杨树是我国北方,尤其是青海东部农业区,生长迅速、栽培历史悠久的树种之一,该县广泛营造于用材林、防风固沙林、水土保持林、农田林网及群众四旁植树的主要乡土绿化树种。但是近年来,由于病虫害严重,干旱少雨,杨树生长缓慢,甚至成片死亡。笔者对此进行了调查,发现不同杨树品种? Poplar is one of the tree species that grows rapidly and has a long history of cultivation in north China, especially in the eastern Qinghai Province. The county is widely populated with major native tree species such as timber forest, windbreak and sand fixation forest, soil and water conservation forest, . However, in recent years, due to the serious pests and diseases, the drought and the lack of rain, the poplar grows slowly and even dies. I conducted a survey, found that different poplar varieties?