|Agro-forestry in the African Humid Tropics (UNU, 1982, 162 pages)|
|Taungya systems from biologiocal and production viewpoints|
Aiah P. Koroma
Forestry Division, Ministry of Agriculture and Forestry, Freetown, Sierra Leone
The paper briefly describes the agriculture and livestock industry, the method of afforestation by the taungya system, and the evolution of silvicutture and agro-forestry in Sierra Leone.
Two factors necessitated the introduction of agro-forestry- namely, the rapid rate of deforestation of unreserved forest lands due to increased agricultural activity, and the reluctance of landowners to set aside any more lands for forest conservation, which did not yield immediate financial returns.
The acute and increasing demand on forest lands is being alleviated by modified forest management and silvicultural techniques, which include various agricultural crops as understoreys in forest plantations. The idea is to conserve the vegetation, minimize soil erosion, and encourage active participation of farmers in the production of both food and wood on the same piece of land.
Sierra Leone has a tropical climate with high temperatures, high humidity, and heavy rainfall. The rainy season extends from May to October, with the heaviest rains falling in July and August. The rainfall decreases from the coast inland, e.g., 3,800 mm in the coastal city of Freetown to 2,100 mm in Kabala in the far north-east.
Topographically, the country can be divided into three main zones: (1) the low-lying, swampy coastal area; (2) the interior plateau (about 450 m in elevation); and (3) the mountain ranges of the north-east with peaks of over 1,800 m.
The total area of Sierra Leone is 72,326 km², and this can be classified into agricultural land (60 per cent), pastures (18 per cent), mangroves and inland swamps (8 per cent), forest (4.25 per cent), and other (9.75 per cent).
Agriculture is the largest sector of the economy, but, in spite of the economic and social measures applied, this sector has the lowest income level. Annual productivity per worker is estimated to be Le 100,* or less than half the average (Le220) for all sectors. This figure compares with Le880 for mining and between Le330 and Le900 for the other sectors. The poor productivity of the agricultural sector indicates the need for more effective approaches and practices. The current farming systems need to be reevaluated and upgraded.
In the northern half of the country, the long dry season limits production to cattle and annual crops, whereas the south has rainfall and climate suitable for the production of cocoa, coffee, and oil palm, which together form the backbone of agricultural exports. The important food crops grown in Sierra Leone are rice, sorghum, millet, maize, cassava, sweet potatoes, groundnuts, and sesame, with rice being by far the most important. It accounts for more than 75 per cent of the area under food crops and provides employment for more than 80 per cent of the farming population. Yearly production is currently estimated at 800,000 tons.
The total area under upland rice in 1970 was about four times that in swamp rice (236,400 ha compared with 60,800 ha), even though the average yields of the former are generally much lower and are showing a downward trend owing to shorter fallow periods.
Traditionally, upland farming has consisted mainly of the bush fallow or grass fallow system in which a few years of cropping is followed by an interval of fallow-8-12 years in the Eastern Province, 4-6 years in the Northern Province. After the fallow, the natural groundcover is cut and burned. Rice seed is mixed with other upland crops such as maize, guinea corn, millet, sesame, pigeon pea, okra, beans, etc. and is broadcast by the farmers over a series of separate strips. The rice is harvested first. Cassava, the major root crop in the country, is planted as the last crop before the land is fallowed.
Although swamp rice farming has been found to be more profitable than upland crop farming, many farmers are reluctant to adopt it, either because they do not know about swamp rice farming or because they prefer upland farming for the variety of crops it produces.
Coffee, cocoa, and oil palm are the primary agricultural exports; therefore, tree crops constitute an important source of foreign exchange. The total area under oil palm is estimated at about 4.5 million ha in natural stands, varying in density from 15 to 150 trees/ha. Under cocoa, there are about 2,240 ha, confined mostly to the Eastern Province. Other tree crops are cola nuts, cashews, coconuts, and citrus fruits.
The growing of tobacco started not so long ago. In 1961 there were 24 tobacco farmers and by 1971, more than 15,000. Cultivation, which was originally confined to the Northern Province, has recently been introduced into the Southern Province.
The livestock industry is centred on cattle. The cattle population is concentrated mainly in the northern part of the country, which comprises vast tracts of natural savanna pastures interwoven with gentle slopes. The mild climate and sparse population increase the potential production. The cattle are N'dama, their estimated numbers being between 250,000 and 300,000. Nomadism is a basic social and economic problem, and settlement schemes by the Livestock Division have been unsuccessful.
The estimated population of smaller livestock in the country for the year 1975 was 62,000 sheep and 175,000 goats. They are spread throughout the country, but the largest flocks are kept by cattle owners of the Northern Province.
