Response of Soil Respiration to Soil Temperature and Moisture Regimes in the Natural Forest of Quercus aliena var. acuteserrata Effects of thinning intensity on rain water chemistry of canopies and litters of Quercus aliena var. acuteserrata in Qinling Mountain TURNOVER PROCESS AND ENERGY CHANGE OF FINE ROOTS OF PINUS TABULAEFORMIS AND QUERCUS ALIENA VAR.ACUTESERRATA NATURAL FORESTS IN QINLING MOUNTAINS