杨树生长迅速,耐寒,耐旱,易于繁殖,是坝上地区营造农田防护林的主要树种之一。但大面积的杨树纯林,易遭受杨青蛾、柳毒蛾等虫害的猖撅为害,且生长缓慢。为此,如何改造杨树纯林和营造杨树与其它树种的混交林,是当前急需解决的问题。 Poplar growing rapidly, cold, drought, easy breeding, is to create a shelterbelt in Bashang region is one of the major tree species. However, a large area of ​​pure poplar, vulnerable to Yang moths, liu moth and other pest insects rampant damage, and slow growth. For this reason, how to transform the pure forest of poplar and to create a mixed forest of poplar and other tree species is the urgent problem to be solved urgently.