森林是林业发展的物质基础。在地球上的五大自然生态系统———森林、海洋、沙漠、草原、湿地中，森林生态系统是物质最丰富、对地球生态环境调节功能最强的一个生态系统。社会和国民经济的可持续发展离不开森林。随着人类对可持续发展认识的提高，对林业的要求也发生了重大变 Forests are the material basis for forestry development. Among the five major natural ecosystems on Earth - forests, oceans, deserts, grasslands and wetlands, the forest ecosystem is the most abundant and most eco-friendly ecosystem of the Earth’s ecology. The sustainable development of society and the national economy can not be separated from the forest. With the improvement of human understanding of sustainable development, the requirements for forestry have undergone significant changes