TROPICAL SECONDARY FOREST MANAGEMENT IN HUMID AFRICA: Reality and perspectives
An introductory paper
Written by
Dominic
Blay
Forestry Research Institute of
Ghana
University Box 63
Kumasi,
Ghana
FOR THE
FAO/EC
LNV/GTZ
WORKSHOP ON TROPICAL SECONDARY FOREST MANAGEMENT IN AFRICA:
Reality and
perspectives
In collaboration with ICRAF and
CIFOR
Nairobi, Kenya, 9-13 December 2002
Secondary forests currently constitute a large proportion of the forest cover in Africa. If properly managed they have the potential to provide important environmental benefits and contribute significantly to poverty alleviation especially in rural communities. They can also reduce the pressure on the few remaining areas of primary forest. Unfortunately, the management of secondary forests has not been given significant attention in most African countries with the result that secondary forests are not part of forest management systems. It is for this reason that FAO, in collaboration with ICRAF and CIFOR and with financial support from the Governments of the Netherlands and Germany, organized a workshop to draw the attention of all stakeholders to the need and potential of the sustainable management of secondary forests in Africa.
This background paper highlights some main issues on secondary forests as a basis for discussion during the workshop. The issues include the concept of secondary forests, causes and functions of secondary forests, typology and extent, potential of secondary forests as well as the socio-cultural, ecological, technical and politico-institutional aspects of secondary forest management.
Secondary forests from the African perspective are the forests that grow when farmlands are abandoned. Richards (1966) defines secondary forests as secondary vegetation communities, which replace primary forests.
Blaser and Sobagal (2002) defined secondary forests as the woody succesional vegetation that regenerates after the forest cover has been removed by human intervention. Secondary vegetation appears to be a chaotic wilderness of several trees, shrubs, climbers and tall herbaceous plants, is always more or less unstable and consists of successional stages. If undisturbed by grazing, tree felling and frequent fires, this secondary vegetation is slowly invaded by primary forest trees and can eventually develop into a community similar to that which originally occupied the site. The speed of change depends on the availability of seed trees and health condition of the forest. For a few years it is usually rapid, but later it becomes much slower and the whole process of recovery probably extends over centuries rather than decades. If the secondary vegetation is subject to recurrent fires, grazing or other disturbances, deflected ('retrogressive') succession sets in leading to apparently permanent biotic climaxes.
Secondary forest is different from degraded primary forest. In degraded forest the initial forest cover of a primary, old-growth or managed forest has been affected by unsustainable, excessive wood harvesting or by such intensity of extraction of NWFPs, that its structure, processes, functions and dynamics are altered beyond the recovery potential of the forest ecosystem. It is also different from degraded forest land where the initial forest cover has been removed completely and physical conditions have been severely impacted by over-harvesting, repeated fire, excessive grazing or other intensive disturbance from alternate land uses. Such conditions inhibit or delay forest re-growth after abandonment. The land cover is generally dominated by grass, low shrubs and creepers, or the land is barren. A high degree of soil degradation and lack of seed sources are the main factors that hamper the natural succession towards secondary forests.
Unsustainable shifting cultivation is probably the most important cause of deforestation in tropical Africa. Shifting subsistence agriculture ('slash-and-burn' or swidden farming) is practised in almost all parts of Africa. Although the methods of shifting cultivation vary in detail in different regions and cultures, the general procedure is always similar. A patch of forest is felled, usually by a family or small group. The size of the clearing ranges between about one and fifteen hectares, depending on the amount of labour available and productivity of the site. Often, for superstitious or other reasons, some of the larger trees are retained. The brushwood and fallen timber are usually, but not always, burnt when dry enough. Crops are then planted, the commonest being cassava (Manihot esculenta), maize, yams (Dioscorea), cocoyam (Colocasia esculenta), plantains (Musa) and sweet potatoes (Ipomoea batatas) or mixtures of these. Often smaller quantities of fruit trees and other edible or useful plants are also grown.
The soil soon becomes impoverished and infertile because the humus is rapidly destroyed by exposure to the sun and the ground receives little cultivation and no manure. Weeds and diseases become increasingly difficult to control and crop yields decrease. After about three years the field is abandoned. The period depends on the extent of leaching and erosion as well as the inherent fertility of the soil. Secondary succession follows after abandonment. During this period, soil fertility is gradually restored and after a fallow period, usually of about ten or more years, the developing secondary forest can be cleared and cultivated again.
Plantation agriculture, which in most instances proved to be little more permanent than shifting cultivation, is another cause of secondary forest. After the plantation agriculture is abandoned because of soil impoverishment, animal pests, plant diseases or other reasons, large areas of secondary vegetation develop on the sites. Individuals of long-living crop plants, such as oil palms and fruit trees, often survive in secondary vegetation as relics of past cultivation.
Selective logging creates a very irregular forest structure, with numerous large gaps filled with climber tangles or dense stands of young trees. In modern mechanised forest exploitation a wide range of species is extracted. When the timber is required for 'wood chips' (pulpwood) almost all the trees are usually removed. Even when logging is selective large numbers of trees are damaged or destroyed incidentally. Secondary forests develop in the gaps created during logging. Logging also opens up the forests that are then invaded by farmers.
Fires, mostly anthropogenic, are now one of the commonest causes of rain-forest destruction. Fires are often set deliberately either for farm clearing or for driving out animals during hunting, which sometimes gets out of control. Fires can also be set unintentionally by palm wine tappers or smokers leaving butts of cigarettes unextinguished in the forest. In undisturbed rain forest single trees or small groups are often burnt by lightning. Extensive fires occur only in periods of exceptional drought.
