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前言淳化县位于西北黄土高原沟壑区的南部,是黄河中游123个水土保持重点县之一。该县自1974年开展大规模植树造林以来,至1979年,森林覆被率由原来的3.5％提高到16.3％,“四旁”植树757万余株,农田林网初具规模,开始发挥防护效益,成为全国林业发展较快的先进县之一。但是由于在造林过程中,对立地条件考虑不够,造林树种单一,人工造林保存率仅为37.28％,有些地方虽已成林,而生长不良,致使造林地的生
Introduction Chunhua County is located in the northwest of the gully region of the Loess Plateau in the north, is one of 123 key counties of soil and water conservation in the middle reaches of the Yellow River. Since it started large-scale tree planting and afforestation in 1974, the forest cover rate has increased from 3.5% to 16.3% by 1979, with more than 7.57 million trees planted on all four sides and the scale of farmland forest network has begun to play a protective role It has become one of the advanced counties with a rapid forestry development nationwide. However, due to inadequate consideration of the conditions of afforestation during afforestation, the afforestation species are single and the afforestation conservation rate is only 37.28%. Although some areas have become afforested and undergone poor growth,