3.3 Desertification - Rethinking forestry strategy in Africa: Experience drawn from USAID activities

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T. RESCH (1)*


The problems of drought and desertification have achieved world-wide notoriety since the late 1960's/early 1970's when ecological disaster and famine gripped the arid and semi-arid areas of Sahelian Africa. This catastrophe was addressed first with humanitarian assistance and later with development programmes aimed at alleviating the causes of the problem. Despite concerted efforts over the last decade to turn the tide, another period of extreme drought is spreading havoc across the African landscape. The world is once again confronted with the tragic reality of the frailty and fragility of human existence in the arid and semi-arid regions of Africa.

It is therefore not surprising that the concern felt by African governments and their development assistance partners is prompting intense introspection. Past efforts are being reviewed and a better understanding of the problems and their solutions are actively being discussed. The present consultation convened by FAO is but one of these important encounters.

Forestry sector activities, often viewed as the spearhead in the fight against desertification, have expanded enormously in drought-prone Africa. In 1983, Weber (2) estimated that approximately 200 million U.S. dollars had been earmarked for forestry efforts in the eight countries of the CILSS alone (3). He was far less sanguine about the qualitative results of these endeavors. Despite the evident setbacks, not the least of which is the continued staggering loss of vital vegetative cover, important lessons have been learned about the role forestry can and should play in the development scenario of this region. These results must be shepherded, nurtured and carefully used in the design of future programmes. The purpose of this paper, therefore, is to describe the evolving role of forestry activities in light of this experience and its implications for the fight against drought and desertification.


Before proceeding further it is useful to review the difference between drought and desertification. The phenomena are, in the authors' opinion, frequently confused with evident impact on the effectiveness of the measures employed to counter them.

Drought is, in the main, a climatic event. While it is beyond the scope of this paper to examine in detail this complex subject, a few important notions are worth mentioning. The weather systems which underlie the extreme variability of the rainfall of arid and semi-arid Africa are thought to be the result of displacement of wind and precipitation patterns induced by other climatic circumstances which take place well beyond the affected areas (4). As yet there is little empirical data to link the occurrence of drought to human activities. Some authors have suggested, however, that to a certain extent drought through its effect on the vegetation and surface conditions in the affected areas feeds upon itself. Nicholson points out that this relationship has important meaning for land use in these areas as human activity itself in clearing the land may have the same effect (5). African and donor policy-makers must recognize the enormous potential for damage inherent in the systematic and well-intentioned conversion of natural vegetation to areas of marginally sustainable agriculture. It thus seems eminently sensible to adopt a "probable-case scenario" in designing interventions involving land-use practices in the region (6). Average rainfall is a deceptive indicator in assessing production potential for these areas, given the now well documented extreme variability of precipitation. Once cleared, it is an extremely costly and long-term endeavor to rehabilitate these lands, This should not be interpreted as a pessimistic call to simply control the expansion of the agricultural frontier. What is required are new methods of using these lands which sustain environmental stability. Much of what follow constitutes information on these new methods.

From another viewpoint, taking drought into consideration represents an exercise that demands special care in choosing alternative actions in the stricken areas. Confronted with the impact of drought, governments and donors alike have sometimes chosen large-scale, administratively unwieldy projectized responses. These projects, composed essentially of government "inputs" attempt to implant shallowly-conceived technocratic solutions to poorly understood problems. Besides the fact that they do not work, they also often degenerate into ineffective social welfare programmes which further undermine the community fabric on which solutions can and must be built. There is also a need for a sense of perspective which recognizes the long-term nature of the problem. Equally importantly, this perspective should focus on the "do-able" and achievable rather than the most challenging issues. It may mean, given the present drought, emphasis on maintaining viable farming systems and ways of life of the people on the vulnerable sedentary edge of the limits to cultivation whose land must often absorb the brunt of nomadic and refugee influxes.

