The dependency of latent heat flux on vapor pressure deficit in lowland evergreen forest in Cambodia

Most of the evergreen broad-leaved forest in the Indochina peninsula has been replaced by agricultural land or deciduous forest as a consequence of reclamation or timber cutting, and only a small area of evergreen broad-leaved forest now remains in Cambodia. This remaining forest is under development pressure caused by Cambodian reconstruction. The evergreen broad-leaved forest in there is reported to transpire 6 mm day-1, even in the late dry season, which is almost the same as the rate in the rainy season, despite the surface soil. It is thought that tall trees with extensive root systems use soil moisture from soil layers deeper than 250 cm.

Moreover, the seasonal course of evapotranspiration is much similar to vapor pressure deficit than net radiation. This cause was large roughness length to be 7.5m. This very large roughness length might be caused some emergent trees with maximum height is around 46m in spite that averaged canopy surface height is 27.4m. Omega factor is estimated to be 0.11 in average, 2004.