In this paper, the growth characteristics of individual trees, enzyme activity, photosynthesis, water potential, shape anatomical structure of 4 year old poplar has been studied. The drought resistance of six clone poplar has been measured by comprehensive evaluation of the subordinate function. And on this basis, using grey relational analysis to get lerance indexes quality sorting of 15 projects of six poplar clones. The stem analytical methods used for studing the mature forest growth, development and up...