Agro-forestry: From Modest Beginnings
During the mid-1940s the native administrations became interested in forestry and began to plant timber-producing trees, often on roadside strips not more than 170 m wide. This effort led to the examination of the afforestation techniques and the search for ways to reduce the costs of clearing the bush fallow for the trees and reduce the long waiting period from the time the plantation was established to the time it began to yield revenue.
Taungya was considered as a means of reducing time and costs involved in establishing the forest. The first real attempt to establish forest plantations by the taungya system was made in the late 1930s, using 50 per cent indigenous species and 50 per cent of the exotics, Gmelina arborea, Tectona grandis, and Cassia siamea. It was observed that the 50 per cent indigenous and 50 per cent exotic species mixture was not a useful proposition, as the exotics grew faster and the indigenous species lagged behind.
Subsequently, underplanting the established Gmelina stands with local species was tried. The aim was that if any of the more valuable indigenous species showed signs of succeeding, thinning in their favour would be resorted to later. In general this was a reaffirmation of the policy of preferring indigenous species to exotics. But Gmelina, being a fast-growing species, eventually swamped all the indigenous species.
In the early years of the system, there was one notable effort to reduce the time between plantation establishment and plantation exploitation through the introduction of an understorey of cocoa. Demonstration and observation plots were established under various light conditions. The plots were successful, and afforestation along these lines was gradually extended as the local administration nurseries produced more planting stock. The cocoa, which replaced part of the natural understorey, yielded quick monetary returns as minor forest produce. Unfortunately, as a result of staff changes and the difficulty of growing cocoa in unsuitable soils, these experiments were neglected and eventually discontinued.
The taungya system, however, is still in operation and is based on co-operative efforts between the government and farmers. Each year planting areas are demarcated in December or January and invitations issued through the Paramount Chiefs to the farmers who formerly owned the land. It is the original landowners who have the first rights to farm the land in exchange for clearing the bush fallow and following the planting guidelines set out by the government. Only the original landowner can reject the offer to farm, and pass on the rights to someone else.
After the bush is felled, the cut vegetation is allowed to dry and is then burned about March-April. The forestry department lists crops that are allowed to be cultivated and lays down other requirements. In June-July, the young forest trees are planted by the forestry staff, and this is done after the farmer has planted his own crops.
Spacing for the forest trees varies according to site and species to be employed. The general trend is toward wide spacing, e.g., 2.5 x 2.5 m, 3 x 3 m, and 4.5 x 4.5 m for Gmelina arborea, Terminalia ivorensis, T. superba, Cordia a/liodora, and Nauclea diderrichli.
The principal agricultural crop used in taungya is rice, but farmers are allowed to sow maize, guinea corn, peas, sorghum, cassava, and okra. During this time, the farmers tend the young trees in addition to their agricultural crops.
After the second, and sometimes the third, year the farmer is allotted another plot. In most cases where there is no land hunger and in remote areas where the forestry department is obliged to carry out rapid afforestation, the farmers are the forestry employees. Forest villages are built for them, and all the agricultural crops they cultivate belong to them.
The idea of simultaneous production of timber and agricultural crops on the same piece of land was revived as a result of certain developments in the country during the implementation of the first five-year national development plan. These developments included the rapidly diminishing unreserved high forest as a result of the rising population, the return to the land of people previously engaged in mining, and the government emphasis on increasing food and cash crop production to conserve and obtain much-needed foreign exchange.
Most land in the country is held communally with individual right of usufruct: there is no formal tenure except on the Freetown Peninsula, i.e., the old colony area. Also, there was a growing feeling in the country that landowners who had given up land for forest reserves and protected forests generally did not receive adequate or immediate compensation. Thus, it became extremely difficult for the government to obtain additional land for forest plantations or even to retain the existing forest estate.
The forestry department, therefore, began in 1976 to introduce cocoa, coffee, and cola, as understoreys in Terminalia ivorensis and T. superba plantations. Initial experiments at Kasewe Forest Reserve in the late 1950s had proved satisfactory, and the indications are that coffee will soon become the main understorey in extensive areas of wide espacement plantations in forest reserves and the lineplanted areas in native administration forests.
These perennial crops are being introduced as understoreys at spacings of 7.5 x 7.5 m, 9 x 9 m, and 10.8 x 10.8 m such that the final crop will be 178,121, and 85 stems/ha respectively when the plantations are between 12 and 15 years old. It is hoped that when the agricultural crops have outlived their usefulness (about age 30), the whole area will be clear felled and replanted by the taungya system. Maintenance from the time the agricultural crops are planted will be carried out by the farmer (the original landowner or holder), to whom the plantation would be leased on payment of an annual rent to be mutually agreed upon. Cassava and sweet potatoes have also been recently introduced in nearly mature T. ivorensis, T. superba, C. alliodora, and G. arborea plantations. No measurements of yield have so far been made.