Estimating Transpiration Of Temperate Deciduous Forest In Korea Using Sap Flow Measurements And Eco-hydrological Model

In forests, vegetation is a major factor in the hydrological cycle. Even though the studies of transpiration has been developed, transpiration in trees is still difficult to measure under natural conditions due to canopy heterogeneity, topography, and large size of trees of forest stands. In this study, transpiration was measured by using sap flow measurement, Thermal Diccipation Probe (TDP), first proposed by Granier (1985) in Gwangneung Research Forest, Pocheon-gun, Gyeonggi-do. Average estimated stand transpiration from measuring sap flow was 1.31mm/day (Maximum value : 2.31mm/day) in May and June. We compared this average stand transpiration with the simulated transpiration by eco-hydrological model, RHESSys (Regional Hydrologic Ecological Simulation System). As a result, we found simulated transpiration was highly overestimated. Thus, sap flow measurement has been underestimated transpiration relatively. This difference is possibly caused by scaling up the value from point to tree and stand level.