Abstract:Sap flux densities (SFD) of two eucalyptus (\%Eucalyptus urophylla\% S. T . Blake) plantations were measured by heat pulse method during September 1999 t o September 2000 at the two study sites, Hetou and Jijia, located in Leizhou Pen insula, Southeast of China. The diurnal and seasonal dynamics of SFD were quantified, and the relationship between SFD and environmental variables were also evaluated. \;We selected four days (between June 15 to 18, 2000, just after rainfall) to study the diurnal fluctuation...