论文部分内容阅读
文登市自 1980年秋开始封山育林 ,经过 2 0年的实践 ,封育区比非封区植被盖度提高 8.6 %以上 ,幼树密度提高 78%以上 ,6年生赤松树高生长量增长 6 0 %以上 ;封育区土壤有机质和养分含量明显提高 ,林内温湿度条件明显改善 ;赤松毛虫和松干蚧的天敌种类和数量增加 ,有效地控制了松毛虫和松干蚧的蔓延 ,松毛虫虫口密度由封育前的 2 0头 /株下降到 0 .44头 /株 ,松干蚧有虫蛛率降低 5 0 %。
Wendeng City started to seal off hillsides for afforestation since the autumn of 1980. After 20 years of practice, the coverage of vegetation in sealing area increased by more than 8.6% over the non-seal area, the density of saplings increased by more than 78%, and the growth of 6-year-old red pine trees increased by over 60% ; The soil organic matter and nutrient content in the enclosure area increased significantly, and the temperature and humidity conditions in the forest significantly improved. The species and quantity of natural enemies of Cydonia grandis and T. sinensis increased, effectively controlling the spread of pine caterpillars and pine caterpillars. 20 heads per plant down to 0.44 heads per plant, and the rate of pest infestation decreased by 50%.