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Utilization of fodder trees and shrubs (FTS) in the Mediterranean arid and semi-arid zones was initiated after World War I and expanded between 1950 and 1970. A similarly slow expansion has taken place in other arid zones in the USA, South Africa, South America, and Australia. Currently in West Asian and North African ((WANA) countries, the area planted with native or exotic species is about 10(6) ha. Mainly they include three categories of plant species: cacti, saltbushes, and wattles. At this time there is an expansion of hectareage and a diversification of genetic material. The relative success of FTS has a number of reasons. They are tolerant to dl ought and have the ability to accumulate green fodder over several seasons, providing fodder reserves for times of dearth and thus permitting a switch from transhumance to sedentary husbandry. Deep rooting enables them to Peach water resources unavailable to herbaceous species. Their Rain Use Efficiency (RUE) and Water Use Efficiency (WUE) rates provide productivities three to five times higher than rangelands. FTS have a positive impact on soil fertility due to their organic matter production, hence they increase microbial activity, rates of geobiogenic element cycling, and soil structure stabilization. Their above ground biomass, canopy ground cover, provides a microclimatic buffer role for wind, temperature and evapotranspiration, and their landscape roughness factor makes them efficient for erosion and desertification control. Other positive aspects include: the use on non-farming land; general suitability for runoff farming systems; production of valuable goods, such as food, shade, and firewood; providing wildlife shelter; and other benefits. FTS plantations are subjected, however, to constraints that limit their expansion. Their main shortcomings include the cost of establishment, often not affordable by a small farmer; required long-term planning may not be feasible, as a secure land tenure system often is nonexistent. Appropriate methods of cultivation ape not being applied, management, and utilization are lacking, and availability of plant material is limited. Discipline of utilization, allowing regeneration of stands after defoliation is a problem. Identification of constraints indicates needs for research and extension activities. These include reduced-cost of establishment and improved management methods, such as ensuring availability of low-cost seeds and selection of high grade cultivars, and introduction of new high quality exotic species. Additionally, integration into economically feasible and socially acceptable production systems, including joint cultivation with cereal farming and combination with runoff farming techniques, should be developed. Legal, regulatory, and administrative incentives are also needed.