Drought is unpredictable and recurring, and the famine that frequently accompanies it, even more so. As such it is a particular challenge to the preparedness of governments and donors alike to deliver humanitarian assistance in a timely and adequate fashion. Fortunately, climatic impact assessment technology growing out of the increasingly sophisticated and extensive applications of satellite-based remote sensing holds promise for the future. Through the use of these tools and techniques, early warning of potential drought induced food shortages, with lead times of 60-90 days, are now possible. This will enable more careful review of actual field conditions and preemptive mobilization for drought relief efforts. Obviously, as this technology develops, it is likely to greatly expand the available information so necessary for pertinent land-use planning in the arid and semi-arid areas of Africa.

Desertification is an even more serious problem than drought in that it represents a long-term, pervasive loss of productivity in a world whose escalating populations can scarce afford to lose it. Drought often exacerbates the impact of desertification but it is principally a result of man's inadequate stewardship for the land driven by these exponential demographic pressures. Desertification is the major environmental problem afflicting Africa today. It is also an important constraint, if not the major one, impeding food self-sufficiency over vast areas of the continent.

Desertification refers to the loss of the land's productive capacity - a change to desert-like conditions. More specifically this may involve the following negative results:

In the final analysis, the most important result of desertification is the misery and poverty of the people in the affected areas. These people often exist even in the better years with a tenuous hold on economic stability. Drought and its consequences can be remedied with short-term palliatives such as food aid and medical relief. Desertification may mean reconstructing a way of life.

In order to place forestry activities in proper perspective in combating desertification, it is necessary to review its causes. It is no doubt well understood that the principal cause of desertification is population pressure which induces increasingly intensified use of fragile resources leading to their degradation and destruction. Under such circumstances desertification can occur in better rainfall years as well as drought years.

Loss of vegetative cover - the trees, shrubs and herbaceous plant life removed from the land in converting it to other uses-exposes the surface to the unrelenting extremes of climate and breaks down the thin mantle of productive topsoil. Expansion and intensification of agriculture are the primary reasons for conversion. Much of the modest gain in agricultural productivity achieved in the Sahelian countries of West Africa has come from expansion of the agricultural frontier, often onto soils too marginal to sustain production for more than a few years without fairly intense soil conservation measures and fertilization (7). This expansion is particularly problematic when it takes place on sloping lands whose rapid degradation then cancels the important watershed effect they exercised in recharging groundwater. Even on better soils, intensification of use includes increased crop monocultures, choice of soil exhausting crops, inappropriate mechanization, disregard for soil conservation needs and shortened fallow periods. Uncontrolled burning, common in the semi-arid areas, also adds immeasureably to the problem. Over-grazing has long been associated with desertification resulting in elimination of palatable annual forage species, destruction of cover and soil compaction. Fuelwood and charcoal harvesting, to supply domestic energy needs (often for more than 85% of the population) has also contributed substantially to long-term resource degradation.

These causes, seemingly irrational behavior for the subsistence farmer, must also be viewed in the context of the social economic and institutional factors which mitigate against sustainable use and resource conservation. These include: land and tree tenure issues; lack of access to agricultural production inputs and credit; limited rural development initiatives; conflict within the communities and with local authorities (e.g. with the forest service); changing political systems; restricted market outlets; lack of off-farm income opportunities; risk perception by rural people (e.g., keeping large herds); and lack of social guarantees, to mention but a few.

Past Forestry Activities

Laudable efforts to contain the pace of deforestation and desertification have been launched throughout Africa since the great Sahelian drought. These endeavors represented increasing understanding of the importance of trees for environmental stability in arid and semi-arid Africa. Unfortunately, cause and effect vis-à-vis desertification has been too closely ascribed in the past to the "fuelwood problem". With escalating fuelwood demand, driven by population increases and readily quantified in astronomical terms, it is not surprising that the first programmes set ambitious production targets for reforestation.

Likewise, reforestation was seen as the task of the foresters and they were encouraged to take up the challenge with large influxes of donor support. Their early plans focussed on block plantations, their traditional forte, and occasionally on village woodlots aimed at involving the rural people. In the absence of sector models capable of analyzing priorities in the context of overall development issues, these first initiatives were readily accepted and their highly visible impact (plantations) judged appropriate. It was not until the late 1970's/early 1980's, as projects came under scrutiny as part of routine evaluation, that the lessons started to emerge. Reviewing ongoing projects in light of their efficiency and effectiveness led both Africans and donors to begin to question the strategy options which had been chosen (8). Capital-intensive block plantations for fuelwood production in arid and semi-arid areas have been crippled by the stifling combination of high costs, slow growth and low market prices. For the time being, such plantations are regarded as being not feasible in areas with less than 800 mm annual rainfall. Village woodlots relying on shared work for shared benefits on common land have proved an elusive goal for many reasons. In areas where trees are needed, by definition there is usually not enough real common land to achieve adequate impact.

