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一“三北”防护林是一项治理生态环境、造福子孙后代的伟大事业。1978年国务院决定建设“三北”防护林体系,这对本区经济发展、国土整治和生态环境的改善具有重要意义。为了解“三北”防护林体系建设的现状和已采取的经济政策、技术措施所取得的效果,国家把“三北”防护林遥感综合调查列为“七五”重点科技攻关课题。吉林省西部是东北平原农田林网区防护林建设的重点地区之一,包括21个县(市),占全省总面积的42.6％。科尔沁沙地东缘的通辽、长岭、双辽等县为沙地覆盖的冲积平原,偏南部有东北——西南向“鸡爪”形较大的沙垅、闭流洼地,其上分布着大小不等的泡沼,在
A “Three Norths” shelter forest is a great undertaking that manages the ecological environment and benefits future generations. In 1978, the State Council decided to establish a “three north” shelterbelt system, which is of great significance to the economic development, land readjustment and improvement of the ecological environment in the region. In order to understand the status quo of the construction of the “Three Norths” shelterbelt system and the effects of the economic policies and technical measures taken, the state has listed the “Three Norths” comprehensive survey of shelterbelts as a key scientific and technological issue for the “Seventh Five-Year Plan”. The western part of Jilin Province is one of the key areas for the construction of shelterbelts in the farmland forest network in the Northeast Plain, including 21 counties (cities), accounting for 42.6% of the total area of the province. Tongliao, Changling and Shuangliao counties on the eastern margin of Horqin Sandy Land are alluvial plains covered by sandy land. In the south, there are large sand ridges and closed flow depressions in northeast-southwest to “chicken feet” The size of the bubble marsh, in