杨树是速生用材树种,主干通直,材质较优,适应性强,繁殖容易,已普遍用于营造用材林、农田防护林和四旁绿化等方面。国产种及外来引进种加在一起,种类繁多,名称混乱,形态近似,因此识别杨树有一定困难。西北农学院林学系教授牛春山著有《陕西杨树》一书,基本搞清了陕西的和外来引进的主要杨树种类。该书编有系统检索表及每个种的形态 Poplar is a fast-growing timber species, trunk straight, superior material, adaptability, easy reproduction, has been widely used to create timber forests, farmland shelterbelts and greening and so on. Domestic species and imported species together, a wide range of names confused, morphological approximation, so identify poplar has some difficulties. Northwest College of Agriculture Professor Lin Chunshan with “Shaanxi poplar,” a book, the basic out of Shaanxi and foreign introduction of the main poplar species. The book compiled a systematic search form and each species of form