The reality, as seen above in the discussion on causes is that the fuelwood model accounts imperfectly for the disappearance of trees in the desertification equation. In areas undergoing desertification, many components of the rural production system are in stress. Even the limited experience to-date has shown that rural people have seldom been enthusiastic about planting trees specifically and uniquely to produce fuelwood. This narrowly-defined objective has tended to be rather self-limiting and has understated the real value of trees to rural people (9). An exclusively "fuelwood approach" actually exacerbates the dichotomy between agriculture and forestry by reinforcing the ill-conceived notion that somehow the foresters alone are going to resolve the fuelwood/environment problem (10).

Trees and Agriculture in Subsaharan Africa

Renewed interest in forestry activities on a large scale by international donors grew out of the concerns for fuelwood supply ("poor man's energy crisis") and the environment. The early emphasis was useful essentially because it prompted action, although in part this rather narrow view of the problem contributed to the approach featuring block plantations. The needs for and the role of forestry in Subsaharan Africa, however, now appear quite different.

The major development issue in Subsaharan Africa today is the declining capability to produce the food necessary to feed the burgeoning population. An important dimension of this situation is the continued soil degradation resulting from intensified cultivation, continued clearing of marginal lands and the overall diminution of environmental stability leading to desertification. Forestry sector development specialists and others are coming to understand that rarely can projects and activities whose sole purpose is fuelwood production be sustained particularly in the arid and semi-arid areas of the region. Rather, these activities must be dual in nature, both production and protection-oriented, exploiting on a large scale the ameliorating soil and water conservation effects of vegetative cover in sustaining and promoting environmental stability.

Simply translated that means working with farmers to promote tree planting at least cost and with greatest scale and spread, namely on the farms and farming lands of Africa. In the harsh climatic extremes of arid Africa, agricultural development efforts must do more than simply strive to increase area yields of basic food crops through the introduction of modern technology. Attention must also be devoted to building on peasant subsistence farming systems in order to increase their resilience during poor rainfall years. Similarly, it seems evident that good fertile soils will be necessary to exploit the full potential of the increased supply of genetically enhanced varieties of food crops. It will likely require more than improved seeds to start the green revolution where it is most needed in Africa.

African agriculture is hostage to four major constraints which trees can help ameliorate. These circumstances are part of the desertification problem but also come into play on lands that for the moment are more or less intact. Rainfall is highly variable and growing seasons can be as short as two months.

Frequently large portions, as much as 40 to 60% of what rainfall does occur, are lost to runoff because of inadequate infiltration (11). Topsoils are unstable and subject to erosion from rain and wind. Several studies report losses from runoff of 20 to 170 tons of soil per hectare per year (12). In the summer of 1969 alone, 60 million tons of fine soil was blown from the Sahara and the Sahel to the Atlantic, carried by seasonal easterly winds (13). Nutrients are scarce, especially nitrogen, phosphorus and potassium, the major ones. When nutrients are lost to harvesting, leaching and runoff, soil fertility rapidly declines as do food crop yields. If not replenished, all available nitrogen in a field can be depleted by annual harvests in four years. Natural restoration of fertility through fallow may take up to twenty years (14). Annual crops can take up half the readily available nitrogen in a single harvest (15). Organic matter is easily lost under high soil temperatures thereby undermining the cation exchange capacity and accelerating nutrient leaching. Finally, growing populations compete for static amounts of food, fodder, fiber and fuel. The area of land available to produce these commodities remains essentially the same although populations in Africa at current rates may double every twenty years.

In contrast to these substantial constraints, and somewhat overshadowed by the fuelwood/forestry approach, are the positive effects of trees and shrubs in supporting agriculture. Where trees and shrubs are present, either bordering, sheltering or scattered within fields and grazing lands, these effects can have substantial impact. These are documented below:

Trees and their roots can have a bunding effect and enhance soil porosity which increases infiltration of rain.

