Ch08

1. INTRODUCTION

The dimensions of conservation and restoration action in the arid and semi-arid lands are very varied, according to the local situation. The following approaches can be applied, some of which reinforce each other to attain objectives of sound land husbandry:

Land use planning: zoning and integration of the various land uses to ensure optimal production of goods and services from the land resources;
Preventive measures: to control grazing, deforestation and misuse of the biomass and to prevent fires and pests;
Establishment of protected areas: for the in situ conservation of genetic resources, for national parks and recreation, for wildlife management, for scientific purposes;
Management systems: range and silvo-pasture management, watershed management, natural regeneration and forest management, wildlife ranching, fire control and use of controlled fires;
Revegetation: introduction of shrubs and trees for fuelwood and fodder production, to supply timber for rural needs and to enhance protection, air seeding, establishment of greenbelts around human settlements;
Land rehabilitation: watershed restoration, torrent and gully control, mechanical and biological measures to control run-off and promote infiltration in degraded land, control of sediment from bad lands and severely eroded areas, where these measures have an economic justification (protection of human settlements, infrastructure, water resources and valuable cropland);
Forestry support to farmland: windbreaks, shelterbelts, woodlots, agroforestry systems, introduction of multi-purpose trees, fodder trees and fuelwood species, introduction of nitrogen-fixing species;
Land reclamation: stabilization of sand dunes (coastal and continental), reclamation of saline soils, reclamation of marshland;
Control of desert encroachment: stabilization of sand dunes affecting oases, cropland and infrastructure, establishment of large-scale shelter-belts (e.g. China, Algeria, Nicaragua, USSR).
Water conservation and harvesting: phreatophyte control, vegetation manipulation to increase water yield, water spreading, devices to promote ground water recharge and storage, dew harvesting techniques, mulching and other techniques to reduce evaporation losses in cropland and surface water.

In the following paragraphs we will summarize thematic reviews covering some of the key tools and techniques which are most common in forestry programmes for restoration and conservation of the drylands.

2. CONTROL OF WIND EROSION

Shelterbelts and windbreaks provide several benefits, including protection against wind erosion and sand drifting, returns in fuelwood or poles, wildlife refuge sites and aesthetic and micro-climatic advantages to human beings. But their most important contribution lies in their contribution to increased crop and livestock yields.

In general, the information available consistently demonstrates the utility of shelterbelts in the Mediterranean climate. In the Sudano-Sahelian zone, the few measurements and observations available tend to indicate that shelterbelts are detrimental to rainfed crops. On the other hand, the scarce biological and micro-climatic measurements available provide encouraging evidence on the favourable effect of shelterbelts in irrigated areas. However, it must be concluded that for rainfed crop cultivation, means other than shelterbelts must be found for combating wind erosion. Symbiosis of agriculture and trees appears a potential method of reducing wind speed and improving the local micro-climate.

In the case of wind erosion and dune stabilization, several countries have instigated dune stabilization programmes which include schemes for dune fixation, afforestation and attainment of goods - such as fuelwood - as programme objectives.

Dune control effects to-date have largely been undertaken on the basis of trial-and-error experience at a few locations within the arid region. Despite the fact that several countries have launched large dune stabilization control programmes, much still remains to be learned both in terms of basic scientific facts and of technology. For instance, not very much is known about specific plant species which may best be used on the various ecological "niches" of the dunes, although we know from researchers that dune ecological conditions are quite varied. Consequently, only a few species are used in most dune work. There is scant knowledge on plant-sand-water relationships and on other physiological questions. No-one seems to have much information on the hydrological and ground-water topic vis-a-vis afforestation of dunes. Would thirty year-old plantations on dunes begin to "mine" all the capillary and ground-water, and then begin a die-off process? From a practical viewpoint, much could still be learned about more economical fixation procedures, better long-range management plans, pest and disease control, nursery/planting procedures, silvicultural systems, genetic development and multipurpose species. Dune afforestation, nearly an "infant field" of forestry, is now in a trial-and-error phase but is in need of a much better scientific foundation.

