干旱区生态环境知识资源中心

The mismanagement of the forest resources of arid and semi-arid lands is one of the principal causes of desertification. For this reason, the immediate afforestation of these areas, complemented by rational management of forest resources is proposed. However, the lack of basic knowledge about the ecology, genetics and physiology of ar id zone species, as well as the Sociological aspects of the people of these areas have contributed to the failure of various afforestation programs in different parts of the world. Therefore, a series of recommendations and criteria ave discussed which should be considered before initialing afforestation programs. These recommendations and criteria ave integrated into long and short-term afforestation strategies for avid and semi-al id areas. The selection of the appropiate native species for each zone and the origin of the germplasm are two of the most important aspects taken into account in the short-term strategy. The establishment of both genetic and physiological trials related to different kinds of stress will give tw more confidence and will permit us to,select the best alternative or alternatives for carrying out a longterm afforestation program. Any generic improvement and breeding program should ideally permit us to: a) select the best species, b) acquire knowledge about their genetic and environmental variation, c) generate ecological information about the species, d) obtain the best plant material at any moment, e) retain selected genotypes and f) maintain the variability. As it’s an ideal situation, a flexible strategy is recommended, such as the multiple population strategy. The selection of the best species and genotypes for each area, carefully combined with culture and physiology techniques, e.g. tree establishment under drought conditions, will increase the probability of success of afforestation in arid and semi-arid lands of the world. Furthermore, we must take into account the necessities and demands of the human population of these areas.