Natural causes of deforestation include wind, landslides and volcanic eruptions. Wind-throws of a few hectares in extent may be seen in most rain forests. Secondary forests invade these deforested sites.
Two major types of secondary forest are recognized in Ghana, based on the stand age: secondary forest in the early stages of succession locally called mfofo, and the late successional stages called kwaeye. However, a typology based on the underlying causes that create conditions for the development of secondary forest was proposed by Chokkalingam and de Jong (2001) (see also Blaser and Sobagal, 2002):
1. Post-catastrophic secondary forest.
2. Post-extraction secondary forest (resulting from timber mining) referred to here as degraded primary forests.
3. Swidden fallow secondary forest (part of rotational swidden agriculture).
4. Secondary forest gardens (secondary forest with a large component of enrichment planting).
5. Post-abandonment secondary forest (which is the main type throughout the tropics).
6. Rehabilitated secondary forest (forest re-growth with rehabilitation of degraded lands).
Such a classification may be applied generally to landscapes and biogeographic regions and over a wide range of biophysical and social environments. A typology linked to causal agents allows the development and selection of site-specific management systems and strategies which in turn can guide the different secondary forest categories along sustainable pathways by addressing the underlying disturbance and land use dynamics from which they arise.
The author, however, believes that a typology based on the seral stages, as used by the local communities in Ghana, will be more appropriate. This is because these seral stages have definite vegetational composition that can easily be identified and used to classify the secondary forests.
Secondary forests now constitute a large and ever-growing proportion of forest cover in Africa. Unfortunately, the magnitude of forest regeneration (particularly secondary forest re-growth or re-growth of abandoned lands) is not well documented. Improving the accuracy of these estimates remains an urgent and challenging task.
FAO (1995) estimated that 532 million ha, or 29 percent of the total tropical forest area, were degraded. If the ratio is assumed to be the same for Africa, with the total forest cover for Africa of 705,502,000 ha in 1990 and 649,866,000 ha in 2001 (FAO, 2001), then the degraded forest landscape, including secondary forests, was 196,700,650 ha in 1990 and 181,962,480 in 2001. If it is estimated that about 40 percent of the degraded landscape is secondary forest, then the estimates for 1990 and 2000 will be 78,680,260 and 72,784,992 ha, respectively. Blaser and Sabogal (2002) mentioned that degraded primary forests and secondary forests in Africa were 175 million ha in 2000. If it is estimated that 40 percent of this figure will be degraded forests, then the estimated area of secondary forests will be about 87 million ha. FAO (2001) gives the total forest cover for Africa for the year 2000 as 649,866,000 ha and the plantations as 8,036,000 ha. Thus the natural forest cover is 641,830,000 ha, with 256,732,000 ha secondary forest (estimated 40 percent of total natural forest cover).
Secondary forests are increasingly becoming the predominant forest type in many countries in Africa, and will gradually have to fill the roles of former primary forests. Therefore, secondary forests should offer many of the same benefits that primary forests provide - from non-timber forest products (NTFPs) to environmental services. The current uses of products from primary and secondary forests offer potentials for improved use of the products from secondary forests.
Secondary forests have a high potential to contribute to poverty alleviation of rural communities through NTFPs, most of which are obtained from secondary forests. NTFPs provide small but significant sources of income, particularly for women and for families that do not have access to agricultural markets. NTFPs also provide critical supplies of food during periods when agricultural crops fail or are otherwise scarce.
Secondary forests also provide NTFPs that play an important role in the livelihoods of African households, providing a source of food, medicine, building and craft materials, other household needs, services and income.
Many plants or plant parts are used for food, medicine, aromatics, cosmetics, colorants and forage, such as mushrooms, tubercules, legumes, leaves, bark, fruits, juice, seeds, oils and gums.
In most southern African countries, fruits contribute significantly to people's diet, providing vitamins and minerals. Only in Botswana are fruits not among the most important NTFPs. The variety of fruits is enormous, and no species can be identified as the main one for the entire sub-region.
In Angola, Botswana and Zambia, edible roots and tubers are important NTFPs used as food and drinks. In Zambia, due to food shortage in times of heavy rains or droughts, the importance of roots has increased, as they are important to food security. In the region, information exists for Raphionacme burkei (Botswana), Coccinea rehmannii (Botswana), Rhynchosia spp., Satyria siva, Rhynchosia insignis, Colocasia edulis and Dolichos ellipticus (all in Zambia). In Mozambique, roots and tubers are consumed only occasionally.
Mushrooms, found in the miombo ecosystem, are collected during the rainy season. They are marketed both in Mozambique and Zambia, while in Namibia they are relevant only for subsistence.
The oil palm Elaesis guineensis is most widely exploited in West Africa, especially in the southern humid parts of the sub-region (in particular Ghana and Nigeria). The fruits and kernels are used for the production of edible oils and palm wine. Probably 10 percent of the total energy consumed in West Africa is derived from palm oil based products, which are also an important source of vitamin A. In southeast Nigeria, for example, 90 percent of the population regularly consumes palm oil. Other important edible plants from the humid parts of the sub-region are cola nuts (Cola nitidia, C. acuminata) and bush mango (Irvingia gabonensis).
Construction poles, binding material, laths, tools and fuelwood and charcoal are products that place a heavy demand on the resources and therefore also on secondary forest. Crafts and other household uses include wrapping leaves, rafia thatch, cane products, rattan, mats and chewsponge
Animal-based products include bushmeat, living animals, trophies, bee products (honey and wax), caterpillars, snails, ornamentals and medicinals. Traditional beekeeping is a common practice in southern Africa in general and in Mozambique, Swaziland, Zambia and Malawi in particular. In these countries, honey and beeswax production depends entirely on natural forests as a source of nectar. Major tree species providing bee fodder include Brachystegia spp. (Zambia and Mozambique), as well as Marquesia macroura, M. acuminata, Syzygium spp. and Julbernardia spp. (Zambia).
