Utilization of non-timber tree products in dryland areas: examples from southern and eastern Africa
The livelihood of the majority of rural people in African drylands depends on the forests and woodlands as sources of agricultural land, firewood and charcoal, as well as non-timber tree products such as food, fibre and medicines. As the ecological balance in arid and semi-arid environments is delicate, sustainable land-use practices are required if people's basic needs for the future are to be fulfilled. Sustainable utilization of tree and shrub resources, as in agroforestry, is an integral part of this.
The main objectives of this paper are to emphasize the variety of non-timber tree and shrub products found in drylands, to describe their utilization and to indicate local people's knowledge.
Field research and observations took place in Kenya and Mozambique, where migration and changes in settlement have occurred in recent history. Such migration has brought together varied experiences, and it has also caused changes in traditional woodland utilization.
Field experience has been checked with other information from the drylands of southern and eastern Africa, so as to give a broader view of current woodland product resources and their potential in the region.
As examples of the utilization of non-timber tree products (NTTP) in dryland Africa, we present two case studies from different ecological zones: northern Mozambique, where higher rainfall induces subhumid conditions and miombo woodland vegetation, and northern Kenya, with arid conditions and sparse natural vegetation. Both examples are from regions where migration and settlement changes have taken place in recent history and have influenced land-use practices. The approach to developing agroforestry systems and integrating NTTP species differs between the two regions. In both sites indigenous plants are preferred. The question of testing suitable species for introduction is more relevant in the case of Kenya, while in Mozambique, an inventory of locally existing plants and products has first priority.
Field work was undertaken between 1989 and 1995 in the province of Cabo Delgado, located in the northeast of the country, in collaboration with the `Projecto Piloto de Reflorestamento de Cabo Delgado' (PPR, Cabo Delgado Pilot Afforestation Project), a project of the Mozambican Ministry of Agriculture, supported by the African groups of the Swedish Recruitment Organization (ARO).
The area represents littoral plains, a plateau up to 850 m in the north, and varied landscape with elevations of about 500 m in the central and southern zones. The soil types range from poor coastal dunes and lithic soils in the littoral to mostly ferralitic soils in the interior. The climate falls in the transition between tropical subhumid to semi-arid, with a mean annual precipitation between 800 mm at the coast and 1300 mm in the interior. The dry season from April-May to October-November lasts about seven months. The natural vegetation for the greater part is miombo woodland, characterized by Julbernardia-Brachystegia species. In the north, semi-deciduous forests occur, which include timber species such as Pterocarpus angolensis DC., Millettia stuhlmannii Taub., Afzelia quanzensis Welw. and Dalbergia melanoxylon Guill. & Perr. In the littoral savannas, Adansonia digitata L. predominates; while along the coast mangroves are important (Ministério da Educacão 1986, Millington & Townsend 1989, Chonguica et al. 1990).
Subsistence agriculture dominants the social economy, although some fisheries and a few extractive industries also occur. These activities have been adversely affected by civil war, land-use change and economic breakdown. After independence, the dispersed rural population was settled in communal villages, and cultivation changed from itinerant or semi-itinerant to more permanent practices. Migration and further population concentration during the civil war led to exhaustion of soils around villages. There has been some reversal of these trends since the end of the war.
In the smallholder farming systems, the main subsistence components of dryfarming crop production are cassava, maize, sorghum and groundnut with little or no cash crop production. Farmers cannot afford external inputs, and crop yields are low (SPPF 1990).
There is great potential for agroforestry systems and the production of NTTP in this area:
· There is a need for sustainable low-input production systems, as an alternative to current non-sustainable land-use practices.
· Agroforestry could provide opportunities for the rural population to improve their production of subsistence crops and to initiate cash-generating opportunities.
The `Projecto Piloto de Reflorestamento' (PPR) started in 1985 as an afforestation project with a research component, beginning with species trials (mostly exotic plantation species). Later its activities shifted to forest extension and should in the future include management of indigenous forests and woodlands, and especially woodland utilization by local people. As a consequence of this interest, a survey about the utilization of tree products (timber and non-timber) was conducted in nine districts of the province, in 1992/93. This was primarily intended to give indications for planning extension activities, rather than achieving scientific standards. A later study, in 1995, focused on one village in Pemba-Metuge District (50 km from the provincial capital), with special reference to village-level utilization and management of woodland resources.