3. WATERSHED MANAGEMENT

The water relationships of arid zones are more critical to a greater number of people than in humid regions. Water is always in critical balance in arid ecosystems and this balance is being upset by man and livestock at alarming rates. Perhaps of greater significance is the loss through erosion of the soil of the soil reservoir. Not only is the soil reservoir the principal means of controlling the flow of water from upstream watersheds, but, more importantly, it is also the basis of the production of renewable resources on these watersheds.

It is obvious, therefore, that present land use patterns on watersheds in the arid regions of the world must be reshaped so that delicate water and soil relations are not pushed beyond their limits. As the number of people and animals living in arid zones climbs, and the quality of the land on which they live declines, the detrimental impacts of excessive grazing, deforestation and improper agriculture will continue unless solutions are found and implemented. These solutions should consider inter alia the upstream/downstream physical and socio-economic interrelationships.

The purpose of watershed management is to understand the hydrological, ecological and human relationships and then to apply this understanding to rehabilitating degraded areas, to conserving water, soil and other natural resources and to improving land use for increased long-term productivity. Watershed management efforts develop most often in connection with water development schemes and the protection of water supplies in areas where the water balance is deficitary. In most cases watershed restoration is justified to reduce sediment yield and prevent silting of reservoirs, intakes, waterways and harbors, ensuring that the life span of these works of infrastructure is not shortened. Wherever human settlements, intensively used cropland and touring facilities are endangered by flash-floods and mud-flows, as is common in many Mediterranean environments, heavy investment in slope stabilization, torrent control and river channel stabilization may be justified. On the other hand, in sparsely populated areas, where degradation of the vegetation cover and over-grazing have caused alteration of the soil-water-plant system, extensive and low-cost measures should be adopted to mitigate downstream effects. Increase in water yield may be a must when the water resources for human needs or for food production are scarce; however, very limited research exists (USA, Israel, Australia, India) on the techniques for vegetation manipulation and on the mechanical or chemical measures to reduce vegetation evapo-transpiration losses without affecting water quality.

The basic technologies required to manage watersheds under the various types of situations are known. A difficulty, however, is in getting local people to accept conservation measures, which call for participatory approaches in the planning and implementation of watershed management efforts.

4. WATER HARVESTING

The development of water resources in arid regions, at present and in the recent past, has been concentrated on large-scale irrigation projects. However, these projects provide few direct benefits to the small land holder or nomad, who must survive within the constraints of his environment without the benefit of new technologies appropriate to his needs. Fortunately, water harvesting offers one method of improving the livelihood of these people.

The purpose of water harvesting is to either augment existing water supplies or to provide water in situations where other sources of water are not available or developmental costs are prohibitive. The aim is to provide this water in sufficient quantity and of a suitable quality for the intended use.

In essence, a water harvesting system consists of a catchment area, which can be natural surfaces, artificial surfaces or combinations thereof and a water storage facility. There are many options regarding the geometric configuration of the system, as might be expected. The strategy taken in developing a water harvesting system depends upon a number of constraints, including:

the quantity and quality of water required to meet the need;
the amount, seasonal distribution and variability of precipitation;
the materials, labour and machinery available;
the provision for maintenance;
the need for acceptance by the local community.

Numerous water harvesting systems have been installed in the arid regions of the world. Although many are in experimental stages, most of the systems have met with success. Case examples can be found in Mexico, India, Iran, Pakistan, Australia and the United States and more water harvesting systems are currently being planned and implemented elsewhere.

A related aspect which is at an incipient stage is water harvesting from dew, which is an important source of water in areas such as the Atacama desert.

5. LAND RESTORATION AND REVEGETATION

Land restoration and revegetation of degraded arid lands is imperative to increased food production, not only to support the present population of 300-600 million people but also to provide for the anticipated future populations. Specifically, through land restoration and vegetation, the following goals are sought:

protection of soil from water and wind erosion and, as a result, maintenance of its fertility;
protection of watersheds and water courses to attain a regular flow of high-quality water;
stabilization of sands and sand dunes;
enhancement of vegetative resources for fuel, construction materials, fodder, food and forage, and other products for use by man.

