Planting Density of Pinus tabulaeformis Plantation in Sunny Slope of Daqing Mountains in Inner Mongolia

In this paper,the transpiration characters of 12-year Pinus tabulaeformis plantation,soil evaporation,soil moisture and slope runoff have been tested.The reasonable planting density of Pinus tabulaeformis plantation has been calculated by use of the theory of environmental capacity of precipitation resource and water balance.The results show that the reasonable planting density should be determined by the environmental capacity of precipitation resouce in local area.In the sunny slope of Daqing Mountains in Inner Mongolia,under the condition of the mean annual precipitation at 300~400 mm,the suitable planting density of Pinus tabulaeformis plantation should be 992~2 811 plants/hm2,and the corresponding planting space is 3.0 m×3.4 m~1.8 m×2.0 m.