我省西部地区,水土流失严重,土壤瘠薄,植被稀少,给植树造林带来一定的困难。过去,这个地区营造的人工林绝大多数为油松纯林,既不利于改良土壤,又易遭病虫危害,火险性亦较大。因此,积极营造混交林,已日益成为生产上的迫切要求。混交林具有充分利用环境、改良土壤、减少病虫危害、降低火险性、提高树 In the western part of our province, serious soil erosion, infertile soils and scarce vegetation bring some difficulties to afforestation. In the past, the vast majority of planted forests in this area were pure pine trees, which were not conducive to soil improvement, but were also easily endangered by pests and diseases and were more dangerous. Therefore, actively creating mixed forests has become an increasingly urgent requirement in production. Mixed forest with full use of the environment, improve soil, reduce pests and diseases, reduce the risk of fire, improve the tree