The survey methods started with interviews based on questionnaires developed by technical staff, conducted by the extension workers stationed in the districts. The questions covered the utilization of tree products (timber and non-timber), preferred species for certain different uses, and the experience of local people with tree planting and cultivation. The information collected was not subjected to quantitative analysis because of variability in the types and numbers of people interviewed in each district.
In the field study, semi-structured and open interviews were made in the village, targeting individuals and groups. Visits were made to forest areas and farmers' fields for interviews with key informants from the rural extension service and forest service. In this instance, selection of interview partners focused on differentiation and contrast by gender, ethnic origin and settlement. Cross-checking and triangulation were applied whenever possible. Assistance from local extension staff was used for translation from Makua to Portuguese.
The identification of local tree species was done partly by collection and cross-referencing with botanical specimens and partly by matching vernacular tree names with unpublished botanical information from earlier studies (Silviconsult Ltd 1984). This approach does not represent a thorough ethnobotanic survey of the region.
About 150 local trees and shrubs for all utilization categories, timber and non-timber (including carpentry, firewood and charcoal), were recorded from the survey and the field study. This including some exotic, introduced species. About half of the species were identified by botanical names, while the remainder were identified only by their vernacular names, some of which could well have been synonyms for the same species or the name of a product of a given species.
Non-timber tree products recorded in the study included foods, medicines, fibres and dyes. Among the most frequently named species:
Foods. Sclerocarya birrea (A. Rich.) Hochst., Ziziphus mucronata Willd., Adansonia digitata L., Tamarindus indica L., Annona senegalensis Pers. (fruit or fruit pulp), Ricinidendron rautannenii Schinz (kernels) and Moringa oleifera Lam. (leaves). Other fruit species named include Ximenia sp. (X. caffra Sonder and X. americana L.), Flacourtia indica (N.L. Burm.) Merr., Pachystela brevipes (Baker) Engl., Vitex sp. (V. doniana Sweet and V. payos (Lour.) Merr.), Cordyla africana Lour., some of them being consumed mainly during times of food shortage. The total of about 20 species mentioned seems rather low and might be because of the low representation of women in the interview surveys.
Medicine. Sclerocarya birrea (A. Rich.) Hochst., Crossopterix febrifuga (Afzel. ex G. Don) Benth. (bark), Annona senegalensis Pers., Terminalia sericea Burch. ex DC., Dichrostachys cinarea (DC.) Wight & Arn., Afzelia quanzensis Welw. (root), Tamarindus indica L. (fruit), Moringa oleifera Lam., Adansonia digitata L. and Eucalyptus camaldulensis Dehnh. (leaves). The total number of species mentioned was about 40, all of them known to villagers, as no special information was obtained from traditional healers.
Bark fibres. Brachystegia boehmii Taub. and Sterculia africana (Lour.) Fiori (mainly in house construction), together with several unidentified species.
Dyes. Pterocarpus angolensis DC. (bark resin) and several unidentified species.
Utilization of most of these species has been described in literature for other regions of southern Africa (Carvalho 1968, Palmer & Pitman 1972, Jansen & Mendes 1984, FAO 1986, Booth & Wickens 1988, Palgrave 1992, Abbot 1993), including the use in folk medicine, although the application may differ from the one recorded in Cabo Delgado. Medicinally active substances are known to occur in different parts of Sclerocarya, Adansonia and Moringa (FAO 1986, Booth & Wickens 1988).
Most of the species mentioned are indigenous, with the exception of Moringa oleifera, an introduced species that has become very popular as a living fence for village and township homegardens, and Eucalyptus camaldulensis, which has been distributed by the PPR in recent years.
The present stages of NTTP species management observed in Cabo Delgado, summarized in table 1, show patterns similar to those described in other case studies from the southern African region (see Campbell et al. 1991, Packham 1993).
Table 1: Management of NTTP species in Cabo Delgado
|Woodlands||Opportunistic utilization||Natural-growth indigenous species|
|Fields||Selective conservation||Indigenous multipurpose species (Tamarindus indica, Sclerocarya birrea, Adansonia digitata, Ziziphus mucronata) and planted domesticated fruit trees (mango, cashew)|
|Homegardens||Planting||Few indigenous fruit species (Sclerocarya birrea, Ziziphyus micronata), introduced species (Moringa oleifera, Eucalyptus camaldulensis) and domesticated fruit trees (mango, guava, coconut, citrus)|
Different tenure regimes regulate access to products. In natural woodlands almost anybody has open access to trees and their products. However, planted trees in a homegarden are private property, and the owner executes full control over the products. The situation regarding natural trees left standing in fields is less certain. Although the cultivator may be considered the owner of the tree, access to some of its products, like fruit, can still be open.
