Water fluxes within beech stands in complex terrain

Area of Science:

• Forest Ecology
• Hydrology
• Climate Science

Background:

• Understanding forest water balance is crucial for predicting ecosystem responses to climate change.
• Beech stands (Fagus sylvatica L.) are dominant in European forests, making their water use a key research area.
• Microclimate variations, such as slope aspect, can significantly influence forest hydrology.

Purpose of the Study:

• To investigate and compare the water balances of two beech stands on NE- and SW-facing slopes.
• To evaluate the performance of two hydrological models (DNDC and BROOK90) in simulating forest water fluxes.
• To analyze the impact of slope aspect on stand transpiration and overall water loss.

Main Methods:

• Continuous measurement of forest meteorological variables.
• Estimation of stand transpiration (ST) using sap flow measurements.
• Application and evaluation of DNDC and BROOK90 hydrological models for microclimate and water flux simulations.
• Comparison of simulated and measured ST.

Main Results:

• Both hydrological models accurately reproduced soil water content dynamics in the top 30 cm.
• Simulated and measured stand transpiration showed no reliable statistical relationship in 2007.
• Models simulated similar vegetation water fluxes but differed in runoff and percolation.
• Higher evaporation demand on the SW-slope resulted in decreased overall water loss, not increased drought stress.

Conclusions:

• Hydrological models can effectively simulate soil water dynamics in beech forests.
• Beech stands on warmer slopes may conserve water by reducing overall system water loss.
• Findings have implications for understanding forest resilience to climate change and potential impacts on beech growth.