Work

Variability of evapotranspiration fluxes affected by dry and wet year transitions in beech, pine and mixed stands in the lowland of northeast Germany

Year: 2025

Type: article

Abstract: • EcH 2 O model effectively captures variations in ecohydrological fluxes. • P is the most important driver for interannual variations of ET. • P legacy effects buffer ET reductions during the 2018 drought. • Broadleaf species (e.g., beech) promote groundwater recharge and water management. Increasing climate variability, especially prolonged droughts, shapes forest water consumption and constrains vegetation growth. However, the effects of drought-induced changes on evapotranspiration (ET) fluxes vary due to species-specific differences and drought characteristics. Here, we analyzed the seasonal variations in ET in pine, beech, and mixed forest stands in northeast Germany (2012–2021) and explored the ability of a process-based ecohydrological model (EcH 2 O) in reproducing the water balance components observed at three forested lysimeters. To better understand how individual climate variables control ET fluxes, we performed simulation experiments with detrended climate inputs. Multi-variable calibration showed that the model reproduced well in-situ soil moisture, seepage, and interception (EI) in the three stands. Precipitation (P) was the main driver of ET anomalies, with above-average ET in wet years and below-average ET in dry years. However, only small reductions in ET were observed during the dry year 2018. This could be attributed to high P in the previous year, i.e., P legacy effects, which led to only small reductions or even positive anomalies in ET. The beech stand, with a seasonal leaf cycle, had lower ET and interception losses compared to the pine and mixed stands, which maintain year-round foliage. This resulted in greater percolation to deeper soil layers in beech forests. These findings suggest that broadleaf species such as beech by allowing greater water transfer to groundwater, offer a distinct hydrological advantage in terms of promoting deep percolation. Our results therefore provide a process-based rationale for the strategic selection of broadleaf species in forest management to enhance groundwater recharge and promote sustainable water management. Additionally, model testing at such data-rich sites will be valuable for improving the process-consistency and reliability of other hydrological models, particularly in studies aimed at investigating the effects of different vegetation cover.

Source: Agricultural and Forest Meteorology

DOI: 10.1016/j.agrformet.2025.110771

Authors: Yeye Liu, Marco Natkhin, Doris Duethmann

Institutions: Chinese Academy of Sciences, Institute of Subtropical Agriculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Johann Heinrich von Thünen-Institut

Language: English

Topic: Plant Water Relations and Carbon Dynamics

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDGs: Climate action, Life on land

Open Access status: hybrid

Estimated APC paid: $3,590