The relationships of the transpiration rate of nine species of coniferous and broadleaf young trees to the water potential of their leaves and to the environmental factors were determined by means of a QK-1 stomatograph and a pressure chamber. These young trees are Finns sylvestris var.mongolica, Populus cathayana, etc. The data obtained were analysed by polynomial linear regression and stepwise regression. The results from statistic analyses show that, under the condition of water well-fed soil, the transp...