With the aid of TDM (thermal dissipation method) with ICT\|2000TE (Transpiration Environment), the results obtained were as follows: (1) The sap flow rate of Quercus liaotungensis varied differently in sunny days, cloudy days and rainy days, with their maximum value of 12 61 cm·h -1 , 8 71 cm·h -1 and 3 22 cm·h -1 ,respectively. The intermittent sap flow at night was commonly lower than 1cm·h -1 , which testified the existence of root pressure of Q. liaotungensis . (2) In the growth season of July and August, the sample wood of Q. liaotungensis had the average sap flow flux of 60 25cm 3·cm -2 d -1 and total evaporations of 1 346 7 L. (3) The sap flow rate was frequently affected by microclimatic factors. During sunny days and cloudy days, it was mainly affected by the solar radiation, air relative humidity and air temperature. While during rainy days, it was mainly affected by the soil water content and air relative humidity.
