Introduction: Perhaps one of the great causes of migrations of Aryan tribes, five thousand years ago, from the territory of northern Asia, Iran, India and Europe which caused great changes in human life and civilizations was to reach new pastures. Since human food supply is mainly from agriculture and animal husbandry, and water resources, land, livestock and pasture are limited, providing food products from these resources needs proper use and scientific attention to these resources and to maximize the utilization and maintenance of them. Natural resources have an important status in social and economic development of the world. Unfortunately, in many countries especially in developing countries, increasing population, rapid urbanization, lack of knowledge about importance of natural resources along with inappropriate planning resulted in rapid degradation of forests and rangelands.