萝北林区现有天然次生林面积9.1万ha,每年都要改造和主伐12000亩的次生林,更新树种多以落叶松为主。由于连片的人为采伐后,改变了原来的森林生态环境,破坏了原群落中的营养链索关系,生物网被剪乱,加之食物单一,从而造成取食人工林的害虫大发生。据统计,萝北林区1970年至1980年累计更新保存率仅为71％,其中害虫危害也是一个重要原因。1987年以来,萝北林区探索一种人工选择益鸟栖息的林木来招引益鸟,由鸟类这个森林 The existing natural secondary forest area of ​​Linbei Forest Area is 91,000 ha, and the secondary forest of 12,000 mu is to be reformed and rehabilitated each year. Most of the tree species are mainly larch trees. Because contiguous man-made cutting changed the original forest ecological environment, destroyed the original nutrition chain relations in the community, the biological net was cluttered, coupled with a single food, resulting in pests eating plantation occurred. According to the statistics, the cumulative update rate of Rubei forest area from 1970 to 1980 was only 71%, and the pest damage was also an important reason. Since 1987, Luobeilin District has explored a kind of artificial selection of beneficial birds perched on trees to attract beneficial birds, from the birds to the forest