1. phase: Comparison of the water balance of an oak and a grassland stand
In European countries increasing attention has been paid to the interaction of groundwater resources and afforestation. In the context of climatic change the knowledge of the water balance of natural ecosystems is crucial. The water balance components and groundwater consumption at two contrasting sites (oak and grassland stand) were estimated by calibrating a Hydrus 1-D model to fit soil moisture measurements and groundwater levels for a two year period.
Meteorological variables, leaf area index, root fraction with depth, soil water content and groundwater level were measured at both sites.
For the oak stand the estimated annual transpiration is 582 mm, the interception loss is 183 mm and evaporation is only 30 mm. The similar results for the grassland site are 370 mm, 93 mm and 160 mm, respectively. The annual groundwater transpiration was almost three times higher in the forest (211 mm) than at the grassland (73 mm). The model simulations and the groundwater fluctuation method show that transpiration and groundwater consumption from the oak forest exceed those of the grassland.