural poor, the World Bank actively considered the possibility of supporting nationally oriented forestry programs. As a result, it formulated a Forestry Sector Policy paper in 1978, which has been used as the basis for much of its lending in the forestry sub-sector in the 1980s1. Indeed, its social forestry program, which has been expanded considerably since the 1980s, not only contains many elements of agroforestry but is reportedly designed to assist the peasant and the ordinary farmer by increasing food production and conserving the environment as much as it helps the traditional forest services to produce and process wood (Spears, 1987).
It was around the same time that, with the appointment in 1974 of a new Assistant Director-General responsible for forestry, the FAO made a serious assessment of the forestry projects which it was helping to implement in developing countries, as well as the policies which it had advised the Third World to follow. After assessing the program it became clear that although there was notable success, there were also areas of failure. As Westoby (1989) would later express it:
FAO redirected its focus and assistance in the direction of the rural poor. Its new policies, while not abandoning the traditional areas of forestry development, emphasized the importance of forestry for rural development (FAO, 1976). It also focused on the benefits that could accrue to both the farmer and the nation if greater attention were paid to the beneficial effects of trees and forests on food and agricultural production, and advised land managers in the tropics to incorporate both agriculture and forestry into their farming system, and "eschew the false dichotomy between agriculture and forestry" (King, 1979).
To these two strands of forest policy reforms, which evolved independently, one in an international funding agency and the other in a specialized agency of the United Nations, were added the simultaneous efforts of a large number of tropical land-use experts and institutions. Faced with the problems of deforestation and environmental degradation, these individuals and institutions intensified their search for appropriate land-use approaches that would be socially acceptable, ensure the sustainability of the production base, and meet the need for production of multiple outputs. Efforts to design major programs which would allow local communities to benefit directly from forests paved the way for new forestry concepts, such as social forestry, which were implemented in many countries.
Several developments in the area of agricultural research and development during the 1960s and 1970s were also instrumental in initiating organized efforts in agroforestry. Under the auspices of the Consultative Group on International Agricultural Research (CGIAR), several International Agricultural Research Centers (lARCs) were established in different parts of the world to undertake research with the objective of enhancing the productivity of major agricultural crops (or animals) of the tropics. The development of high-yielding varieties of cereals and related technologies through the joint efforts of some of these centers and the relevant national programs paved the way for what became known as the Green Revolution (Borlaug and Dowswell, 1988). However, it was soon realized that many of the green revolution technologies that placed a heavy demand on increased use of fertilizers and other costly inputs were beyond the reach of a large number of resource-poor farmers in the developing countries. Most of the IARCs and the national programs were focusing on individual crops such as rice, wheat, maize, and potato, and production technologies for monocultural or sole-crop production systems of these crops. However, the farmers, especially the poorer farmers, often cultivated their crops in mixed stands of more than one crop, and sometimes crops and trees; in such circumstances the production technologies developed for individual crops would seldom be applicable. These shortcomings were recognized widely by a large number of policy makers.
As a consequence, there was renewed and heightened interest in the concepts of intercropping and integrated farming systems. It was being demonstrated, for example, that intercropping may have several advantages over sole cropping.2 Preliminary results from research in different parts of the world had indicated that in intercropping systems more effective use was made of the natural resources of sunlight, land, and water. The research also indicated that intercropping systems might have beneficial effects on pest and disease problems; that there were advantages in growing legumes and nonlegumes in mixture; and that, as a result of all this, higher yields could be obtained per unit area even when multi-cropping systems were compared to sole cropping systems (Papendick et aI., 1976).
It became obvious that although a great deal of experimentation was being carried out in the general field of intercropping, there were many gaps in our knowledge. In particular, it was felt that there was a need for a more scientific approach to intercropping research, and it was suggested that greater efforts were needed with respect to crop physiology, agronomy, yield stability, biological nitrogen fixation, and plant protection (Nair, 1979). Concurrently, the International Institute of Tropical Agriculture (IITA), an IARC in Ibadan, Nigeria, extended its work to include integration of trees and shrubs with crop production (Kang et al., 1981). Other research organizations had also initiated serious work on, for example, the integration of animals with plantation tree crops such as rubber, and the intercropping of coconuts (Nair, 1983).
Building upon the success of these scientific studies, agricultural scientists began investigating the feasibility of intercropping in plantation and other tree crop stands as well as studying the role of trees and shrubs in maintaining soil productivity and controlling soil erosion. Livestock management experts also began to recognize the importance of indigenous tree and shrub browse in mixed farming and pastoral production systems.
