Abstract: Kira's warmth index(WI)and Xu Wenduo's humidity index(HI)were used to stndy their relationships with the distributions of the 53 tree species in 233 weather stations in Northeastern China. The results showsed that the WI range of the main species was from 33.5 to 93.6℃ per month and the HI value was from 5.9 to 10.6 mm·℃^-1·month. When the WI value reaches 70℃ per month and the HI value reaches 7.5 mm·℃^-1 for per month, the distribution range of 53 species can be divided into two zones. Finally, we divided five urban forest types in Northeastern China: 1)cold-temperate wet forest type, 2)temperate wet forest type, 3)warm-temperate wet forest type, 4)semi-wet temperate forest type, and 5)semi-wet warm-temperate forest type.

Key words: Hexi oasis, Ecological footprints, Ecological capacity, Ecological surplus/deficit, Sustainable development