Overstory #105 - Complex Agroforests
Farmers have integrated trees in their farming systems for centuries. They did not wait for scientists to develop the concept of agroforestry, just like man did not wait for agronomists to invent and develop agriculture. Agroforestry is widely promoted as a solution for developing more sustainable land uses. But most policy makers, scientists and extension agents dealing with agroforestry programs rarely consider that most agroforestry systems have evolved from local farmers' practices. What farmers are actually doing indeed differs from one country to the other in the region. However, agroforestry is still mainly understood in terms of "development projects," and therefore is usually promoted from an outside point of view, with outside tree crops or mixed-cropping techniques. With few exceptions, projects do not explore either the local agroforestry knowledge base nor the local farmer-developed agroforestry practices.
How do traditional systems differ from modern systems?
Systems usually perceived as 'traditional' (or indigenous) are those systems that have been developed by farmers in response to perceived needs and existing opportunities, without the involvement of formal research and extension services.
Systems usually perceived as modern are those systems that have been developed by scientists and that are promoted by projects using techno-scientific arguments.
Both traditional and modern systems may co-exist at the same time. The main difference is that traditional systems are the result of long evolution and adaptation to local conditions, while long-term suitability of modern systems to local conditions is unproven.
A division can be made between two broad groups of agroforestry systems: simple agroforestry systems and complex agroforestry systems. Simple agroforestry systems are tree-crop associations and are easily recognisable once one has accepted that farmers are indeed agroforestry practitioners. Complex agroforestry systems are much more difficult to recognise: they are successional systems and, while early stages usually exhibit typical agroforestry features, their mature "forest" phase -- agroforest -- has often been confused with natural forests, even by agroforestry experts. Simple agroforestry systems are briefly presented below, followed by a focus on the lesser-known complex agroforestry systems.
Simple agroforestry systems
Simple agroforestry systems can be characterised as follows:
A mix of perennial and annual crops with:
- One tree species and one to a few annual crops, or short-cycle species; or
- Trees as main field components (e.g. coconut with maize or peanut); or
- Trees as borders such as teak (Tectona grandis), mahogany (Swietenia macrophylla) and rosewood (Dalbergia latifolia) in East and Central Java, and Maesopsis and Paraserianthes in West Java.
- Trees are also commonly associated with irrigated rice fields either on dikes or along roads, and are used in the agricultural system either for their products, for environmental services or for both. An example is coffee associated with Erythrina or Gliricidia trees. Reasons for planting Erythrina/Gliricidia are:
- to provide a manageable level of shade for coffee trees (through pruning),
- to provide firewood or fodder
- as a live pole for climbers (e.g. vanilla or pepper)
- to improve soil fertility through litter fall, fixing nitrogen from the air, old tree-root channel etc.
Complex agroforestry systems
Common observers often confuse multispecies complex agroforestry systems bordering obvious agricultural areas, especially on the forest margins, with a mix of "virgin" and "degraded" forest.
This kind of agroforestry combination that looks like forest, we call a complex agroforestry system. In its mature phase complex agroforestry is characterised by:
- A complex vegetation structure,
- A high number of components (trees as well as seedlings, shrubs, lianas, herbs), and
- An ecological functioning similar to that observed in natural forests (nutrient cycling, dissemination and regeneration processes, etc).
Two broad categories of complex agroforestry systems should be distinguished: tree-dominated homegardens and what we have called agroforest or complex agroforests.
Tree-dominated homegardens are always located near the house and are usually small (0.1 to 0.3 ha). These two characteristics allow homegardens to benefit from quite intensive care (manure, tree pruning, weeding, etc). Being easily recognisable because of their integration within household compounds, tree-homegardens are relatively well known and documented, and their importance is well acknowledged.
Agroforests are composed of a mosaic of small (1-2 hectares) individually-owned, individually managed units which make up forest massifs of various sizes. They are not located in household compounds, even though they often border villages, and they are rarely intensively managed. Agroforests are sometimes managed forests, evolved from progressive and integrated transformations of the original ecosystem through tree planting and natural vegetation management, such as the Benzoin agroforests in North Sumatra province. But most often agroforests in Indonesia evolved from shifting cultivation systems, and are true plantations established after total removal of the original vegetation through planting of desired tree species, and through natural enrichment. Agroforests are definitely part of the world of smallholder tree-crop plantation agriculture. Like coffee or cocoa smallholder plantations, agroforests are established and managed by rural households, mainly because of the medium to long-term sources of income they provide.