Selective retention of trees seems to be motivated by a combination of expected benefits from a tree, including non-timber and timber products, as well as shade. Tamarindus indica and Sclerocarya birrea are much valued, both for their fruits and for their timber, which is used to make utensils like mortars. Ziziphus mucronata poles are used for construction in the coastal area, and Adansonia digitata is not usually cut because of its spiritual significance.
Most products are processed and consumed within the household. The above-mentioned tree fruits are either consumed fresh or used in food preparation. The utilization of medicinal products is mostly the domain of traditional healers, whom people still actively frequent for treatment .
Commercialization of NTTP in Cabo Delgado is at present limited to the occasional sale of tree fruits (e.g., Adansonia digitata, Ziziphus mucronata, Tamarindus indica) in local markets or from street stalls. Bark and other fibres, along with poles and bamboo, are used in house construction in the vicinity of the provincial capital. Traditional house construction requires forest material and continues in villages as well as around Pemba township. Of all tree products, construction material and fuel (firewood and charcoal) have become the most important sources of cash income for rural households in this area.
Theoretically, several of the local NTTP species recorded in Cabo Delgado represent material suitable for domestication and commercialization. Some of them have far greater potential than their present level of exploitation in the province, compared with experience from other countries (FAO 1983, Booth & Wickens 1988). Moringa oleifera, for example, is a multipurpose species that has a variety of possible uses, in addition to using the leaves for food and medicine.
Packham (1993) states that `planting a species would appear to be a "step on" from preserving a species, and would coincide with high population pressure and a highly preferred tree'. This situation is still rarely found in Cabo Delgado, and thus the planting of indigenous species has been limited to highly valued species like Sclerocarya birrea. Without any information of future marketing prospects for non-timber products like indigenous fruits, people cannot safely be recommended to intensify their domestication efforts.
For many products, it can be expected that gathering from the wild will remain an adequate form of management, as long as the products can still be found in abundance. In many areas of Cabo Delgado this is still the case, but woodlands are under increasing pressure, mainly because of the search for fertile land for cultivation and the exploitation of trees for timber and fuel products. Sustainable woodland management, with active participation of the local communities, therefore, is needed to sustain the resource base for all forest products.
A silvicultural consultation was done in March-April 1993 in the Chalbi Desert in the northwestern part of Kenya, east of Lake Turkana. This area of Chalbi is characterized by special biophysical and social conditions, which make it an interesting case study for NTTP utilization.
Ecologically, the study area was situated in the northern part of the Chalbi Desert, which has erratic annual rainfall, averaging about 110 mm. The soils are calcareous, salty and alkaline (pH ~ 9,0), which cause a poor physical structure. The groundwater level is at 4 m only, and the water is brackish. Water samples analysed by the National Agriculture Laboratories, Nairobi, was very high in salinity. A steady wind dries up the soil and the plants very rapidly, so that vast areas are devoid of vegetation.
Apart from famine relief, the availability of resources that support life, such as water and forage for livestock, is highly variable in time and space. So mobility and social cooperation are essential for survival in the Chalbi Desert. A common strategy among the Turkana people living in these drylands of northern Kenya,is the redistribution of surpluses of food and wealth (Morgan 1981).
In the Chalbi Desert, however, the social conditions and relationships are different. Originally it was an area of the Samburu and Rendille tribes (Becker 1984), but there is now a neighbourhood of sedentary and nomadic people in and around North Horr town. They come mainly from Borana and Gabbra areas, bordering Ethiopia. Many of them are refugees, who also come from Somalia and Sudan. Additionally, there are external influences from an Islamic and a Catholic centre, and also the mission hospital, all of which have brought in new values
Some own goats, sheep and camels, but for long periods many of the people have to rely on famine relief. The concentration of people in the feeding camp has taken them out of their pastoral lifestyle. Even a low population of stock in this environment results in serious localized depletion of the vegetation. The restricted range of movement by these now-sedentary herds strains the vegetation resource further (see also Broch-Due & Storas 1981, Barrow 1988). Consequently, environmental degradation is serious and related to the social, policy and tenure issues of the area.