In general, the majority of the countries in the arid zones have declared policies on land restoration and revegetation. Intentions of protection, conservation and development of the natural resources are, in most cases, explicitly stated. A major problem, however, is converting policies into action. Biological and socio-economic constraints are usually present.

To a large extent, the technologies of land restoration and revegetation are known at least in a broad sense. Difficulties are encountered, however, in extrapolating these technologies for application in specific contexts. The availability of materials, labour and machinery may be limited and the acceptance by the people of the proposed technologies and their ability to implement the measures can be restricting. Nevertheless, the consequences of not imposing the necessary "corrective actions" is well illustrated through a number of case studies.

6. REHABILITATION OF SALINE ENVIRONMENTS

A special form of land restoration is the rehabilitation of saline environments. It has been estimated that nearly 10 per cent of the world's land area is salt-affected. Fortunately, through appropriate technologies, many of these salt-affected lands can be transformed from sources of erosion and desertification to areas producing valuable forage, fuel and other products.

Engineering solutions, the mainstay of rehabilitation programmes in the past, are unsatisfactory in many situations, because of water shortage, high costs and material shortages and technical problems. However, a possible alternative is to grow plants possessing sufficient salt or alkali tolerance to withstand the existing conditions without reclamation. Increasing attention is being focused on the use of highly salt-tolerant plants for growing on salt-affected soils or for irrigating with saline water.

The rehabilitation of saline environments is dependent on successful establishment of a vegetative cover. Depending on the site conditions, grasses, shrubs or trees may be suitable. In severe cases, it may be necessary to use "pioneer" species to ameliorate the site sufficiently for other more desirable plants to become established. For all situations, a careful screening of plants, against suitability criteria, is a pre-requisite.

To achieve success, it is necessary to also select an appropriate establishment method and to provide for sound management of the new resource. Recommended methods of rehabilitation are available, although these general methods may have to be "localized" for a particular area. Case studies in Ethiopia, Iraq, Pakistan and West Australia show that in many arid zones, the halophyts utilized in reclamation programmes can be grazed by livestock. Grazing experiments in saline environments continue, however, to formulate the most appropriate range management practices. Other uses of plants that are salt or alkali tolerant are also being studied.

7. WILDLIFE CONSERVATION

The wildlife resource in the arid zone has recently attracted increasing attention. However, only a few countries of the arid region are represented in the 1974 United Nations List of National Parks and Equivalent Reserves. Information on the ecological requirements of the indigenous animals is scarce and scattered. Few studies have been made on distribution, reproduction and potential utilization of wildlife.

Among the obstacles to the development of the wildlife resources of the arid and semi-arid regions are habitat deterioration, often associated with expanding human populations and changing land use practices, increasing use of pesticides which threatens the existence of certain species of birds and mammals, and poaching and exploitation for trade. On the other hand, there seems to be an excellent opportunity in the arid region for diversifying rural income by improving the management of national parks and wildlife resources.

8. GENETIC RESOURCES CONSERVATION

The importance of plant and animal breeding in respect of dry areas development cannot be over-emphasized. Breeding programmes for plants would require the introduction of new germplasm in order to develop varieties and strains resistant to drought apart from other desirable characteristics such as high yields, palatability to animals, low fuel value (against fires) and resistance to pests and disease.

Progress in breeding greatly depends upon the availability of broad genetic variability which exists in the natural flora and fauna of marginal areas. But this variability is rapidly disappearing. Coordinated action is, therefore, required at the regional level to preserve the genetic variability of plant and animal species, through the establishment of gene pools and exchange arrangements for genetic material.

9. ISSUES AND GAPS

In the following paragraphs some of the key issues related to the contribution of forestry to restoration and conservation of the arid environment will be pointed out for discussion. The major gaps in knowledge and in action are also identified, to promote research and cooperation in the strengthening of field programmes, as possible elements for inclusion in the Plan of Action.

9.1 General (*)

(*) These issues might also be considered in discussing the institutional aspects.

