The wide range of traditional tree-crop practices in Sri Lanka offers exciting prospects for the further development of agroforestry throughout the country. The deteriorating land-to- people ratio and the ever-declining per capita availability of agricultural land has made agroforestry a promising solution to present-day problems. This article describes several types of traditional tree-crop practices in Sri Lanka.
There is a strong tradition among the people of Sri Lanka when it comes to growing trees and conserving forests. The history of cultivating trees in homegardens, communal tree planting, the protection and management of forests, and the protection and appreciation of wildlife and nature goes back 25,000 years. In chronicles, there are references to communal tree-planting practices, well-organized village communities, and homegardens planted with flowering and fruit-bearing trees. These strong traditions have given environmental stability to large parts of the country, notably in the southwest and central regions. In this light, it would be true to say that in Sri Lanka 'the art of agroforestry is an ancient one, while the science of agroforestry is new'.
Thanks to these age-old traditions, numerous examples of tree- crop or agroforestry practices are found in all the various climatic zones in Sri Lanka. A wide range of species, both trees and crops, are cultivated by means of these methods. The species distribution varies throughout the different regions and communities, as does the extent to which people are dependent upon tree products. The disparity in tree-use practices from one region to another has to do with the nature of the local tree species, the availability of resources, the access of the community to such sources, and traditional technologies and customs. A few of the many tree-crop practices in use in Sri Lanka are described below.
Chena or shifting cultivation, is an age-old form of tree-crop practice in which people clear forest lands in order to grow cash crops. When, in time, crop yields begin to decline, they move on to fresh lands. In this way, forests and crops alternate in a temporal sequence, whereby the main objective is the growing of agricultural crops. All kinds of subsistence and cash crops are cultivated in these chena. In an economic sense this was a simple form of subsistence farming with virtually no external inputs. It was sustainable as long as land was allowed to lie fallow for at least 15 years. Today, however, it is no longer a sustainable form of cultivation, as the fallow period between two cropping systems is becoming ever shorter, and the productivity of the chena is rapidly declining. This is due mainly to the increase in the rural population and the decrease in the area of forest lands**1, resulting in loss of soil fertility, increased erosion, loss of soil structure, and ultimately land degradation. As a result of uncontrolled chena cultivation, extensive areas of natural forest in the Dry Zone have been totally degraded.
From the end of the last century to about 20 years ago, chena cultivation was widespread and regulated by the issue of cultivation permits by agents of the District Government. Before then, the practice was illegal, as the lands that were being cultivated were the property of the government. Today settled agriculture is the norm, and massive hydro-electric irrigation and settlement projects like the Mahaweli Project**2, have led to a decline in chena cultivation. In 1981 the issue of permits was officially terminated, and today there is only sporadic illegal chena cultivation taking place in the natural forest areas of the remote dry zones.
Intercropping of coconut
Coconut is the most widely planted agrobased industrial tree in Sri Lanka, covering 25% (419,200 ha) of the total cultivated area of the country. About 55% of coconut lands are smallholdings, each less than 4 ha in size. Cultivation is concentrated mainly in the coconut triangle in Western Sri Lanka, comprising the districts Kurunegala, Puttalam, Gampaha and Colombo. On most coconuts estates, a variety of different crops (see below) are grown in combination with coconuts. In some areas cattle are allowed to graze under coconut trees.
Food crops (such as tubers, cereals, legumes and fruits), spices and condiments (such as arecanut, betel leaves, chillies, ginger and turmeric), cash crops (like black pepper, cacao, cinnamon, cloves, coffee and nutmeg), and pasture grass are grown under coconut trees. The species preferred by cultivators are bananas, black pepper, coffee, ginger, turmeric, betel, vegetables and pineapple, as these can be grown successfully in shade and provide a good income. The most common crop mixtures in mature coconut plantations are coffee and banana; coffee and pineapple; pineapple and papaya; and banana with coffee and cacao. The overall return from a unit of land is increased by intercropping. The coconut trees benefit from the manure and fertilizers, weeds are eliminated, and the working of the soil benefits both the palms and the crops.
There is a complex relationship between land ownership, supervision and intercropping. The land is in private hands, but in most cases it is cultivated by non-owners to whom responsibility has been allocated. Of the intercropping holdings, 63% are cultivated and supervised by non-owners with the help of non-resident labour, since owners are also involved in other forms of cultivation, such as paddy rice. This agroforestry system has a potential for widespread adoption in coconut areas outside the coconut triangle. Thanks to the growing interest in agroforestry evinced by the scientific community, the Agriculture Department and the Coconut Cultivation Board have received additional government subsidies to promote this practice. As a result, intercropped coconut lands are now increasing by 1000 ha per year.