In the rural areas of Ghana, approximately 75 percent of the population consumes wild animals on a regular basis. Comparable figures are available from southern Nigeria, where 80 percent of the population consumes bushmeat, providing 20 percent of the animal protein requirements. In Liberia, bushmeat contributes 60-90 percent to the provision of animal proteins. In Guinea, bushmeat consumption reaches 2 kg/person/year in urban and 4.4 kg in rural areas. In Burkina Faso, the population consumes 1 kg of bushmeat per year and the national trade is supposed to reach US$ 880 000 to 2.4 million. The high demand and appreciation of bushmeat is highlighted by the fact that in Nigeria, for example, bushmeat is more expensive than products derived from domesticated animals.
Traditional medicine is an essential part of the health care system in most parts of Africa, where synthetic pharmaceutical medicines are not available to most of the population due to high prices and/or lack of supply. The traditional use of plants for medical care is of high socio-economic importance in most West African countries (Biodiversity Support Programme, 1993). In Ghana, more than 80 percent of the population uses medicinal plants. In Nigeria, over 90 percent of the rural and over 40 percent of the urban population depend on traditional medicine. Medicinal plants are used by the population itself and by traditional healers. The importance of traditional medicine is also highlighted by the number of traditional healers as opposed to that of western-trained medical doctors. In Ghana (Kwahu District) and Nigeria (Benin City), the ratio of medical doctors to traditional healers is estimated to be 1:92 and 1:149, respectively. Traditional healers are already officially recognized in countries like Nigeria and Ghana, where 3 360 healers are officially registered, and in Burkina Faso, where some 300 traditional healers allegedly work.
A wide range of species is used as medicinal plants. In southern Africa a variety of medicinal plants is used. The plants that may be referred to as traded key species are Warburgia salutaris (Mozambique, Swaziland, Zimbabwe, South Africa), Harpagophytum procumbens (Botswana, Namibia) and Harpagophytum zeyheri (Namibia). Apart from these, there is a wide range of medicinal plants that are specific to the respective countries. In the humid parts of West Africa, chewsticks derived from Garcinia afzelii and G. epunctata in Ghana and Nigeria and Lophira lanceolata in Guinea (national consumption: 100 million pieces/year) are relevant medicinal plants.
Mostly poor and marginal people also trade NTFPs to obtain an income. A multitude of species is used for subsistence, but only selected species for important uses are commercialized at national and international levels. Traded edible plants include the fruit of Irvingia gabonensis (Bush mango, mostly used for the extraction of edible oils), Dacryodes edulis (Safou), Cola acuminata (Kola, seeds), Coula edulis, Elaeis guineensis (Oil palm, edible oil), Piper guineesis, Xylopia aethiopica, Aframomum spp. and Gambeya africana, and the leaves of Gnetum africanum and G. buchholzianum.
A recent survey in the forest zone in southern Ghana indicated that 38 percent of rural households had at least one person generating some income from forest products. An aggregate employment in forest product activities was growing at 6.9 percent per year. In six countries surveyed recently in southern and eastern Africa-Botswana, Kenya, Lesotho, Malawi, Swaziland and Zimbabwe-about 42 percent of an estimated 763,000 persons were employed in small-scale production or trading in grass, cane and bamboo products.
In the southwest and northwest provinces of Cameroon the value of NTFP production and marketing exceeded US$19 million in 1999 and contributed 2.8 percent to the regional economy. In contrast, timber in this predominantly logged-over area contributed 5 percent and agricultural crops 27 percent.
In spite of these benefits, NTFP gatherers receive relatively low returns because they use rudimentary technologies for collection and pre-processing and are often not involved in processing and distribution. There is a potential to significantly increase the income of people involved through improved technology for collection and local processing and reorganization of production and marketing. Increased technologies can improve harvesting techniques and increase productivity and may also improve resource sustainability. Changes in technologies can produce new types of activities and products and render existing ones less competitive.
In addition to local trading in NTFPs, the export of NTFPs is reported for medicinal plants, living animals, edible plants (e.g. mushrooms, Gnetum africanum, Garcinia klaineana, Irvingia gabonensis, Dacryodes edulis, Piper guineensis, and Rauwolfia vomitora), rattan, bee products, gums and ornamental plants. Main export destinations are Europe, the United States and neighbouring countries (Ruiz and Arnold, 1995).
Secondary forests are sources of important timber species and other species used for carving and the manufacture of household items. Some of the species include Triplochiton scleroxlon, Ceiba pentandra, Daniella ogea, Lophira alata, Milicia excelsa, Nauclea diderrichii, Terminalia ivorensis, Terminalia superba and Alstonia boonei. The timber of other species of secondary forests has economic potential. For instance, until recently Ceiba pentandra did not have any economic use in Ghana. However, currently it is one of the very important economic timber species. Thus, although the wood of early seral trees is soft with low density, it may have economic value in the future. Gregarious pioneers such as Musanga could be used as pulpwood.
Secondary forests can play an important role in carbon sequestration programmes if they are included as an element in international carbon trade markets. Secondary forests on smallholders' farmland or on community lands have the potential to alleviate poverty through the Clean Development Mechanism (CDM) of the Kyoto Protocol.
