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Arid-zone forestry

Where there are no forests and everything depends on trees

B. Ben Salem

B. BEN SALEM is the officer dealing with arid-zone forestry in the FAO Forestry Department.

Both theory and practice show that in areas with a long dry season, even those which are nearly deserts, natural woody formations and perennial plants make the best use of the soil and climate. In addition to their capacity for self-protection and biological improvement of the environment, they also afford protection for more modest plants growing under their shelter. The supreme example of a plant which is both woody and perennial is the tree. Trees, so often relegated to the most mediocre soils or cultivated only as a subsidiary activity, have an essential. if not preponderant, function to perform in semi-arid and arid zones. They should provide the framework and even, in some cases, the very basis of the rural economy.

The arid lands in the warmer climates of the world are generally characterized by low and erratic precipitation, diurnal fluctuations in air and soil temperatures and low humidity, although dew may contribute substantially to available moisture in certain seasons. Winds may be strong, days very bright and sunny and extended periods of drought are unpredictable, but inevitable. This means that such lands have a low threshold of susceptibility to misuse. When basic thresholds of resource tolerance to human and animal pressure are exceeded, He result is either deterioration or destruction of the physical environment with proportionally adverse effects on the rural population.

The primary reason for the massive human tragedies that are so common in arid and semi-arid regions is essentially land misuse under the marginal and fluctuating climatic conditions particular to these areas. Successful rehabilitation and improvement of the land require elimination of abuses by man. The starting point for improvement of agricultural productivity in arid and semiarid zones should be integrated planning in which the real nature of the land and the real nature of the people who are a part of that land are taken into consideration.

One of the most common and unrecognized misuses of arid and semiarid ecosystems involves the cultivation of annual plants without conservation measures.

Annual plants degrade soil fertility and are marginal for two reasons. First, the position of their root systems in the upper layers of the soil exposes them to the risk of desiccation, and second, because of the unreliability of the climate it is impossible to respect their specific requirements which are sometimes very strict with regard to installation, growth and maturation. Moreover, owing to the unreliability of the climate and the very nature of annual plants, the soil remains without protection and becomes exhausted during both the growth of the plants and the dry season. When planted with annual crops, arid and semi-arid ecosystems that are inherently marginal pass quickly from a state of fragility to one of total exhaustion. In other words, they are not being used in the way they were meant to be used. Sedentary and stable forms of agriculture are simply not feasible with the introduction of exotic annuals.

With perennial plants the situation is immediately different. Their growth does not depend on rain starting within two weeks of a certain date. Moreover, they cover the soil better and last longer, a trait which represents a step forward in the stabilization of the communities and of the environment. Whether natural or introduced, perennial woody plants are more profitable than the annuals, since they can provide a whole range of products: fodder, wood, minor products, even food for people and animals. First in importance among the perennials are trees of all kinds-fruit trees, semi-forest and forest trees - which are able, owing to their diversity, to adapt themselves to varying requirements. If the conditions for their installation and management are met, these lefty, bushy plants can simultaneously produce fodder, food and energy, provide shelter, break the force of the wind and possess all the advantages of self-protection. Their roots help to deepen and improve the soil; the shade they provide facilitates ecosystem metabolism; and they afford to plants less endowed by nature some of the benefits of the protection which they themselves enjoy.

With these functions in view and considering how best to combine the various elements necessary for the development of a stabilized agricultural system in arid zones, trees come immediately to mind as being essential for guaranteeing this stability and ensuring the continuity of agricultural activity. Such activity can be divided into three groups, based on the different ecological conditions prevailing in arid zones:

· Extensive stock raising, of a nomadic type, based on the use by wildlife and domestic animals of vast stretches of desert ranges.

· Grazing and forestry activities in arid areas, concentrated on natural grazing land.

· Agri-silvi-pastoral activity in semiarid zones, combining arboriculture, crop growing, wood and animal production.

Farming in arid zones should be confined to areas where there are sufficient groundwater resources (springs, wells) or where it has been possible to concentrate surface waters by runoff. This also applies to trees, whether forest or fruit trees, because for trees the limiting factor is lack of water: either they produce a lot of wood and also consume a lot of water, or they consume little water but then also produce little wood. This either slows their growth or reduces them in number to a very few per hectare. Since the climax of arid zones is a shrub steppe, the possibilities for introducing trees of necessity are very limited. Rather than planting trees which grow upward, it would be better under these bioclimates to cover the soil widely with low vegetation to stop the sand being blown away, to avoid the formation of zones of accumulation through wind erosion, and to make the ground more rugged. A plant cover with the same characteristics as the original steppe should be reconstituted.

In semi-arid zones there are greater possibilities for crop growing and trees have an important role to play in stabilizing agriculture. For this they must either be permanently present or regenerate without interruption in the same area. In the first case, we would have permanent trees or shrubs either in rows or scattered about. Their role can be summarized as follows:

How have desert peoples, whom outsiders might consider c; primitives, come to terms with their environments? The answer is in the cohesive social systems of these groups which have enabled them to create and organize farming appropriate to their land and climate.

· Trees in rows protect crops against wind erosion and desiccation.

· Trees intermingled with crops protect the crops and reconstitute and enrich the soil.

· Thus improved, the cultivated zones lose their marginal character, rotation cropping becomes possible and a supply of fodder is ensured.

· The ideal combination of semi-forest trees bearing edible fruit, fodder trees and forest trees ensures not only a diversified and stable production, but also agricultural and biological balance.

In the second case, where trees are regenerated, they are grown during the fallow period as part of rotation cropping, in order to regenerate the soil and provide cattle with supplementary fodder.


