Effects of Forest Community Degradation on Water Chemical of Karst Shallow Groundwater A STUDY ON THE DYNAMlCS OF WATER CHEMISTRY IN CHINESE FIR AND OADLEAVED PLANTATION WATERSHED IN HUITONG Response of Stream Water Chemistry to Rainwater Acidification in the Natural Forest Region of the Qinling Mountains Effects of thinning intensity on rain water chemistry of canopies and litters of Quercus aliena var. acuteserrata in Qinling Mountain Influence of Canopy upon Rainfall in a Regenerative Tropical Mountain Rain Forest at Jianfengling of Hainan Island