This improves the microclimate within fields. Wind erosion is slowed. Neem windbreaks in Niger slowed wind velocities within the cropped area between the trees by 45-80% (16).

Nitrogen is captured from the air, fixed in the soil, retrieved through roots, redeposited as leaf litter and twigs.

Enrichment of surface soil layers attributed to the presence of Acacia albida trees has been documented in several studies (17). Increases in total organic carbon (C) and total nitrogen (N) in the soil under the trees, as compared with field soil beyond the tree canopy, were:

Niger (1960) N: 231% C: 269%
Senegal (1969) N: 33% C: 40%
  (1965) N: 194% C: 192%
  (1966) N: 110% C: 91%
Sudan (1969) N: 600% C: 200%

Several of these studies also documented increased soil water holding capacity and cation exchange capacity. Increases in mineral constitutents (Ca, Mg, K and P) ranged from 20 to 100% (18).

In Nigeria, leucaena hedgerows, cropped with maize, were still producing, after six years, about 160 kg N/hectare/year from 5 tons/ha/year of leaf prunings applied as green mulch (19).

- Crop yields can be stabilized, and in some cases increased. A few research studies have reported the following:

Niger (1979):
Yields of millet between neem tree windbreaks seven years old were 1099 kg/ ha, compared with 854 kg/ha in the control plot, a net increase in 23% after subtracting the area under the trees where no millet grows (20).

Nigeria (1984):
Maize yields stabilized at about 2 tons/ha/year after continuous cultivation for six years, using green mulching with leucaena leaves at rate of 5 tons/ha/year. Yields in the control plot declined to 500 kg/ha during this period (21).

Senegal (1965):
Yields of millet under Acacia albida canopy were reported as equivalent to 1,688 kg/ha, compared with 660 kg/ha on land outside the canopy, an increase of 152% (22).

Yields of sorghum under Acacia albida canopy were reported as equivalent to 934 kg/ha,compared with 457 kg/ha on plots outside the canopy, an increase of 104% (23).

Burkina Faso (1963):
Yields of millet under Acacia albida canopy were reported as equivalent to 1 250 kg/ha, compared with 820 kg/ha in control plots outside the canopy, an increase of 50%.

- Food and Fodder Reserves are available between harvests and during drought. Trees usually survive periods of no rainfall, drawing on ground water stored beneath the soil. Taproots of many trees are 20 meters or more long.

In the Sahel, tree leaves, seeds and pods account for about 5% of livestock fodder needs during the rainy season and up to 45% toward the end of the dry season, averaging about a third of year-round forage supply.

In Malawi, leucaena is produced on small holdings, undersown with maize, the foliage used as fresh forage, or sun-air dried for winter supplement, or sold as a cash crop. In some areas leucaena provides about one-fifth of fodder needs.

In addition to fruit, the seeds, pods and leaves of many trees are regularly used as food supplements. In time of drought, they provide marginal supplies.

- Fuelwood. Farm trees can be a significant source of fuelwood.

As few as 50 trees, on a 2-hectare farm, occupying less than 5% of the arable land can supply half or more of a farm family's fuelwood needs, by regular pruning and selective cutting (27).

Implementing Greater Integration of Agriculture and Forestry

The role of trees and forests, at the macro-level for overall environmental stability and at the field level for their effect on field moisture, soil nutrient status, and crop yield, is probably the most tried and accessible technology available in Africa today to combat desertification.

Planting trees in farmers' fields, in agroforestry configurations or as small woodlots, fence-rows, around the homestead or wherever they may fit, as well as maintaining and managing forests and woodlands for sustained multiple-use can be the key to environmental stability in Africa. This, however, means more than having foresters espouse and promote agroforestry. It means in effect, a policy and programmes that recognize the importance of tree and forest cover for agricultural productivity and which translate into a meaningful administrative, legislative and institutional framework capable of promoting and delivering this approach to the farmers. It will necessarily be a long-term proposition; neither the foresters nor the agronomists are as yet ready for this marriage and many vested interests and institutional problems will have to be overcome along the way. The time to start, however, is now; the outcome should be a multidisciplinary extension approach which seeks to service the opportunities and needs of the peasants rather than three separate extension services (agriculture, livestock and forestry) which compete for the attention and resources of the farmers.