Examples from Indonesia
- In the hills and lowlands of Kalimantan and eastern Sumatra where the last tracks of mixed Dipterocarp forest are being logged and rapidly converted, smallholder jungle rubber agroforests cover an estimated area of 2.5 million hectares. In these systems rubber trees are associated with numerous wild and cultivated tree species, complementing either irrigated or dry rice cultivation.
- In the southwestern coast of Sumatra, an impressive model of agroforest based on Shorea javanica (damar) is exploited for its resin. It was developed by villagers more than a century ago and now covers some 50,000 hectares.
- Across Sumatra in the mid-1980's, a mosaic of other agroforest types was estimated to cover more than 1 million hectares in patches of a few hectares. It associates various fruit species as well as economic spice producing trees (cinnamon, clove and nutmeg) and timber species under a canopy of durian (Durio zibethinus) or kemiri (Aleurites moluccana) trees.
- In East Kalimantan impressive fruit forests have been developed (lembo) which seem to be among the richest systems in number of tree species.
Agroforests are definitely not anecdotal in terms of production, at regional nor national levels. They provide:
- 80% of the rubber latex consumed and exported by Indonesia (the world's second largest producer after Thailand);
- 95% of the various fruits marketed in the country;
- 75-80% of the Dipterocarp damar resins traded in and outside the country; and
- A significant portion of rattans, bamboo and firewood used in the country, and the bulk of medicinal plants and handicraft material.
Moreover, agroforests ensure the self-sufficiency of most rural households in complementary foods, fuelwood as well as light and heavy material.
Why should we grant special consideration to agroforests?
In spite of their relative success in the conditions in which they were conceived, indigenous agroforests are usually not transferable as such to other regions or other countries. Nor should they be considered as the pinnacle of agroforestry practice in the regions where they do exist.
Rather, they represent a very valuable source of inspiration and should be considered as models of utmost interest for the development of sustainable forms of agriculture and/or of forestry. They combine durable economic profitability and long-term conservation of both soil fertility and global biodiversity. Farmer-developed agroforests exhibit qualities that interest the present and future development of both agriculture and forestry, especially in areas where annual food crop cultivation depends on heavy applications of fertilisers or where only perennial crops are capable of sustained production.
For agricultural development
Agroforests provide a proof-tested original model of sustainable and profitable commercial agriculture suited to conditions prevailing in smallholder farms.
The development of commercial agriculture, especially perennial crops, is often planned and implemented as a total conversion of actual production systems to monocultures with high inputs of energy, capital and labour. Experimentation and domestication research on commercial tree crops are almost always conducted under standard conditions which are far from those commonly encountered on smallholder farms.
Local production systems in rural areas, including agroforests, are generally considered as devoted to subsistence production. Promotion of commercial agriculture on smallholder farms includes a technological "package" that entails a total reorganisation of farming systems. There is generally no attempt to develop an integrated process by taking advantage of the existing structures and practices. Agroforests, when they have been recognised, are generally considered by outsiders as mere kitchen gardens, i.e. no more than an anecdotal complement to open field cultivation for self consumption, and providing villagers with complementary foods and light materials like firewood.
Facts and recent studies on agroforests show the tremendous economic importance they have for local communities. Agroforests do provide complementary food and various material products; but, as in other tree-crop plantation systems, their main immediate/direct role for smallholders is to supply a regular flow of income. Agroforests are often the sole source of cash for households: in Sumatra, agroforests provide 50-80% of villages' total income through both products and activities linked to their collection, processing and marketing. Like most tree-crop plantations, agroforests are also part of a capitalization strategy: these long-lived plantations are created assets and they become part of a patrimony that will stay in the family and be transferred to children.
