Work

Ecosystem Water-Use Efficiency in a Warm-Temperate Evergreen Broad-Leaved Forest in the Republic of Korea

Year: 2026

Type: article

Abstract: Warm-temperate evergreen broad-leaved forests are distinguished from the deciduous broad-leaved forests in that their foliage is retained year-round and their specific leaf area is often higher than that of temperate evergreen coniferous forests. However, the implications of these traits for carbon and water fluxes and their coupling remain poorly understood. In this study, we quantified gross primary production (GPP), evapotranspiration (ET), water-use efficiency (WUE), and intrinsic WUE (IWUE) using seven years of eddy-covariance measurements from a warm-temperate evergreen broad-leaved forest in southern South Korea. We further evaluated the abiotic and biotic drivers of their seasonal variability using structural equation modeling. The forest acted as a carbon sink even during winter, with an annual GPP of 2176 ± 135 g C m−2 yr−1, ET of 596 ± 59 kg H2O m−2 yr−1, a mean daily WUE of 4.15 ± 0.25 g C (kg H2O)−1, and a mean daily IWUE of 20.3 ± 3.0 g C hPa (kg H2O)−1. Among WUE components, the main driver of GPP during warm and humid periods was incoming shortwave radiation (RSDN) followed by air temperature (Tair), whereas ET was primarily controlled by Tair. Cold and dry seasons and main annual drivers of GPP and ET were Tair. Although the leaf area index (LAI) was increased by RSDN and Tair, it did not serve as a mediator affecting GPP and ET, contrary to our expectations. Differences in how GPP and ET responded to abiotic factors ultimately governed WUE and IWUE in this forest type, underscoring the importance of site-specific characteristics in evaluating ecosystem water-use efficiency.

Source: Water

DOI: 10.3390/w18030354

Authors: Hyunyoung Yang, A Reum Kim, Jung-Hwa Chun

Institution: National Institute of Forestry Science

Language: English

Topic: Plant Water Relations and Carbon Dynamics

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,137