Young secondary forests are characterised by very high growth rates and sequester more carbon safely than many forest plantations. During the last round in Marrakech prior to the current session held in New Delhi in October 2002, negotiators decided that those countries could meet part of their commitments to reduce carbon emissions for 2008-2012 by financing afforestation and reforestation in developing countries. After 2012 other types of forestry activitiy such as conservation and reduced impact logging might also qualify as CDM projects. Thus, secondary forests on farmlands and in community forests offer greater benefits for rural livelihoods. Incentives for retaining stand and soil carbon stocks could be justified for those secondary forests that are about to be reconverted to agriculture. Prevention from conversion to agricultural use could be a payable service option.
Although small farmer and community CDM forestry projects appear viable from an economic perspective, they are likely to be more expensive than large-scale projects (Smith and Scheer, 2002). That is because of the high cost of organizing and monitoring large numbers of small farmers and the lower productivity of their forestry activities. This means that if governments want small producers to benefit from CDM they will have to take steps to ensure that they can compete effectively with the larger players.
National parks and other kinds of protected area serve a vital function in conserving biodiversity. However, with a major part of the biodiversity existing outside protected areas, it is necessary for biodiversity conservation to extend beyond national parks and other protected areas. Therefore, with secondary forests currently constituting a large proportion of the forest cover, they potentially conserve much of the biodiversity. A secondary forest in Ghana at first enumeration had 292 trees/ha. After one year there were 2007 trees/ha and five years later this number had been reduced to 752 trees/ha (Swaine and Hall, 1983).
However, it shows that secondary forests have a high biodiversity potential. For biodiversity conservation, buffer zones could be established around high biodiversity areas, abutted by production areas for use by local communities.
Secondary forests in cultural sites such as sacred groves and along fringes of rivers, on hilltops and other sites of interest can be of eco-tourism interest.
Secondary forests protect soils from erosion and protect the catchments of many streams and rivers to provide regular supplies of water to local and urban communities. Water companies use water from these areas to provide towns and cities with water, and charge for the water they provide, but they do not pay for the protection of the water catchment provided by the forests. These and other services provided by secondary forests could be costed and charged for. Part of the money could be used as an incentive to local communities and individuals to protect and maintain secondary forests.
Conservation International, through an NGO in Ghana, started a pilot project with a cocoa buying company, Kuapa Cocoa, to pay double the price for a kilogram of cocoa to farmers who have substantial areas of secondary forest surrounding their cocoa farms.
Farmers value secondary forests as fallow for recovering soil fertility. To establish their farms, farmers therefore clear secondary forests in early, or more preferably later, stages of succession.
Secondary forests have a wide range of stakeholders (Table 1). Within and between these groups there are differences in interests, perceptions, needs and conditions. The differences may be competing or mutually exclusive. For instance, loggers most often tend to destroy the farmers' crops during harvesting and extraction of logs from the forest where farms have been established. Farmers tend to burn all timber trees on their land during site preparation to prevent their farms being destroyed by loggers. This impacts negatively on the survival of the forest. There is therefore an urgent need to involve all stakeholders in the planning of management strategies to take care of different interests and needs.
Secondary forests comprise various stages in the process of succession. The pace at which succession proceeds is determined by a range of factors, including the agent, intensity, size and duration of the perturbation, the distance to primary forest seed sources, the availability of fauna and other dispersers, site conditions (e.g. local topography and climate, soil characteristics and light availability) and the natural regeneration capacity on site (seed bank, root and stump re-sprouting).
Table 1: Stakeholders of secondary forests and their specific interests
Stakeholder |
Interest |
Small farmers |
- Use secondary forests for farming to grow crops and to provide the family with economic security |
Hunters |
- Use the secondary forests as their hunting grounds |
Traditional healers |
- Collect medicines for treatment of diseases |
Foresters |
- Interested in managing forests for the sustainable flow of their goods and services and the maintenance of the biological functioning of their ecosystems |
Loggers |
- Interested in harvesting commercial timbers to produce wood products |
NWFP collectors and traders |
- Collect and trade in NTFPs both locally and internationally |
Communities and indigenous peoples |
- Want more economic benefits from forests, guaranteed access for hunting and harvesting forest NTFPs, fallow lands with fertility for farming, protected watersheds for continued water supply |
Politicians |
- Interested in the forests for agriculture or logging which creates immediate jobs, prosperity and tax revenues for government; also temporarily relieves the pressures of need for farm land, jobs and poverty alleviation |
International community |
- Concerned about sustainable economic growth, the future of a world heritage, preservation of forests and their biodiversity |
NGOs, environmentalists |
- Concerned about preservation of forests, conservation of biodiversity and possible negative impacts of development (e.g. flooding, climate change) |
One of the most notorious characteristics of secondary forests is their high floristic heterogeneity: between stands only short distances apart, both in the canopy and in the understorey. This is mainly due to phenological variations of colonizing species at the moment of land abandonment (fallow period), the type of regeneration (re-sprouts versus seeds) as well as the presence of different species of remnant trees, which can influence species composition. At the regional scale, however, abiotic effects such as differences in rainfall, elevation and geology of the substrate mostly determine the rate of succession.
Another distinguishing feature of 'typical' secondary forests is that they contain relatively few very large trees and have a lower canopy than primary forests on similar soils. Most early seral (pioneer) trees seldom grow to more than 20-30m in height and about 90cm in diameter, while primary forest trees of the upper canopy commonly grow to 50m or more and to a diameter of >1m. The canopy of secondary forest is generally more even than that of primary forest. The structure of secondary forest varies greatly. When very young the abundance of saplings and climbers generally gives it a dense tangled appearance and makes it difficult to penetrate. After a few years, particularly on abandoned cultivated land, even-aged stands of trees of remarkably regular structure often grow up. These may consist of a single fast-growing species such as Musanga cecropioides. All these trees are light-demanding and short-living, are dominant for only a single generation and are unable to regenerate in their own shade. When they die they are replaced by a mixture of less fast-growing, more shade-tolerant and longer-living trees, some of which are seral and some primary forest species. In contrast to seres following cultivation, the secondary vegetation developing after logging, at least during its earlier stages, is very irregular in structure. Damaged survivors from the former forest are scattered among climber tangles and patches of 'razor grass' (Scleria spp.), and dense stands of saplings may be present. Such vegetation grades into the 'depleted forest' mentioned earlier.