From Farmer Perspective
As a model for commercial agriculture, agroforests provide additional benefits to farmers:
As a "bank" that enables the diversification of income sources and rhythms. Income from agroforests usually covers both everyday expenses -- with regularly harvested products such as rubber latex, resin, cinnamon bark, and, at least partly, annual expenses -- with seasonal products such as fresh fruits, coffee, clove, nutmeg. Other commodities, such as timber, provide occasional, but important, sums of cash that often serve as savings for exceptional expenses.
Agroforests provide both security and flexibility through the diversification of commercial crops under a permanent structure. Diversity, though not allowing rapid accumulation of capital in the form of immediately realisable assets, constitutes an important insurance for farmers against risks of single crop failure or risks inherent to the unpredictable evolution of market prices.
Flexibility is an important quality for smallholders: in cases of falling prices of one commodity, the concerned species can simply be neglected in the garden for a while until its exploitation becomes profitable again. This process does not involve any disruption to the system itself In ecological terms, the agroforestry plot will be maintained intact and will still be productive, the concerned species will survive in the structure and will be ready for further exploitation, and new species can be introduced as well. In economic terms, there will still be something to harvest, or even new productions to try without reorganising the farming system. Another mark of flexibility is the shift in economic status that some species may encounter: species, present sometimes for decades in the agroforest, may suddenly acquire a new commercial value following market evolution. This has been the case in the 1980's in many places of Sumatra for fruits such as durian and langsat (Lansium domesticum), and more recently for timber.
Agroforests ensure the subsistence needs of farmers through its diversity of secondary products: agroforest acts as a common "kitchen garden" providing complementary foods (fruits, vegetable, spices), medicines and other products.
From shifting cultivator perspective
Agroforest systems provide a tested model for a successful transition from shifting cultivation to sustainable and profitable permanent agriculture.
We have discussed some of the direct benefits agroforests provide to smallholders' economies: diversification of income sources and rhythms, risk reduction and flexibility, diversity of secondary production, and creation of an inheritance. One other point has to be mentioned: establishment of agroforests and subsequent management operations require little investment, in terms of both labour and cash. Therefore, even though yields of the dominant species are not as high as in intensive monoculture plantations, agroforests provide a very good return to labour. This point is especially important as labour and cash resource, not land availability, represent the main constraint farmers' face in most shifting cultivation areas in the humid tropics.
No sophisticated techniques are needed. On the contrary, they are based directly upon shifting cultivators' traditional knowledge of their forest environment.
Agroforest establishment processes are directly linked to shifting cultivation. The planting in the swidden of trees, which is well known to local people and fully acknowledged to target economic value, will divert the whole destiny of the field, from a swidden/fallow cycle to an agroforest. This results in a permanent mosaic of the landscape, with areas permanently devoted to food crops and forest-like areas which are now efficiently protected, as they represent the major economic component of surrounding village communities.
In the sphere of forestry, agroforests provide a silvicultural model that integrates farmers, a diversified production of forest products, and the conservation of biodiversity.
Benefits of agroforest systems to the field of forestry can be listed as follows:
Simple techniques for managing complexity
Most agroforests are true plantations established, after total removal of the original vegetation, through planting selected species and through natural or directed enrichment. Agroforest establishment does not involve sophisticated techniques. Neither does agroforest maintenance, which involves techniques closer to gardening than to dominant forestry models for tree-crop plantation.
Alternative model for diversified timber production
Commercial timber production is considered as the exclusive domain of big private or State companies. Existing production from complex agroforestry systems is rarely mentioned and statistics are either not accurate or lacking. Nevertheless both the existing and potential resources offered by agroforest systems, and the timber management practices developed by agroforest farmers are worth investigating.
Agroforests as those encountered in Maninjau district, West Sumatra province, illustrate the potential of these systems as alternative models for sustainable timber production by smallholders. Under a canopy dominated by high durian trees, mixed with various forest species, commercial crops (cinnamon, coffee, and nutmeg) are grown, as well as various fruit trees, palms, bamboo, and medicinal plants. Timber production relies on the cultivation of selected timber species, on the management of naturally occurring forest species, and on the value of various fruit tree species.