The outline of an overall land-use management strategy thus begins to take shape. Shelterbelts of forest species would be reserved for the great plains, where division of the land into plots and the presence of active farming prevent the close juxtaposition of trees. The hillocky peneplains, hills and slopes would be protected by scattered vegetation and would, over most of their area, be converted into a network of plots to be cultivated under a system of rotation cropping based on the use of woody vegetation.

Land-use management plans and forest policies in arid and semi-arid countries to date have been designed for and implemented in well-defined, individual areas where the tendency of the forester was to protect and conserve the forest for its own sake rather than adapt it to the requirements of the rural people. This attitude may have been justified in the past but cannot be accepted today in view of the accelerated degradation of the soils, the marginalization of agriculture and the growth in population. The basic prerequisite for an improvement in rural life is stabilizing agriculture, and trees should not be confined to areas marked off as marginal. Forestry should be considered not as a residual form of land use but as an indispensable component in an overall land management plan. Its presence guarantees conservation of the environment, improved renewal of the natural resources and existence of the conditions necessary to enable rural people to live a satisfactory life.

This being agreed, the stabilization of agriculture then becomes the forester's main contribution, rather than trees, shrubs, erosion control or the production of fuelwood. The whole art of the forester, which is essentially an art of management, really consists of incorporating silviculture into management of the whole land area and encouraging the adaptations necessary to ensure a greater contribution to the stabilization of land use.

In most arid and semi-arid countries the problem of land. management and the incorporation of trees is affected by the existence of traditional social and agrarian. structures. The fragility of the environment and the variability and shortage of rainfall have led to judiciously adapted structures geared toward protection of the environment as providing the only guarantee of existence. Serere agriculture offers a good example of the degree of adaptation which has been attained in arid bioclimates. The Sereres are peasants living in western Senegal, a region with poor soil and low, variable rainfall. They have succeeded in maintaining the fertility of the soil by planting useful trees in the cultivated fields, making regular use of the bush fallow system and adding manure. They have managed to feed themselves under difficult conditions while maintaining a stable environment even with a dense population.

Other examples can also be cited, such as the Dogoan and Hausaland regions in northern Nigeria, where population has reached a high density without degrading the environment, thanks to the fallow system, crop growing under the shelter of trees, and the use of manure.

How have these peoples, to whom outsiders might-mistakenly-apply the term "primitive," been able to come to terms with their natural environments, even conserving these environments? The answer may be found in the cohesive social systems of these groups which have enabled them to create and organize appropriate ways of farming.

Whatever strategy is adopted for the management of arid areas, enduring social structures such as these should not be neglected. Enhancement of these structures would bring nothing but benefits. Simple judicial or legislative changes would suffice to ensure that these structural groups, which are in fact management and action units, be officially constituted and recognized as the key element in land management. In addition, simple improvements of traditional techniques, which can be understood as mastered by the population, are very important. These should be adapted to local ecological conditions and should require only a minimum of imported products or experts.

The role of technical assistance would be to provide continuing advice, information, training and follow-up in the field on all operations involved in the establishment, management and utilization of the plant infrastructure and soil improvement. The essential requirements are to understand the needs of the people and ensure their active participation in forestry activities. This presupposes a real dialogue with the rural communities in order to make them truly aware of the contributions of trees and forestry activities and of the necessity to integrate them into plans for the management of their land. This dialogue, this information, this training must be based on a thorough knowledge of social and economic structures and of the requirements of the rural communities.

The technical abilities required for this type of assistance are certainly much broader than those traditionally needed to manage a protected area, for instance. Henceforth, technical experts will have to find ways of incorporating trees into land-management plans and other forestry activities with the technical support which will enable them to face up to growing, and changing, requirements. This will require a multipurpose orientation which will take into account the objectives of agricultural stabilization and wood production, the necessity to conserve the environment and the desirability of full integration into rural development.

It is essential that there be close cooperation among the various services to which the technical personnel are attached and the agencies working in planning, assistance and distribution of facilities. If necessary, increased responsibilities should be delegated within the forestry administration itself. This would lead to a progressive reorganization of the forest services and the recruitment of non-foresters (specialists in animal production, agriculture, veterinary science and sociology who could collaborate with foresters and form a truly versatile forest service.

Planting trees to stabilize agriculture is more costly the more arid the climate and the more degraded the soil. What is really involved is reconquest of the soil based on the establishment of a ligneous infrastructure. Since this represents an enormous expenditure, it can be easily understood why there should be hesitation about undertaking it. It will, however, have to be undertaken sooner or later. It is not sufficient merely to mobilize the local workforce for multipurpose plantation work after education and active propaganda; they must also be given all. the help necessary to obtain for themselves the means necessary for this new activity. In other words, it is necessary to provide assistance based on an obligation on the part of the state and commensurate with real requirements. This assistance may., according to the circumstances, be limited to education, organization and demonstrations, or it may take the form of material assistance: donations, subsidies and loans of money or material.

Such assistance, based on the incorporation of trees by and for the people, will cost less than large-scale reforestation on state lands. In fact, for the same amount of money, the achievement, measured either by area restored or by number of trees planted, will be much greater than if the work is carried out by the administration alone. Finally, this assistance will do more for the rural economy than could be expected from wood production alone.

Arid zones present problems of land use and of stabilization of the bases of agricultural production. Forests, trees and shrubs, as well as annual plants, have an important role to play in this connection and represent perhaps the primary means of arriving at a balanced rural economy and perhaps even the only way of avoiding degradation of the land. As elements essential to the overall stability of agriculture in these zones, trees cannot be relegated to a secondary role but must form an indispensable component of rural management, and this must be managed with and for the people within the framework of a new administrative orientation and with adequate financial and technical assistance.

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