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加大科技含量发展白城生态经济林业的探讨闫红，周树荣（白城市林业局）牛兆宽（白城市林学会）白城市是吉林省西北部半干旱地区。地处东经１２１°３８’～１２４°２２’，北纬４４°１３’～４６°１８’。年均气温４．５℃，有效积温２９８０℃。无霜期１４０天左右。...
Discussion on the Development of Baicheng Ecological Economic Forestry with Scientific and Technological Content Yan Hong, Zhou Shurong (Baicheng Municipal Forestry Bureau) Niu Zhao-kuan (Baicheng Forest Society) Baicheng City is a semi-arid area in the northwest of Jilin Province. Located in the east longitude 121 ° 38 ’~ 124 ° 22’, north latitude 44 ° 13 ’~ 46 ° 18’. Average annual temperature of 4.5 ℃, 2980 ℃ effective accumulated temperature. Frost-free period of about 140 days. ...