Tea, coffee and cacao under shade trees
Tea, which covers around 227,900 ha, is cultivated mainly in the central hills, although some is also grown in the wet lowlands of the southwest. The land is owned by the state and by individuals. State-owned estates are managed either by the State Plantations Corporation or the Janatha Estate Development Board. A large number of leguminous and other shade trees are grown by means of this system. Partial shade not only increases the long-term tea yield, it also fixes nitrogen, which enriches the soil (in the case of legumes); creates a favourable microclimate by lowering the temperature; reduces evapotranspiration losses; restricts the impact of wind; controls soil erosion; and yields firewood, timber and organic matter for mulch, thus sustaining soil fertility.
As coffee demands more shade than tea, there are more shade trees on coffee plantations. Coffee is confined to several small estates in a few central districts in Matale and Kandy. The socioeconomic benefits are similar to those provided by tea, and the land tenure system is comparable. The shade tree most commonly used is Gliricidia sepium, which provides partial shade to the coffee plants and enhances soil fertility. Species of Albizzia and Acacia are also planted at wide intervals.
As in the case of tea and coffee, cacao plantations are found on small estates or holdings, mainly privately owned, in the Matale, Kurunegala and Kandy districts. The total area cultivated is around 8,000 ha. The intermediate climatic zone, which receives moderate rains, is fast becoming a highly productive zone for agroforestry crops and trees, and almost all the fallow land in the zone is now subject to intensive sustained cultivation. This system appears to offer quite considerable economic benefits, and many cacao by-products have found their way to the country's urban markets.
Fruit trees in combination with rubber trees
Rubber (Hevea braselensis) covers about 206,000 ha. The shade cast by rubber in the later stages of its growth is quite dense, which restricts intercropping. For this reason, only a few rubber plantation estates have adopted intercropping, generally by means of fruit trees. In the intermediate zone and parts of the wet zone, cacao is underplanted in places where the rubber canopy is not too dense. In many wet-zone areas, pineapple is grown under rubber.
Palmyrah palm and cashew nut
This combination is found in the coastal areas of the Dry Zone and in semi-arid areas in the northern and eastern coastal districts. The Palmyrah palm (Borassus flabellifer) is a multipurpose tree. The trunk provides firewood, the leaves can be used for thatching and as material for parapet walls, and the flowers can be tapped for toddy. Cashew (Anacardium occidentale) is the main intercultivated crop, while Casuarina (Casuarina equisetifolia) species and Margosa (Azadirachta indica) are not only cultivated as windbreaks, but also used for fuel, medicinal use and timber. Almost all land cultivated by means of this system is privately owned. Cashew is a valuable export crop, which also fetches high prices in the local markets. In some areas, Prosopis (Prosopis juliflora) is also interplanted for fuel or as a live fence. All these species--Palmyrah, cashew, Propopis, Casuarina and Margosa--perform well on the semi-arid lands and along the coast.
This tree-crop practice is an ideal form of land use, combining as it does agriculture, forestry and livestock. Trees are grown in a multitiered arrangement, terraced where necessary, and adapted to the local topography. It is a traditional system consisting of the mixed cropping of trees (which yield timber, logs and small pieces of firewood, fodder, fruits, nuts, and medicines) and crops (which yield food, cash and medicines). The entire system provides an ideal microclimate for both humans and animals. It is commonly used not only in Kandy district, but also in the adjoining Matale and Kurunegala districts.
The holdings are small, on average about 1 ha, and as a rule they are privately owned. The gardens are generally owner-cultivated, and the general rule is 'the bigger the farm, the less densely the garden is planted'. The operating costs, which cover weeding, brush-cutting, collecting spices from the trees and from the ground, and hired labour, amount to about Rs. 1,200 per ha. From an economic viewpoint, the system is quite profitable. With better management, such as spacing, fertilization, thinning and the selection of genetically superior trees, the system has the potential for a continuous high level of production and high returns. Among the many crops grown in these homegardens are jackfruit, durian, rambutan, papaya, citrus, avocado plantain, pineapple, passion fruit, mango, breadfruit, coffee, cacao, tea, black pepper, Kitul palm (Caryota urens) spices, yams and fodder grass.
Other homestead gardens
In most other districts of Sri Lanka, notably the lower zone in the western and southern coastal belts, and the low-country dry zone, there are fewer species, the trees are less densely planted, and the homegardens are managed less intensively. In the low-country wet zone, people grow most of the Kandyan homegarden species (with the exception of cacao and coffee), but not so intensively. Fruit-bearing species like rambutan and mangosteen are also seen.
In the homestead gardens, fences of Gliricidia sepium are used, while in the intermediate and dry zones kapok is used (Bombax malabaricum). The canopy cover in this system is not dense, ranging from about 25% to 75% of the area of the homegarden. Animals such as cattle, goats and chickens are reared in these systems; goats are particularly common in the dry zones. Leucaena leucocephala spp. grows profusely in the dry- zone homegardens, increasing soil fertility and providing food and fodder.