Secondary forests, even when fairly old, differ in floristic composition from primary forests, although secondary species (including early pioneers) often occur, usually in small numbers, in natural gaps in the latter. Zanthoxylum (Fagara) macrophyllum, Harungana madagascariensis, Pycnanthus angolensis, Alstonia, Ficus, and many other genera, have a similar significance. It is often suggested that secondary forests always have fewer species per unit area than primary forest, especially of trees, but this is not necessarily so. The species richness of secondary forest probably depends on age and other factors. Data for valid comparisons are scarce.
In the early stages of secondary succession the number of species per hectare on small plots rises rapidly, but after a few years the increase is slower. In old secondary forests the number of tree species on plots of 1-2 ha may be as great as in comparable samples of mature forest in the same region. In very extensive areas of secondary forest the number of species is probably less than in primary forest because secondary forest species usually have wider geographical ranges than primary forest species
It is noteworthy that semi-deciduous and deciduous tree species characteristic of seasonal climates are often common in secondary rain forest. In West Africa, for example, Milicia excelsa and other mixed semi-deciduous forest trees often occur in clearings and young secondary evergreen seasonal rain forest. Bombacaceae are also often found in old and middle-aged secondary forests (Budowski, 1970).
The availability of different regeneration mechanisms determines the speed and course of secondary succession. Vegetative sprouting, such as from tree stumps and root fragments, form an important component in the regenerating vegetation, both in dry and moist forests. Regeneration from seed is, however, the main regeneration mechanism for the widely-dispersed pioneer species, especially after repeated fallow-cultivation-fallow cycles over long periods of time. In such circumstances, the future tree flora will be formed mainly by that subset of species capable of resprouting repeatedly from vegetative parts. In highly fragmented landscapes, in particular, re-sprouting is perhaps the principal mechanism of regeneration of remaining primary forest species.
The productivity of secondary forests may vary in relation to factors such as site conditions (in particular topsoil and humus conditions), time since settlement and, more specifically, the number of crop-fallow cycles at a particular site, the type and intensity of land use during the cropping stage, and the prevalence of disturbances such as accidental burning during the fallow stage. As succession progresses, total stem density tends to decrease and the stand increases in height, basal area and volume. The first 15 years or so of succession are characterized by rapid biomass accumulation (up to 100 t/ha per year). The relative amount of woody biomass increases rapidly during the first 15-20 years, followed by a steady but slower rate until maturity
Secondary forests are also normally found on community lands or on land of smallholders. The management therefore should be part of the farming system or communal property. The participatory planning process, recently introduced into the management of primary forests, should be extended to secondary forest management. This will highlight the role of this resource as a common property of local communities and its use in farm production systems, and will clarify the factors that underlie decision-making by farmers. It will also provide information on the roles and expectations of farmers and communities in relation to the forestry component of farm production, and identify possible options for secondary forest management.
The age and composition of the forest, the history of the site, the local conditions and the aim of management are additional factors to be considered in the participatory process.
While there has been very little technical management of secondary forests, the following are options that could be pursued. These options will vary from field to field and farm to farm, depending on the biophysical characteristics, resources available (land, labour, capital), markets, opportunity costs, etc.
Fallow may be the single most important use of such vegetation at the present time, but the sustainability of slash-and-burn agriculture appears questionable in current socio-economic conditions (Guariguata and Finegan, 1997). Therefore if the fallow is to be managed as part of subsistence/swidden systems this will require techniques that allow short fallow periods that will increase agricultural productivity. Leguminous woody species, such as Gliricidia sepium and Albizia spp., will contribute towards a more rapid recovery of soil nutrients and should be planted as fallow trees during the fallow period.
If management has to produce forest products for subsistence use or sale, then the emphasis should be on locally desired tree species which grow fast, from seed or coppice re-growth, are capable of producing a marketable product within the fallow period, are tolerant of shade in plants other than trees, and have multiple uses. These species can be planted through the taungya system during the crop phase.
In a management regime aimed at the sustainable production of timber and/or NTFPs, farmers will probably have to take land out of the crop-fallow cycle, intensify agriculture, or use areas of low productivity for farming. In any case, the change in land use must generate a benefit which is greater than that received in an alternate use of the resource. The multiple-use of many species growing in secondary forests is perhaps the most important feature to take into account for management purposes (e.g. medicinal plants, edible fruits, firewood, wood for rural construction and handicrafts).
The silvicultural treatments used to stimulate production of commercial timber species in tropical primary forests, such as liberation thinning and refining, are also applicable in secondary forests. Young secondary forests appear to be more receptive to silvicultural manipulations because of the manageable tree size and anticipated growth response. This also applies to enrichment plantings, as the planted trees require canopy manipulation in order to optimise their growth and survival. Generally, experience with enrichment planting when applied in young secondary forests has been very promising.
When high timber productivity is a main objective, a monocyclic system that relies on creating a future, even-aged stand by opening the middle and upper canopy shortly before tree harvesting is perhaps the most amenable. This strategy is indicated for pioneer/light-demanding species that require almost complete canopy removal either for stimulating seed germination or for sustainable seedling growth and survival. In any case, the financial competitiveness with timber plantations has to be taken into account when this silvicultural management option is considered.
