中文摘要：

使用澳大利亚GREENSPAN公司SF-300热脉冲树干液流仪与德国UP公司生产的SFS2-M热耗散树干液流仪,对二白杨和临泽小枣树树干液流速率进行了连续1个月观测,对比了这两种树干液流法在测定干液流速率的差异,以及讨论了其产生的原因.结果表明：两种方法对二白杨与枣树树干液流速率的测定结果存在差异,用热脉冲法对二白杨树干液流测定结果高于热耗散法的测定结果,前者测定的日耗水量平均高后者（20.1±18.0）%;而对枣树,则用热脉冲法测定的结果低于用热耗散法测定结果,平均值相差近3倍.这些差异可能与林木树干液流速率存在径向变化及两种方法的测定原理不同导致的.

英文摘要：

In this paper,Gansu Poplar and Linze Jujube sap flow velocities were continually measured by two methods for one month.The two equipments used are SF-300 heat pulse sap flow meters made in Greenspan technology Pty Ltd,Australia and SFS2-M made in UP Umweltanalytische produkte Gmbh,German.The sap flow velocities of Gansu Poplar and Linze Jujube measured by the two methods are compared,and the causes of difference in measurement are discussed.There is an obvious difference in sap flow velocities of Gansu Poplar and Linze jujube measured by HPM and by TDP.As for the Gansu Poplar,sap flow velocity measured by HPM was higher than that measured by TDP,and diurnal water consumption measured by HPM was 20.1±18.0% higher than that measured by TDP.For Linze Jujube,sap flow velocity measured by HPM was higher than that measured by TDP,with an average difference of diurnal water consumption of 3 times mostly.The difference maybe results from the sap flow velocity variety along with radial and the measuring theory that is different for the two methods.