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The semi-arid lands of the world are characterized by low and unreliable rainfall, with lack of soil moisture during all or part of the year being the predominant limitation to vegetative growth. Soil erosion, salinity, nutrient deficiencies and soil texture may also limit tree establishment. These lands are often quite fragile systems, where agriculture is frequently a marginal economic prospect. Yet the pressure to expand agricultural production in these areas is increasing rapidly, and the results of imprudent expansion are often quite damaging to the long-term productive capacity of the land. Establishment requirements for shelterbelts in semi-arid areas are similar to those encountered everywhere, with a general need for good site preparation, effective control of competing weed and grass growth before and after planting, and protection of plants from domesticated stock and vermin. The limitations of available moisture in this zone require special importance to be attached to plant/water relationships at the time of establishment. Consideration should be given to supplementary watering by hand methods or by establishing irrigation systems, including drip or trickle irrigation. Tree establishment methods which may be considered include hand- and machine-planting, as well as direct seeding and natural regeneration. The long-term survival and effectiveness of shelterbelts in semi-arid areas depends on proper establishment, good designs and careful choice of species. It is evident from published reports that there is a common range of species used in many parts of the world, including in particular, species of the genera Acacia, Casuarina, Leucaena, Pinus, Prosopis and Tamarix. A number of individual species are listed and classified for locality and primary uses. Indigenous species should always, however, be the first to be considered in any planting project. The need for planting of new shelterbelts in semi-arid agricultural areas could be reduced if proper land-use planning is applied during the initial development phase of the farmland. Much of the shelterbelt planting in these areas is required to redress particular problems arising from unwise clearing of native vegetation. Frequently, these problems, especially erosion and salinity, could have been avoided if the nature of the land was given proper consideration prior to development, and native tree or shrub cover retained and managed in sensitive localities. The most effective and economical land protection will, in the long term, be provided through proper land use, with the integration of forest or woodland management with agricultural production.