Even though more research is needed, we can already underline the remarkable adaptation of agroforests to the integration of sustainable timber practices in their already diversified overall management. Agroforests are all characterised by an abundance of potential timber trees, a large supply of timber species seeds and seedlings, and the fact that the species involved are well known and managed by villagers for long.
Alternative model for the conservation of forest biodiversity outside protected areas
It is commonly acknowledged that the replacement of natural ecosystems with agricultural systems by man involves a drastic reduction in biodiversity. This is also the case with forest plantations, even though it is less commonly recognised. As far as species composition is concerned, an Eucalyptus plantation for instance, though it is often called a "forest" and succeeds in restoring a forest material, is definitely closer to a cassava field than to a natural forest.
Complex agroforestry systems, such as those encountered in Indonesia, have not only proven to be economically profitable, compatible with high population densities (up to 100-150 inhabitants/km2), and ecologically viable in the long term. They also are the only production system in tropical lands, which allows combining agricultural production with the conservation of a high degree of biological diversity.
Agroforests replace previous natural vegetation with a complex community of perennial species, which not only allows the direct conservation of numerous useful forest species, but also acts as shelter for hundreds of forest species not directly useful in our present state of knowledge.
In the present global context of degradation and destruction of tropical forest resources, and given the current trends of "dispossession" of traditional rural societies by both economic development and migratory forces, agroforests assert an original but very efficient social takeover of forest richness by local farmers groups. Where natural forests are doomed to destruction, agroforest development re-establishes and maintains diverse and rich forest ecosystems in which farmers are integrated.
In terms of global biodiversity conservation strategy, the strength of agroforests should be clarified. Biodiversity levels achieved in agroforests are still far from those reached by natural rainforests, but they are very impressive compared to other production systems. Agroforests cannot therefore be conceived as substitutes to protected areas of natural forest, but they have a substantial role to play as a supplement, in multiplying for a significant fraction of forest species the opportunities to live and reproduce outside protected areas.
Do agroforests have a future?
With the urgent needs for improved social forestry programs and the promotion of the buffer zone concept for national parks, they have to integrate forest production with forest conservation, and they can no longer afford to ignore rural communities.
From an agricultural perspective, given the failure of many agricultural programs that promoted continuous annual cropping systems in previously forested areas, agronomists have also begun to think of trees as potential vectors for sustainable development.
On the agroforestry side, simple agroforestry associations have been largely tested and promoted, their limits have also been felt, in the fields of biological performance, economic benefits, farmers acceptance, diversification potentials, etc. With the integration of sustainability as a central concept in development, policy makers cannot anymore ignore the environmental consequences of development orientations and programmes they promote.
Trainers and extensionists can now explore their respective countries in search of agroforest systems developed by local farmer and help develop with their colleagues and students a national agroforest knowledge base. Agroforestry trainers have an important role to play in raising public awareness concerning that agroforestry at large and agroforest systems in particular can offer now and in the future.
FAO, IIRR. 1995. Resource management for upland areas in SE-Asia. An Information Kit. Farm field document 2. Food and Agriculture Organisation of the United Nations, Bangkok, Thailand and International Institute of Rural Reconstruction, Silang, Cavite, Philippines. p 207
de Foresta H, Michon G. 1993. Creation and management of rural agroforests in Indonesia: potential applications in Africa. In: Hladik, C M et al, eds. Tropical forests, people and food. Biocultural Interactions and Applications to Development. Unesco MAB Series, No 13, Unesco and Parthenon Publishing Group: p 709-724.
Michon G, de Foresta H. 1995. The Indonesian agro-forest model: forest resource management and biodiversity conservation. In: Halladay P, Gilmour DA, eds. Conserving Biodiversity Outside Protected Areas. The Role of Traditional Agro-ecosystems. IUCN: p 90-106.