Shifting cultivation and grazing, although adapted to the physical environment of some African countries, are not sustainable under present conditions. Given the current rate of population growth and the demand for food, countries in the region should move away from extensive agricultural systems and adopt intensive and sustainable production practices such as agroforestry.
In addition, they should integrate agro-silvo-pastoral practices, which will enable each system to benefit from the other by, for example, integrating agroforestry practices with food crop and animal production. Governments could also encourage farmers and the private sector by financial or other incentives to process wastes and transform them into organic fertilizers that can be used to intensify agriculture. Such policies would foster higher land productivity, result in greater food security and improve health conditions and thus prevent secondary forest degradation.
The introduction of such policy packages should be backed by financial and technical resources. Currently, these are not readily available to some governments in the region. In spite of these obstacles, however, this policy package is politically feasible and, except in a few countries, the appropriate infrastructure exists to implement it.
The majority of people in Africa depend on the land and, more often than not, on the secondary forests for their livelihood, specifically through farming, animal husbandry, small-scale mining or collecting NTFPs. With the increasing cost of living in the region, coupled with the increasingly unsustainable nature of some of these activities, and in view of the need for food security and improved wellbeing of the population, alternative employment policies need to be developed and implemented.
These policies should provide for the needs of the increasing number of secondary and tertiary school-leavers, most of whom are unemployed. Alternative employment policies based on processing industries, trade and handicraft could ease pressure on the land and offer opportunities to people to generate extra income. In particular, processing industries could concentrate on adding value to most of the NTFPs collected from the secondary forests.
For such policies to succeed, governments need to address the problem of the inadequate capacity of people to embark upon new ventures. Concerned populations must be assisted, through training and the provision of micro-capital, to adapt to new opportunities. For example, the well-known entrepreneurial capacity of women in West Africa should be promoted (UNEP, 2000).
There is also a lack of adequate data, knowledge and expertise on the ecological, silvicultural, socio-economic and institutional dimensions of secondary forests. This affects and influences people's perceptions of the resource, masks its importance and potential and often results in poor management, degradation and inappropriate conversion.
The value of secondary forests has not been documented and neither have the rights been formally recognized of all those people who depend directly or indirectly on forest resources for their livelihoods. This results in inappropriate conversion of secondary forests.
Although secondary forests offer a variety of benefits and advantages over other land uses, they are often eliminated as quickly as they become established to make room for other land uses such as pastures and agricultural crops, or simply to "tidy up". If secondary forests are to be conserved and productively managed, the farmers or communities that manage them must receive a benefit that justifies that management and the benefit provided by the forest must be greater than alternative uses for the land resource where they are growing.
The perception, which is widespread among the concerned public and even among tropical foresters, is that unless the yield (volume) and net return (value) of secondary forests compare favourably with those of industrial plantations, they are not worth the investment. Such a view clearly ignores the potential benefits-to-cost ratio in the different management strategies in secondary forest management. It ignores the value of the diversity of such forests not found in industrial plantations. It sees labour-intensive, silvicultural interventions as a cost rather than a social asset. It also assesses the returns on the basis of wood alone. Even so, it is based only on producing a small fraction of forest products that have become marketable, and ignores the wide range of potential new products. It also ignores the service functions of secondary forests.
Many people living on the forest margins hold another perception. They value the secondary forests differently. The perception of these stakeholders might include non-monetary values (such as gathering forest products for immediate livelihood concerns, protection of the hydrological function in a catchment above their irrigated fields), spiritual, religious and other cultural values (such as aesthetics of forests to which they are accustomed, or which may attract future tourists) and non-perceived service values. Their readiness and availability to implement or support the management of secondary forests will only be assured if their perception is respected and strengthened.
In any case, all stakeholders should agree that management strategies applied in secondary forest management need to be cost-effective and economic.
Most African countries have not developed policies or legal and institutional frameworks that focus on the management of secondary forests. The development of these is a prerequisite to promoting sustainable management and use of secondary forests to prevent degradation and inappropriate conversion to other land uses.
There is the need to recognize secondary forests as a legitimate land use type endorsed by local land users. There is also the need to establish effective regulatory mechanisms by defining responsibilities for resource security, management and control of harvesting of products from restored and rehabilitated forests.
Policy decisions need to be based on a full cost-benefit assessment and identified transfer payment mechanisms for forest products and services. Inadequate assessment and sharing of costs and benefits related to the management and use of secondary forests may lead to inappropriate conversion.
Considerable information and knowledge are available on the management of secondary forest, but in many cases this information remains inaccessible for national forest services and other stakeholders. There is a need to clearly define units within national forest services that specialize in management of secondary forests. These units should become centres of excellence that coordinate activities with all concerned stakeholders in an open and transparent way to facilitate cooperation.
Secondary forests need to be seen as an integral part of the rural tropical landscape. They are affected by off-site conditions, particularly land use. Within any given landscape, some secondary forests may need to be converted to other uses, but such conversion should be part of an overall land use plan that optimises the allocation of land within the landscape.
Smallholders constitute the majority of land users in Africa, but traditional land laws recognize the land resource as a communal property. Thus, most secondary forests are recognized as communal property. Both smallholders and traditional land laws need to be considered in the management of incentives for better management of secondary forests.