In some dry-zone homestead gardens the 'drumstick' tree, known locally as murunga (Moringa oleifera), is grown in the form of fences or hedges. The crown is very light, the pods are a popular and nutritious dish, and the bark of the tree is used for medicinal purposes. Production starts within one year of planting.
In other systems, Sesbania grandiflora is planted. This is a short-lived tree of medium height, which is used mainly in the intermediate dry and semi-arid zones. Local people use the tender leaves and flowers as vegetables. Here, too, production can be expected within one year of planting. It is an important source of green manure and fodder, especially in the dry season.
Pastoralism, forestry and apiculture
These systems are found in the medium-high to high elevations in central Sri Lanka, as well as in the coconut triangle in the southwest. The practice is widespread in the hilly patanas or wet grasslands. The trees grown are mainly eucalyptus, pinus and cypresses. In the coconut areas, cattle are generally raised on coconut lands which are not intercropped to any large extent. However, on certain plantations that are intercropped cattle are raised in paddocks. In some areas, especially in the mid-mountain zone, there is a danger of fire, because the herdsmen burn the dry grass just before the rains, in order to get a new flush of grass for their cattle.
Excellent examples of apiculture are found near the towns of Diyatalawa, Bandarawela and Welimada. Cattle grazing is practiced and bee-keeping is encouraged by the government. The best honey is said to come from Eucalyptus robusta flowers.
This system is restricted to the mangrove forest areas along the coast. The country has around 12,000 ha of mangrove forests which produce timber, firewood, bark, fish and shellfish. Prawns are cultivated in some areas near Negombo, Colombo and Kalutara along the west coast. The mangroves provide spawning grounds for prawns and other shellfish as well as many types of fish. A mangrove park has also been established by the government near Negombo, to demonstrate the benefits of the mangrove forest. Those along the northwestern and eastern coasts are also familiar breeding grounds for indigenous and migratory water birds. Mangrove firewood is used by villagers, and by small industries producing bricks and tiles. Mangrove bark is also produced and removed on controlled tender, permits being issued by the district authorities.
Medicinal trees with pastures
This is an ancient system concentrated in the districts east of central Sri Lanka; the best examples are found near the town of Bibile. The trees, which were first planted in the days of the Sinhalese kings, are scattered in typical savannah grasslands. The lands are state-owned. Aralu (Terminalia chebula), Bulu (Terminalia belerica), and Nelli (Emblica officinalis) are the principal tree species. Cattle-grazing and goat-rearing are practiced on the intervening grasslands. There is a fire hazard in the dry months of May to August, but the trees are capable of withstanding ground fires. Wildlife, including elephants from nearby national parks, move into these areas, but as a rule no damage is done to the valuable medicinal trees.
The wide range of traditional tree-crop practices in Sri Lanka which are outlined above promise exciting prospects for the further development of agroforestry throughout the country. The declining ratio of land to people and the steady reduction in the per capita availability of agricultural land--now 0.27 ha, as compared to 1.64 ha worldwide--has made agroforestry a promising possible solution to the present problems.
Small agroforestry-based cottage industries will keep agroforestry farmers away from the natural forests, which are now under great pressure, and will also discourage people from migrating to already overpopulated urban areas. The development of agroforestry in Sri Lanka has a three-pronged effect: it increases the living standards of the rural poor, improves environmental conditions, and safeguards the ecosystems of the natural forest with their valuable genetic resources.
Agroforestry must be incorporated into national land use planning, to specific districts and agro-ecological zones, and established on a firm scientific footing. To do this, the Forest Department, Agriculture Department and Monitor Export Crops Department will have to work closely with one other on a professional basis, with popular support and a strong political will.
Dr Hemanthi Ranasinghe
Sri Lanka Resource Centre for Indigenous Knowledge
University of Sri Jayewardenapura
Prof. R. Ulluwishewa, Director
Nugegoda, Sri Lanka
Address until September 1996:
School for Forestry and Environmental Studies
8 Prospect Place
Tel: +1-203-432 5153.
Fax: +1-203-432 3929.
**1 In 1900, the amount of high-canopy natural forest cover was 70% of the land area of the country (65 km2). By 1956, however, the natural forest cover had dwindled to 44% of the land area of the country. In 1995 the forest cover of 23.5% of the land area of the country.
**2 The Mahaweli project, initiated in 1965, was the largest irrigation and settlement project in the country. Farmers from all over the country were settled mainly in the Dry Zone of Sri Lanka; they were given 2.5 acres of paddy and 0.5 acres of land for crop production.