Michon G, de Foresta H. 1999. Agroforests: incorporating a forest vision in agroforestry. In Buck LE, Lassoie JP, Fernandes ECM, eds. agroforestry in Sustainable Agricultural Systems. CRC Press, Lewis Publishers: p 381-406.
de Foresta H, Michon G. 1997. The agroforest alternative to Imperata grasslands: when smallholder agriculture and forestry reach sustainability. Agroforestry Systems 36:105-120. Dordrecht: Kluwer Academic Publishers
This edition of The Overstory was excerpted with permission of the publisher from:
de Foresta, H, G. Michon and A. Kusworo. 2000. Complex Agroforests. International Centre for Research in Agroforestry, Bogor, Indonesia.
Publisher contact: International Centre for Research in Agroforestry Southeast Asian Regional Research Programme P0 Box 161, Bogor, Indonesia Tel: +62 251 625415; fax: +62 251 625416; email: email@example.com Web site: icraf.cgiar.org/sea
Printed copies of the original can be purchased from: icraf.cgiar.org/sea/ICRAFPubsList/Bookstore/BookStoreNew.htm#Lect ureNotes
About the authors
Dr. Hubert de Foresta conducts research on agroforests (complex, multistrata agroforestry systems), which are of high economic and environmental value for forest areas in the humid tropics. Now based in Montpellier, he concentrates on the biodiversity aspects of these systems and testing of potential solutions for improving productivity and profitability. Dr de Foresta has an MSc in tropical botany and a PhD in tropical forest ecology from the University of Montpelier. He worked in Congo (1986-1999) on the relationships between slash-and-burn cultivation and natural vegetation, then in Indonesia, first with the SEAMEO-BIOTROP center (1989-1994), where he was in charge of a multidisciplinary research project on agroforestry practices and biodiversity conservation, and second with the ICRAF S-E Asia Regional Office (1994-1999) where he was in charge of the Krui Community-Based Forest Management programme sponsored by the Ford Foundation. He can be reached at: Hubert de Foresta, Chargé de Recherches à l'IRD (anciennement ORSTOM), ENGREF (Ecole Nationale du Génie Rural et des Eaux et Forêts), B.P. 5093, 34033 MONTPELLIER Cedex 01, FRANCE; Tel: (33) 4 67 04 71 41; Fax: (33) 4 67 04 71 01.
Dr. Genevieve Michon conducts research on the interrelations between agricultural societies and forests. Dr Michon has a master's degree in agricultural science from the Ecole supérieure d'agronomie tropicale de Montpellier, and an MSc in tropical botany and a PhD in tropical forest ecology from the University of Montpellier. She worked for ORSTOM in Congo (1986-1987) on the evaluation of the importance of trees and forests in farmers economy in southern Mayombe, then with the SEAMO-BIOTROP centre in Indonesia where she was in charge of a multidisciplinary research project on sustainability of forest resource management through agroforests. Seconded from ORSTOM, she joined ICRAF in 1994, where she worked on the domestication of forest resources, including non-timber forest products and timber, in agroforestry systems. From 1996 till 2001, she led a EU-funded project on the analysis of the transition between extractive systems in natural forests and agroforestry systems in farmlands for the management of forest resources. She is based in Montpellier since 2000 where she leads a research team on the interrelations between forest dynamics and the evolution of forest-dependant societies.
Mr. Ahmad Kusworo is working as a policy analyst. His work examines government spatial planning with a focus on land use, forestry development, and the impact of these on local communities. He was the director of WATALA, an Indonesian conservation non-government organization and a key ICRAF partner in the study and official recognition of the Krui Damar agroforest in Sumatra. He holds a BSc degree in agriculture from the University of Lampung. He completed a policy internship with ICRAF in Bogor and is currently pursuing a PhD in anthropology at the Australian National University (ANU) in Canberra, Australia with field work in Lampung again in collaboration with ICRAF.
Related editions to The Overstory
- The Overstory #93--Trees, Forests and Sacred Groves
- The Overstory #82--Indigenous Knowledge
- The Overstory #77--Tropical Forest Conservation
- The Overstory #76--Ethnoforestry
- The Overstory #64--Homegardens
- The Overstory #51--Expanding Traditional Agroforests
- The Overstory #49--Traditional Pacific Island Agroforestry Systems
- The Overstory #34--Forest Islands, Kayapo Example
- The Overstory #21--Agroforestry and Biological Diversity