走可持续发展之路丰宁林业调查侧记北京林业大学张青一、丰宁林业走可持续发展之路的必要性丰宁地处河北省北部，燕山北段，京津周围，滦潮河水系上游，所以丰宁林业对京津周围生态环境的改善具有重大意义。丰宁是北京用水的发源地，但是由于沙化危害，潮河水携沙直入密云... Take the Road to Sustainable Development Fengning Forestry Investigation Sidelights Beijing Forestry University Zhang Qingyi, Fengning forestry and the need for sustainable development Fengning is located in northern Hebei Province, northern Yanshan, around Beijing and Tianjin, Luanchaohe River Therefore, Fengning forestry on the improvement of ecological environment around Beijing and Tianjin is of great significance. Fengning is the birthplace of water use in Beijing, but due to the hazards of sandification, the tidal river flows into the sand and clouds ...