A tree planting project, `Durte Farm', was initiated at the end of the 1980s by Mr. R. Haller from Baobab Farm Ltd., Mombasa ,and assisted by Mrs. M. Dunkel, an agriculturist, on the grounds of the Catholic mission in North Horr and at some other spots and water points in the Chalbi area. The aim of the project was to sensitize people from the feeding camps to the value of vegetation and to motivate them to plant and take care of trees. More than 40 tree species from different origins were planted by Mrs. Dunkel and her assistants. The preferred species were those providing non-timber tree products. Seedlings and cuttings were produced under shade in the project nursery at the mission in various mixtures of fertilized soils and sand with different irrigation schemes. Survival will depend upon the root system finding the groundwater table. Although the revegetation approach seems artificial, the intention is to foster soil improvement and a better microclimate, so that natural regeneration will subsequently take place.
Barrow (1991) emphasized that in many drylands `it makes good sense to lay emphasis on sustained conservation and utilization of the natural resources, as opposed to tree planting exercises, through conservation and management of existing trees; natural regeneration of trees; and building on existing viable and valuable natural resources management strategies'. Barrow (1988) also recommended that the `tree species to plant should be based on what people want to plant, after all it is they who will be using and managing the trees. New species can be introduced but this should be done initially on a demonstration basis.' So in Barrow's sense, `Durte Farm' has to be regarded as a demonstration of new species that may be introduced, and of the methods to re-establish those species that have already disappeared from the Chalbi Desert.
Without the idea of commercializing NTTPs, an inventory was carried out in 1993 of the species that showed drought tolerance, deep rooting and tolerance to high salt concentrations and alkalinity. Those species with useful NTTP were emphasized. These products act as an incentive for people to plant them.
In addition to Haller's proven method of trying out seeds from many different species from comparable climates, we also searched the literature for well-adapted species (Dale & Greenway 1961, Palmer & Pitman 1972, Palgrave 1977, Becker 1984, Rocheleau et al. 1988, Friis 1992, Weiss 1993). Names and information about the trees were also cross-checked with this literature.
During the inventory, community members of different origins, social and ethnic backgrounds and age groups were interviewed in an unstructured manner and observed concerning their use of trees and shrubs. Collecting information about the medical use of plants was not an objective, because of the proximity of the mission hospital and the low expectation of making close contact with traditional healers within the short period of the survey.
We had to carry out interviews very carefully because of the extremely difficult social situation in North Horr. Those interviewed during the survey included men and women; older people and children. The interviews were focused on the people in the feeding camp, who were influenced by the nomads, and some of whom had a nomadic background. Nomads outside the camp were not interviewed. The questions were related mainly to the area close to North Horr (i.e., within a distance of a one-day walk) and the existing tree vegetation and not on the trees people knew from other areas. In cooperation with the `gardeners' of the Durte Farm, we also collected local information about specific trees in people's homesteads. Although many of these plants were still too young to bear fruits, information was collected in this way about the natural vegetation.
Lack of time, money and infrastructure prevented full rapid rural appraisal (RRA) (McCracken et al. 1988), farming systems research (FSR) or ICRAF's `diagnosis & design' techniques, but we did use elements of them. Our group was too small to be called an interdisciplinary team, and we did not have enough time for `triangulation' in every case. This survey was limited by the short time available for the study and the dependence of the expatriate researcher on assistance from mission personnel in arranging visits and interviews, and for translation from local languages to Kiswahili and English. For this reason the survey can be regarded only as a preliminary study requiring further in-depth investigation in the future.
The utilization of NTTPs in North Horr is far below the level of subsistence farmers, because of the change of lifestyle, the overpopulation and, especially the young age of the plants. Although there are frequent reports about the rapid decline in the vegetation caused by the increase in human population and new values brought in by migrants and refugees (Campbell 1986, Brokensha & Riley 1986), a wide theoretical knowledge about the potential utilization possibilities of trees and their NTTP was found. This is encouraging even if answers have been influenced by the interrogations of the observer. But, compared with our experience in Mozambique, there are very few hints for active use or passive knowledge about NTTP.
