Abstract：Hydrological data were measured during two years(from 2004 to 2005) within <i>Cunninghamia lanceolata</i>(Lamb.) Hook.plantation at Huitong Ecosystem Research Station of Central South University of Forestry and Technology in Hunan Province,Southern China,then change of stand productivity were analyzed.Atmosphere precipitation has provided moisture content needed by <i>Cunninghamia lanceolata</i>(Lamb.) Hook.growth not only,and the precipitation leached from the tree leaves and stems to bring nutrient into the stand.Precipitation was one source for the water and nutrient of <i>Cunninghamia lanceolata</i>(Lamb.) Hook.plantation in catchments.Trees grows though seasonal variation accepting self rhythm effect,however,monthly rainfall determined water and nutrient supply to the stand in growing seasons,then effected the stand productivity.Growing ratio of <i>Cunninghamia lanceolata</i>(Lamb.) Hook.plantation were matched with soil moisture.The transpiration from forest trees related with the photosynthesis in some degree,however,it was not said that transpiration loss of water could indicate the photosynthesis intensity in the stand,because it was controlled by trees physiology.In a forest ecosystem,transpiration lost water but preserved the nutrient,however,runoff lost both of them,it was that the water output from the ecosystem effected the stand productivity.
2008, Vol. 6 
