Projects of the Institute of Soil Physics

Climate change is leading to more frequent droughts and heavy rainfall events in Austria. The soil water deficits caused by droughts and the altered rainfall patterns pose a risk to forests, as they result in reduced growth, increased tree mortality, and the loss of ecosystem services. The complex interactions between climate change and the response of hydrological components such as infiltration, soil water storage, and runoff are difficult to investigate separately under temporally variable, natural conditions. However, there is an urgent need for detailed knowledge about forest-water interactions to strengthen forests against the impacts of climate change. In this project, controlled manipulation experiments with artificial droughts and irrigations will be carried out in a highly instrumented long-term research beech forest (Rosalia, Lower Austria). We will quantify the use of summer and winter precipitation by the beech trees, as well as evaporation, transpiration, and groundwater replenishment, using stable water isotopes. For this, soil and xylem samples will be analyzed in the laboratory and compared with high-resolution in-situ measurements. In addition, hydrological measurements (runoff, temperature sensors, and tracer experiments) will be used to determine surface runoff, lateral flows, and current evapotranspiration, in order to close the water balance at the catchment level. This project will quantify changes in water flows due to drought and heavy rainfall events to enhance our knowledge of hydrological processes—knowledge that can be transferred to other forests in similar climate regions. The results can provide evidence-based recommendations for forest managers to improve the health of beech forests and their resilience to droughts and heavy rainfall.