As indicated in the Introduction, there is a variety of approaches to cope with the problem, which may supplement each other. Some crucial points for discussion are:

what should be the strategy for planning and coordinated development of such action, considering: (i) that most countries do not have an appropriate institutional framework; (ii) that coordinated plans to combat desertification, enhancing the role of forestry need to be formulated; (iii) that resources to implement action are scarce in terms of qualified manpower, funding, etc.;
which approaches should be favoured, according to the various ecological and socio-economic situations, taking into account criteria such as: (i) cost-effectiveness; (ii) effective contribution to check desertification and enhance production and protection; (iii) local levels of know-how and traditional techniques which may be favoured;
how should technological packages for conservation and restoration be conceived in order to: (i) attract political interest and mobilize financial resources; (ii) be attractive to the local community, ensuring their involvement; (iii) have a short-term and visible impact in checking environmental degradation;
how should implementation be approached: (i) large scale; (ii) limited to demonstration areas; (iii) selecting pilot villages/watersheds/districts; (iv) within a public works approach; (v) through local community participation.

9.2 Shelterbelts and windbreaks

Some particular issues for discussion on this topic are:

what is the effectiveness of large-scale shelterbelt establishment to control desertification and enhance productivity, according to experience (USSR, China, Algeria, Nicaragua, Senegal);
are shelterbelts detrimental in some cases to rainfed crops? Should windbreaks be planted along unlined canals?

Some aspects which appear to require further study and research are:

(i) testing various species (and combinations thereof) for different sites and types of crops to be protected;

(ii) testing of various designs (spacing, frequency, width, height including agroforestry systems) of shelterbelts;

(iii) studies on shelterbelt economics under various conditions;

(iv) cultural and management problems of belts, including the question of root competition with crops.

9.3 Sand dune stabilization

The main issue for discussion on this topic is the experience obtained in areas where stabilization and afforestation programmes have developed for several decades: (i) what economic use can be made of the area without creating destabilization hazards; (ii) does the vegetation mine the ground-water and suffer as a result a die-off process?

Some topics identified which merit further study and research are:

(a) the technical biological/mechanical/chemical methodologies for dune stabilization, including testing of new methods;

(b) the economics of various fixation and rehabilitation techniques;

(c) the various physiological, biological, hydrological and physical processes of dune vegetation establishment, growth, survival and reproduction;

(d) exotic and native species trials and botanical testing to identify new or better dune vegetative species; nursery and planting techniques;

(e) development of land-use management and silvicultural schemes for long-term productive and profitable use of rehabilitated dunes, e.g. fuelwood production, charcoal;

(f) the sociological considerations of these activities in toto and the questions of planning desert rehabilitation as a multi-disciplinary effort;

(g) investigation of other varied productive uses of rehabilitated dune areas, e.g. honey-bee raising, forage tree production, relation of dune stabilization to irrigation development, shelterbelts and other agricultural pursuits;

(h) the need for a data bank, monitoring of programmes and the exchange of information;

(i) centres for education, training and extension work in the topic.

9.4 Watershed management

Some key issues to better orientate restoration and management of watersheds are:

how to induce the rural population to accept changes in land use and to introduce management systems and restoration measures which benefit down-stream interests;
ways by which the linkage (and the financial arrangements) between water resources development and watershed management can be strengthened;
how to ensure the involvement of the local community in the planning and implementation of work, including the most efficient use of food for work and other types of incentives;
strategies to promote integrated agro-silvo-pastoral development, matched to the variability of precipitation patterns, to erosion hazards and to the requirements (timing, quantity and quality) of water resources management.

Some technical aspects requiring further study and research are:

simple monitoring systems to assess the environmental, economic and social impact of watershed management measures;
choice of native and exotic species best suited for revegetating eroded sites (grasses, bushes, trees);
economic methods of torrent control appropriate for the specific conditions of marginal areas;
controlled use of fire for pasture improvement and as silvicultural practice;
appropriate techniques for water yield improvement.