Farm forestry will also mean change that must start with the foresters themselves, their attitudes and the way they do things. The traditional emphasis on safeguarding the reserve forests has led to policies and actions geared to conservation and control. In order to appropriately and effectively service a nation's largest client group its peasants - these policies and actions must evolve to a development and service orientation. It will be, in some cases, difficult to overcome the antagonism between peasants and foresters; the former are unlikely to believe that the latter have suddenly and miraculously become their benefactors.

More work on basic studies and research to assemble and amplify the effect of what is already known about the benefits of tree planting on crop production from a farming systems viewpoint will be necessary. More importantly, however, will be continuing the policy review already under way in some African governments about the integration of agriculture and forestry, and extending it and accelerating it where possible. A dynamic, practical process of policy dialogue among government ministries concerned, and between African governments and their donor partners, is necessary to address the issues of policy reform and institutional changes required to proceed with a practical integration exercise.

An important policy benchmark along the way to greater integration of agriculture and forestry will be a resolution of problematic land and tree tenure issues. Too often farmers are dissuaded from planting trees on their land because of doubts, real or imagined, about their future rights to those trees.

Putting such farm forestry systems in place will require, eventually, a massive and effective agricultural/forestry extension services programme, able to demonstrate to the farmer that the production tradeoffs associated with tree planting, protection and maintainance will yield tangible positive benefits to the family. The key to the success of the farm forestry fuelwood development strategy will be the nature of this extension programme In the past there have been a series of misconceptions about extension which have undermined their effect. Extension needs to be understood for what it is - the outreach function of a programme or project which permits dialogue between the client and the service. The outreach approach which is necessary is based on the notion that the most important element of a people-oriented development strategy are the people themselves, their needs, aspirations and opportunities. The forestry extension message, as part of the overall agricultural/rural development extension strategy must shift the control and policing to a service and development orientation. Such changes must be initiated by the government services themselves but must be guided by patiently-acquired information about the people, their attitudes towards trees and forests, their present uses (demand) and future needs, and their farm production practices as well as social management arrangements. Such information will guide the necessary reorientation of policy, codes, rules, forestry programmes, projects, and management practices. It will also assist the extension staff in helping the people themselves devise local participatory management schemes necessary to control the management, production and protection of agreed natural resources development schemes.

Farm forestry in Africa combined with the economic opportunity of a cash market place for fuelwood holds bright promise for meaningful impact on both productive and protective initiatives required to contain desertification.

A Final Word

It should be emphasized that these actions are recommended as part of, rather than substitutes for, the wide range of essential soil and water conservation and crop improvement measures urgently needed to help increase food production in Africa. Expanded national efforts in soil conservation engineering (terracing, bunding and contour plowing, etc.), water runoff control (micro-catchments and water harvesting), no-tillage techniques and research to shorten crop cycles will all be needed if we are to build-in greater resilence against drought in African farming systems. These measures cannot overcome the consequences of excessive drought or high population pressure. However, if systematically pursued they can increase the area of sustainable agriculture and buy time for the full spectrum of longer-term economic development efforts needed for individual and national growth.


1. T.M. Catterson is Senior Forestry Advisor, and F.A. Gulick is Forestry Planning Consultant, Africa Bureau, Agency for International Development, Washington, D.C.; T. Resch is Africa Coordinator, Forestry Support Program, USDA - Forest Service, Washington, D.C.

2. Weber, F, Review of the CILSS Forestry Sector Program Analysis Papers, CILSS Forestry/Ecology Technical Meeting, Banjul, The Gambia, Oct. 1982, pp. 94.

3. CILSS: Permanent Interstate Committee for Drought Control in the Sahel: includes Chad, Cape Verde, Gambia, Burkina Faso, Senegal, Mali, Mauritania and Niger.

4. For an excellent discussion of the climatology of arid and semi-arid Africa, see: "The Climatology of Sub-Saharan Africa", by Sharon Nicholson - Appendix B in Environmental Changes in the West African Sahel, National Academy Press, Washington, D.C., 1983, pp. 71-92.