Environmental concerns became very conspicuous at the same time as these changes and developments were happening in the land-use scenarios of tropical forestry and agriculture. Deforestation of the world's tropical region, which attained the status of a "hot topic" on the agenda of almost all environment-related discussions at all levels during the 1980s, was a major environmental issue even during the 1970s. Definitions and estimates of the rates of deforestation vary. For example, the World Bank, which defines deforestation as the disturbance, conversion, or wasteful destruction of forest lands, has assembled statistics on the extent and progression of deforestation in the tropics during the past two decades, and estimated the current rates at about 12 million hectares per year (World Bank, 1991; Sharma, 1992). The World Bank's data on average rates of deforestation and reforestation in the world during the 1980s is given in Figure 1. FAO, on the other hand, based on its preliminary estimates from the 1990 assessment, reports that the actual rate of deforestation during the 1980s was about 50% higher, 17.1 million hectares annually (Matthews and Tunstall, 1991). As pointed out in a study by the World Resources Institute, one of the main reasons for these differences is that many of the assumptions on which estimates of the extent of tropical deforestation are made have proven false, and very little effort is being made to update the information systematically (World Resources Institute, 1990). In spite of these differences in its estimates, there is no divergence of opinion on the consequences of deforestation: it is widely agreed that deforestation causes a decline in the productive capacity of soils, accelerated erosion, siltation of dams and reservoirs, destruction of wildlife habitats, and loss of plant genetic diversity (World Bank, 1991). It is also generally agreed that the main causes of this deforestation are population resettlement schemes, forest clearance for large-scale agriculture, forestry enterprises and animal production, and, in particular, shifting cultivation. A 1982 FAO estimate showed that shifting cultivation was responsible for almost 70% of the deforestation in tropical Africa, and that forest fallows resulting from shifting cultivation occupied an area equivalent to 26.5 % of the remaining closed forest in Africa, 16 % in Latin America, and 22.7 % in tropical Asia (FAO, 1982). Faced with these challenges and maladies of deforestation, several studies and efforts were made to reduce the extent of deforestation and suggest alternative land-management strategies. Though the problem has, unfortunately, not been contained, several sound strategies have evolved, thanks to the efforts of large numbers of researchers from different disciplines. For example, ecologists produced convincing evidence of positive influence of forests and trees on the stability of ecosystems, leading to the call for measures to protect the remaining forests, introduce more woody perennials into managed land-use systems, and change farming attitudes. Studies carried out by anthropologists and social scientists on farmer attitudes to improved land-use systems showed the importance of mixed systems in traditional cultures and highlighted the need to build upon these practices when developing new approaches.
Although the initial assignment stressed the identification of research priorities in tropical forestry, Bene's team came to the conclusion that first priority should be given to combined production systems which would integrate forestry, agriculture, and/or animal husbandry in order to optimize tropical land use (Bene et al., 1977). In short, there was a shift in emphasis from forestry to broader land-use concepts which were perceived as having immediacy and long-term relevance.
How was the agroforestry research that was proposed by Bene and his team to be undertaken? Their report stated:
It was apparent that despite the growing awareness of the need for information, on which agroforestry systems might be effectively based, very little research was being undertaken. Furthermore, the research that was being conducted was haphazard and unplanned. The IDRC Project Report, therefore, recommended the establishment of an international organization, which would support, plan, and coordinate, on a world-wide basis, research combining the land-management systems of agriculture and forestry. This proposal was generally well received by international and bilateral agencies; subsequently, the International Council for Research in Agroforestry (ICRAF) was established in 1977. The ancient practice of agroforestry was institutionalized for the first time.
This congruence of people, concepts, and institutional change has provided the material and the basis for the development of agroforestry since then. Although many individuals and institutions have made valuable contributions to the understanding and development of the concept of agroforestry since the 1970s, ICRAF - renamed in 1991 as The International Centre for Research in Agroforestry - has played the leading role in collecting information, conducting research, disseminating research results, pioneering new approaches and systems, and in general, through the presentation of hard facts, attempting to reduce the doubts still held by a few skeptics.
Today, agroforestry is taught as a part of forestry- and agriculture-degree courses in many universities in both the developing and industrialized world. Today, agroforestry, instead of being merely the handmaiden of forestry, is being used more as an agricultural system, particularly for small-scale farmers. Today, the potential of agroforestry for soil improvement and conservation is generally accepted. Indeed, agroforestry is fast becoming recognized as a land-use system which is capable of yielding both wood and food while at the same time conserving and rehabilitating ecosystems.
1 The World Bank's Forestry Policy, which was further revised in 1991 gives even more emphasis to agroforestry and "trees outside the forest" (World Bank, 1991).
2 Some of these common land-use terms are explained in the glossary at the end of the book.