Reform of land tenure systems is needed, but it must be based on a refined understanding of the socio-cultural conditions and local politics of individual countries. An improved land tenure system would bring about land security and could encourage investment in secondary forests, promote higher land productivity and reduce the rate of secondary forest degradation. Most governments in the region have not had the political will to introduce land reform policies because of the politics of ethnicity and the complicated nature and sensitivity of land reform; this could lead to social upheaval and even civil war. However, such policies are necessary and timely, but will only be successful with a participatory approach to land tenure reform.
Effective and suitable forest governance, as well as governance in general, is a necessary framework condition for a meaningful commitment to the management of secondary forests. The implementation of effective forest governance systems will address the framework conditions for the sustainable management of forests as a whole. This implies that national policies and legal aspects, appropriate economic governance and incentives and an appropriate institutional framework should be in place.
The quality of decisions made on the fate of degraded primary forests and secondary forests will be improved as the quality of information about these forests and their social, economic and ecological context improves. There is thus the need to promote applied research and create knowledge based on all aspects of secondary forest management. There is also a need to develop awareness regarding the characteristics, importance and management options for secondary forests at local, national and international levels.
In the final analysis, all the reforms needed in the region depend on political will. They also require a coherent legal and institutional framework, which will establish the rules for economic activity and political participation and underpin social coherence. Economic liberalization and good governance will create an enabling environment for popular participation in the decision-making process.
The following actions should be undertaken to facilitate the sustainable management of secondary forests.
Secondary forests are currently an integral part of the landscape in tropical Africa and therefore their sustainable management is very important, not only to provide environmental services and sustainable livelihoods but also to save the remaining primary forests. Therefore, all national governments and other stakeholders should make all decisions and actions to promote this now. There is no further time to lose.
1. Biodiversity Support Program 1993. African Forest Biodiversity: Foundation for the Future. A Framework for Integrating Biodiversity Conservation and Sustainable Development, USAID.
2. Blaser, J. & Sabogal, C. 2002. Management strategies for degraded landscapes. Draft guidelines for the restoration of degraded primary forests, the management of secondary forests and the rehabilitation of degraded forest land in tropical regions. Draft report prepared on behalf of ITTO as basis for deliberations of the Expert Panel. Bern, Switzerland.
3. Budowski, G. 1970. The distinction between old secondary and climax species in tropical Central America old forests. Tropical Ecology 11, 44-8
4. Chokkalingam, U. & De Jong, W. 2001 Secondary forest: a working definition and typology. International Forestry Review 3:19-26
5. FAO 1995. Forest Resources Assessment, 1990: Global Synthesis, Report No. 125, FAO, Rome.
6. FAO 2001. State of the World's Forests. FAO, Rome.
7. Guariguata, M.R. & Finegan, B. 1997. Ecology and Management of Tropical Secondary Forests: Science, People and Policy. Proceedings of a conference held at CATIE, Costa Rica, November 10 -12, CATIE/ CIFOR. In Proceedings of the Conference on Ecology and Management of Tropical Secondary Forest: Science, People, and Policy. (Turrialba, Costa Rica 10-12 Nov 1997).
8. Richards, P.W. 1966. The tropical rain forest. Second edition. Cambridge University Press.
9. Riuz Perez, M. & Arnold, J.E.M. 1995. Current issues in non-timber forest products research. CIFOR and ODA.
10. Smith, J. & Scheer, S. 2002. Forest carbon and local livelihoods. CIFOR.
11. Swaine, M.D. & Hall, J.B. 1983. Early succession in cleared forest land in Ghana Journal of Ecology 71, 601-27.
12. UNEP 2000. Alternative Policy Study: West and Central Africa. Technical & Regional reports GEO-2000 Report
Country/area |
Total forest 2000 (`000 ha) |
Forest
plantations |
Natural
forest |
Secondary forests estimated to be between 40% of natural forests |
Benin |
2,650 |
112 |
2,538 |
1015.2 |
Burundi |
94 |
73 |
21 |
8.4 |
Cameroon |
23,858 |
80 |
23,778 |
9511.2 |
Central African Republic |
22,907 |
4 |
22,903 |
9161.2 |
Comoros |
8 |
2 |
6 |
2.4 |
Congo |
22,060 |
83 |
21,977 |
8790.8 |
Côte d'Ivoire |
7,117 |
184 |
6,933 |
2773.2 |
Dem. Rep. of the Congo |
135,207 |
97 |
135,110 |
54044 |
Equatorial Guinea |
1,752 |
1,752 |
700.8 | |
Gabon |
21,826 |
36 |
21,790 |
8716 |
Ghana |
6,335 |
76 |
6,259 |
2503.6 |
Guinea |
6,929 |
25 |
6,904 |
2761.6 |
Guinea-Bissau |
2,187 |
2 |
2,158 |
874 |
Liberia |
3,481 |
119 |
3,362 |
1344.8 |
Madagascar |
11,727 |
350 |
11,377 |
4550.8 |
Nigeria |
13,517 |
693 |
12,824 |
5129.6 |
Rwanda |
307 |
261 |
46 |
18.4 |
Sierra Leone |
1,055 |
1,055 |
422 | |
Togo |
510 |
38 |
472 |