5. Ibid.

6. A detailed discussion of the subject may be found in: Desertification in the Sahelian and Sudanian Zones of West Africa, West Africa Projects Dept., World Bank, Washington, D.C., Report No. 5210, 2nd draft, Feb. 1985, pp. 60.

7. Food Problems and Prospects in Sub-Saharan Africa - The Decade of the 1980's by C. Christensen et al, Foreign Agricultural Research Report No. 166, USDA - Economic Research Service, Washington, D.C. 1981, pp. 293.

8. A detailed analysis of past strategy is beyond the purpose of this paper. A similar exercise was undertaken in the paper: AID Experience in the Forestry Sector in the Sahel - Opportunities for the Future by T.M. Catterson, prepared for the meeting sponsored by the CILSS/Club du Sahel - "Concerted Action in Developing the Ecology/Forestry Sector in the Sahel Countries", Paris, June 1984. pp. 29.

9. Tree Growing by Rural People FAO Forestry Paper N. 64, Rome, Feb. 1985, pp. 133.

10. Op Cit. Catterson.

11. Charreau, Claude, Soils of Tropical Dry and Dry-wet Climatic Areas of West Africa and their Use and Management, lectures at Dept. of Agronomy, Cornell University, 1974, Agronomy mimeo No. 74-26, pp. 200-203. See Table on p. 202., and Productivity of Sahelian Rangelands, Course Book, Volume I, Wageningen Agricultural University, The Netherlands, 1982, pp. 145.

12. Ibid.

13. Jensen, A. M., Shelter-belt Effects in Tropical and Temperate Zones, July 1983, IDRC-MR80e, Canada, 61 pp., p. 34.

14. Op. Cit., Productivity of Sahelian Rangelands.

15. Op. Cit., Productivity of Sahelian Rangelands, p. 115.

16. Els Bognetteau-Verlinden, Study of Impact of Windbreaks in Majjia Valley, Niger, February 1980, Agricultural University, Wageningen, The Netherlands, 77 pp. plus annexes. Hereafter cited as Majjia Valley.

17. Felker, Peter, State of the Art: Acacia albida, U. of California, Riverside, Calif., April 1978, (AID Grant Afr-C-1361) p. 87, summarizing original research prepared by Dugain (Niger, 1960); Charreau and Vidal (Senegal 1965); Dancette and Poulain (Senegal 1969); Jung (Senegal 1966); Radwinski and Wickens (Sudan 1969).

18. Op. Cit., Charreau, Op. Cit., p. 214.

19. Kang, B. T. and B. Duguma, Nitrogen Management in Alley Cropping Systems, paper presented at the International Symposium on Nitrogen Management in Farming Systems in the Tropics, IITA, Nigeria. 23-26 October 1984, p. 7.

20. Op. Cit. Els Bognetteau-Verlinder, pp. 66-69 and Appendix VI.

21. Op. Cit., Kang, B. T., p. 12.

22. Charreau, C and P. Vidal, Influence de l'Acacia albida del. sur le sol, nutrition minérale et rendements des mils pennisetum au Sénégal, in l'Agronomie Tropicale, 1965, pp. 601-626. Yields reported p. 616.

23. Dancette, C. and J. F. Poulain, Influence of Acacia albida on pedoclimatic factors and crop yields, in African Soils, (XIV, N. 1-2) 1969, pp. 143 - 183.

24. Direction des Eaux et Forêts, Republic of Upper Volta, Secteur de Restauration de Sols de Ouahigonya, 1965, pp. 36.

25. Agroforestry in the West African Sahel, Advisory Committee on the Sahel, BOSTID, National Research Council, 1983, citing H.N. LeHouerou, "The Range Lands of the Sahel", Jnl of Range Management, 33(1): pp. 41-46, 1980.

26. Savory R, J.A. Breen and C.I.A. Beale, "Leucaena as a Forage Crop on Small Farms in Malawi", in Browse in Africa, H.N. LeHouerou, ea., International Livestock Centre, Addis Ababa, Ethiopia, 1980., pp. 411 - 415.

27. Spears, J.S., Review of World Bank Financed Forestry Activity, FY 1983, IBRD, mimeo, pp. 37.

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