As foreseen, more indigenous than introduced species were named. We found children using NTTPs as `snacks' (mainly fruits but sometimes leaves); for example, newly planted Prosopis juliflora (Swartz) DC. pods and Moringa oleifera Lam. leaves were collected. Similarly, leaves of fruits of Balanites aegyptiaca (L.) Del., Boscia coriacae PAX. Cordia ovalis R. Br. ex A.DC., Hyphaene coriacae Gaertn., Salvadora persica L. and Ziziphus mauritiana Lam. (fruits and leaves) were eaten from natural vegetation. Interestingly, another snack children from all origins liked very much was the sweetened and coloured seeds and pulp from Adansonia digitata, packed in plastic tubes and imported from Mombasa. These were available in the North Horr shops.
Balanites aegyptiaca fruits were eaten raw, as in Ferlo, Senegal, despite the information that in Turkana fruits have to be boiled before consumed (Becker 1984). This was the case in our experience with the fruits of Dobera glabra (Forsk) R. Br. Furthermore, a few women cook milk with the pulp of Hyphaene fruits. So this fruit is also one of very few plant parts gathered in large quantities (see also Little et al. 1984). A systematic gathering of food plants for storage or further preparation was the exception, but it did occur. We found the use of ashes leaves and twigs of Atriplex canescens L., Salsola dendroides Pallas and Sueda monoica Forsk. Ex. J.F. Gmel. used as salt. Various plant parts from Salvadora persica L. were also used as a toothbrush.
The above-mentioned plants include the five that are the most important (Hyphaene, Cordia, Salvadora, Boscia, Dobera) in the diet of the Turkana (Becker 1984). Except Hyphaene and Cordia sinensis, three of the five most important plants in the Samburu diet, Grewia tenax, G. villosa and Cyphostemma maranguensi,s were not mentioned in the North Horr interviews. These plants are either absent or not yet old enough, following replanting in the Chalbi Desert. Very many plants were used as browse and collected for firewood. For browsing, donkeys seemed to prefer pods from Prosopis juliflora, Acacia tortilis Hayne and Acacia alba Del. Construction and fencing material was taken mainly from Hyphaena coriacea (see also Barrow 1988), Acacia reficiens Wawra Peyr. ssp. and Acacia brevispica Harms. (branches), but there was very little choice from other large-sized trees. Hyphaene branches and leaves were used for basketry and mat making. Medical uses were not as often reported as expected from literature (e.g. Kokwaro 1976, Ostberg 1988).
Food, except the Life Aid supplies, is in chronic shortage in this region. NTTPs could supply food during famines and food shortages, as reported by Falconer (1990). There are some indications that refugees in the North Horr camps know about trees and their NTTP values, but they do not make much use of them. Tree planting is not perceived as important work, as people are not permanently resident there. Consequently, the planting and irrigating of trees has to be initiated by `Food for Work' projects.
We agree with Barrow (1988), who emphasizes the importance of any arid-lands tree-planting project to make the connection between what the community knows (i.e., value of the trees) and what it does not know (i.e., the importance of tree planting).
The description of environmental and socioeconomic factors of both study regions indicates the need for development of balanced land-use systems in which tree species with useful non-timber products can contribute to food security and economic development of rural people. The two presented studies were conceived in a practical rather than a scientific context and were constrained by limited resources; they have been preliminary assessments of existing local knowledge and the state of exploitation of these resources. As such, they show the variety of NTTP utilization according to the resource base available (the relative richness of species of the miombo woodlands compared with that of the Chalbi Desert), and to social conditions, including the provision of food and medical aid.
The following recommendations for a development strategy to improve local livelihoods at both sites can be made:
· for Cabo Delgado. Build on the existing resources of indigenous and already introduced species by (1) the management of indigenous woodlands to sustain the resource base and (2) the further domestication of the most valued species already existing in farmers' fields and homegardens.
· for North Horr. The need is to improve the living conditions in and around the feeding camps by introducing NTTP species that could enrich the limited potential of natural vegetation. These would involve tree planting of new, introduced species or the reintroduction of indigenous species. Demonstration plots will be required to familiarize people with these species and their products. Conservation of the still-existing vegetation should also be promoted.
The research priorities for these regions are-
· completion of ethnobotanic inventories
· quantitative research on product use and availability
· a participatory assessment of the real needs of the rural people, with regard to subsistence and cash income opportunities
· an appraisal of land and tree tenure, because the availability of the product and its potential for contributing to improvement of people's living conditions depends on access to the resource base (common or open-access woodlands, individual fields, homegardens)
· an assessment of the possible influence (ecolgocal and socioeconomic) of introducing new and indigenous tree species
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