一、引言杨树是温带最速生的阔叶树种,毫无疑问,这种速生特性同杨树在营养生长期内持续的生长量很大有关,同它的蒸腾强度和光合作用大、根系生理活动能力强也很有关系(peдbko1975)。杨树的生物物质循环与能量转换比其它树种都要大得多。概括地说,这些因素都是构成杨树速生特性的生态——生理基础。 I. INTRODUCTION Poplar is the fastest temperate broad-leaved tree species in the temperate zone. There is no doubt that this fast-growing characteristic is closely related to the continuous growth of poplar in the vegetative growth period. With its large transpiration intensity and photosynthesis, Strong ability is also very related (peдbko1975). Poplar biological material cycle and energy conversion than other species are much larger. In a nutshell, these are all the ecological-physiological foundations that make up the fast-growing nature of poplars.