188.8 |
Uganda |
4,190 |
43 |
4,147 |
1658.8 |
United Republic of Tanzania |
38,811 |
135 |
38,076 |
15470.4 |
Total |
326,528 |
2,413 |
324,115 |
128436 |
Species |
Uses |
Alchornea carchifoli |
Abortion; appetizer |
Allophylus africanus |
Fuelwood; anthelmintic |
Alstonia boonei |
Adulterants; birdlime building accessories and furnishing |
Anthocleista djalonensis |
Lactogenic |
Anthocleita nobilis |
Potions and medicine; anthelmintic |
Antidesma membranaceum |
Abortion |
Baphia pubescens |
Ribs for umbrellas |
Bersama abyysimia |
Anthelmintic; lower back pains |
Bertiera racemosa |
Dentition; antidote to snake venom |
Bombax buonopozense |
Leaf vegetables; sweets and beverages |
Bridelia atroviridis |
Diuretic; purgative |
Bridelia grandis |
Lactogenic |
Caloncoba gilgiana |
Used for permanent structures and building materials; wild fruits |
Caseria bartii |
Chewing stick |
Ceiba pentandra |
Spinach; resin; source of honey; soap making |
Celtis adofi-friderici |
Timber; building materials; trunks and coachwork |
Celtis africana |
Fodder; tools and crafts |
Chaetacme aristata |
Fuelwood; cold relief; purgative |
Cleistopholis patens |
Source of drinking water; spinach; anthelmintic; fever remedy |
Cola caricifllia |
Industrial or cash crops; bows; eye diseases |
Cola digtata |
Permanent structure materials, e.g. mud houses |
Cordia millenil |
Roofing materials; furnishing and drums |
Cordia platythyrsa |
Drums; stools; canoes; musical instruments |
Cordia senegalensis |
Backache |
Cordia vignel |
Purgative; minematism |
Croton penduliflorus |
Fever remedy |
Daniella orgea |
Gum; veneers; plywood |
Daniella thurifera |
Coagulants; resin; furniture; joinery |
Diospyros abyssinica |
Mortar; permanent structure and building materials |
Discoglyprema caloneura |
Dolls; marks |
Dracaena arborea |
Soap making; hedges and decorative purposes |
Ehretia cymosa |
Chewing stick; fever remedy; laxative; tetanus |
Ehretia trachyphylla |
Tool handles |
Elaeis guineensis |
Wine; salt substitute; difficulty in childbirth |
Erythrina addisoniae |
Tannin |
Erythrina mildbraedii |
Prevention of toothache; mordant; soap making |
Erythroxylum manii |
Furniture; soap making |
Ficus sur |
Mortar; wild fruits for animals; fodder; aphrodisiac |
Ficus exasprata |
Anthelmintic; curing of disorders; eye diseases |
Ficus mucosa |
Salt substitute |
Grewia mollis |
Healing of wounds and cuts; fibre plants; salt substitute |
Hannoa klaineena |
Building of planks; fever remedy; for gripping belly pain |
Hanngana madagasccoiensis |
Building materials, especially windows, frames, wooden rafters |
Holarrhena floribunda |
Adulterants; stools; can serve as a decorative tree |
Holoptela grandis |
Timber; building materials; construction; expulsion of worms |
Lannea welwitschii |
Fodder; jams and fruit tarts; dyes and fuelwood |
Lophira alata |
Timber; green manure and panelling |
Marcaranga bartei |
Treatment of venereal diseases |
Macaranga heterophylla |
Treatment of venereal diseases; salt substitute; antidote to snake venom |
Macarangi hurifolia |
Purgative |
Maepris emini |
Edible oils; furniture |
Malacantha alnifolia |
Construction; eye diseases |
Margaritaria discoides |
Tannins; chewing stick; aphrodisiac treatment |
Markhamia lutea |
Paddles for canoes; chewing stick; tannins |
Markhemia tomentosa |
Tannin production |
Timber; adulterants; treatment of vulnerable disease | |
Millettia zechiana |
Bronchial troubles |
Morinda lucida |
Permanent structures; pit-props; amenorrhoea |
Morus mesozygia |
Timber; pestles; shade trees |
Musanga cecropoides |
Fodder; source of drinking water; manure |
Nauclea diderrichii |
Timber; wooden house and construction of piles in harbour |
Newbonldia laevis |
Bridge construction; fuelwood |
Petersianthus macrocarpus |
Construction of railway sleepers and vehicles |
Premna angolensis |
Fever remedy |
Psydrax parviflora |
Insecticide |
Psydrax subcordata |
Mental troubles; fuelwood |
Pteleopsis hylodendrom |
Basket weaving |
Rauvolfia vomitoria |
Fibre plants for decorative purposes; curing of jaundice |
Rhodognaphalon brevicuspe |
Treatment of boils, diarrhoea, fractures |
Ricinodendron heudelotii |
Salt substitute; green manure; soap making |
Sapium ellipticum |
Mortars; purgative; poison |
Solanum eriantham |
Shrubs; expulsion of worms |
Spathodea campanulata |
Appetizer; avenue trees; curing of ulcers |
Sterculia tregacantha |
Fibre plants; fuelwood |
Stereospermum acuminetissimum |
For styptic, for decorative purposes and for healing wounds |
Terminalia ivorensis |
Timber; dyes; truck and coachworks |
Terminalia superba |
Timber; aircraft propellers and stools |
Tetrapleura tetraptera |
Emetic; construction of horse-drawn carts; resin; fever remedy |
Tetrorchidium didymostem |
Chewing stick; seponin-producing plants; fever remedy |
Trema orientalis |
Fibre plant; charcoal |
Triplochiton scleroxylon |
Timber; building construction; truck construction; temporal roofing |
Vernomia amgydalina |
Spinach; fuelwood; heart diseases; lactogenic |
Vernomia colurata |
Source of honey; spinach; for skin diseases and antidote to poison |
Veromia conferta |
Antidote to poison; salt substitute; purgative |
Xylopia aethiopica |
Bows; construction of canoes |
Vocarga africana |
Fibre; birdlime; salt substitute |
Zanthoxylum gilletii |
Fuelwood; drums; curing cancer |
Zenthoxylum leprieurii |
Aphrodisiac; drums; treatment of hernia and rheumatism |