9.5 Water harvesting

Gaps in knowledge exist in the planning and implementation of water harvesting systems:

because of the high variation in precipitation from year-to-year in arid regions, long-term, historical records are necessary but unfortunately often lacking;
information on the minimum water requirements for agricultural crops is incomplete;
quantitative information on the quality of water collected by water harvesting is limited;
the "economics" of water harvesting is not fully documented over the long-term;
the physiology of species which have the ability to trap moisture directly through the leaves should be studied (Prosopis, Acacias, etc.);
ground water recharge and storage systems to prevent water losses as flash-floods.

9.6 Land restoration

Regarding the topic of land restoration and revegetation, the following require serious consideration:

site classification to identify appropriate land use which is a prerequisite to the selection of land restoration and revegetation technologies;
knowledge of potentials for better utilization of indigenous vegetation;
plant/animal relationships are lacking, although knowledge is required for better utilization of the natural resources.

9.7 Reclamation of saline environments

For the rehabilitation of saline environments, important gaps in knowledge include:

a need to assess the capability of salt-affected lands to distinguish between areas for which the prospects of being returned to "non-haloplytic" crop production are good, and those that are likely to remain salt-affected;
more complete evaluation of plants which can grow in saline environments.

9.8 Revegetation and management of natural vegetation

Some key aspects which require study and research are the following:

(i) surveys of vegetation forms and types;

(ii) ecological, botanical and physiological studies, particularly the capacity of various species to grow and reproduce under environmental stresses;

(iii) vegetation-environment interrelations. These are very delicately balanced. For instance, even slight changes in micro-climatic conditions affecting either water supply or water needs often tip the precarious balance either to success or failure in respect of many cultivated plants. And it is precisely in this dimension that a better understanding of the vegetation/environment relations assumes economic significance apart from purely scientific importance. Studies in this area could include:

vegetationmicro-climate relations, including answers to practical questions such as to what extent, under which conditions and at what cost could vegetation be employed to reduce aridity;
vegetation-soil relations: how vegetation could be employed in practice to restore soil fertility in already degraded sites; which pioneer species could be used to reclaim degraded, alkaline or saline soils; which tree species could make possible the cultivation of under-crops (c.f. Acacia albida in parts of the Sahel), or control soil erosion;
vegetation-water relations: whereas the role of vegetation in stabilizing water supply is a well-established fact, the vegetation/total water balance relationship has not yet been determined. Similarly, the water requirements of most plant species are not well known. Work needs to be done on the role of vegetation in rainfall interception; condensation of dew; evaporation; transpiration; run-off prevention; percolation, etc., in order to make full use of the favourable influences of vegetation in water conservation and use.

9.9 Afforestation

The main areas for studies and research in this field are:

(i) species and provenance trials of trees and bushes indigenous to the arid region;
(ii) site diagnosis techniques, including soil survey and bioclimatic investigations to facilitate choice of species and introduction of exotics;
(iii) site preparation and amelioration techniques, including the use of terracing (manual and mechanical), deep ripping, methods for reducing salinity or making use of run-off water;
(iv) improvement of nursery and planting techniques, including the efficient use of containers;
(v) improvement of tending, protection (particularly from fires and grazing) and management of plantations;
(vi) special studies on important genera/species, e.g. Acacias, Eucalyptus, Tamarix, Quercus, etc.;
(vii) use of sewage water in plantations and its environmental effects.

9.10 Wildlife, wildlands and national parks

Measures/actions to be initiated in this area could include:

National level

recognize the significant role that wildlife can play in the development planning of rural areas and the necessity of integrating it with forestry development programmes and multiple land use; strengthen institutional structures for the management of wildlife, wildland and national parks resources;
review national networks of parks and reserves, with a view to ensuring the conservation of the genetic resources of representative samples of each ecological zone, in particular to ensure their protection from degradation by human activity;
initiate programmes of conservation education at all levels;
integrate forestry development with outdoor recreation planning in the vicinity of urban centres.

Regional level

establish co-ordinated research and pilot development programmes aimed at evolving improved techniques for the management of wildlife;
establish a regional training programme in wildlife and national parks management for the lower cadres of staff. Such a programme would envisage courses organized at the country level and conducted by instructors who would visit countries in rotation;
co-ordinate on a regional basis the establishment and management of national parks and reserves, particularly of areas which lie astride international boundaries.

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