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Research article - Peer-reviewed, 2020

Partitioning growing season water balance within a forested boreal catchment using sap flux, eddy covariance, and a process-based model

Kozii, Nataliia; Haahti, Kersti; Tor-ngern, Pantana; Chi, Jinshu; Hasselquist, Eliza Maher; Laudon, Hjalmar; Launiainen, Samuli; Oren, Ram; Peichl, Matthias; Wallerman, Joergen; Hasselquist, Niles J.;

Abstract

Although it is well known that evapotranspiration (ET) represents an important water flux at local to global scales, few studies have quantified the magnitude and relative importance of ET and its individual flux components in high-latitude forests. In this study, we combined empirical sapflux, throughfall, and eddy-covariance measurements with estimates from a process-based model to partition the water balance in a northern boreal forested catchment. This study was conducted within the Krycklan catchment, which has a rich history of hydrological measurements, thereby providing us with the unique opportunity to compare the absolute and relative magnitudes of ET and its flux components to other water balance components. During the growing season, ET represented ca. 85 % of the incoming precipitation. Both empirical results and model estimates suggested that tree transpiration (T) and evaporation of intercepted water from the tree canopy (I-C) represented 43 % and 31 % of ET, respectively, and together were equal to ca. 70 % of incoming precipitation during the growing season. Understory evapotranspiration (ETu) was less important than T and I-C during most of the study period, except for late autumn, when ETu was the largest ET flux component. Overall, our study high-lights the importance of trees in regulating the water cycle of boreal catchments, implying that forest management impacts on stand structure as well as climate change effects on tree growth are likely to have large cascading effects on the way water moves through these forested landscapes.

Published in

Hydrology and Earth System Sciences

2020, volume: 24, number: 6, pages: 2999-3014
Publisher: COPERNICUS GESELLSCHAFT MBH

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Haahti, Kersti
Nat Resources Inst Finland Luke
Tor-ngern, Pantana
Chulalongkorn Univ
Chi, Jinshu
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Launiainen, Samuli
Natural Resources Institute Finland (LUKE)
Oren, Ram
Duke Univ
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Resource Management
Hasselquist, Niles
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management

Sustainable Development Goals

SDG13 Climate action

UKÄ Subject classification

Oceanography, Hydrology, Water Resources
Forest Science

Publication Identifiers

DOI: https://doi.org/10.5194/hess-24-2999-2020

URI (permanent link to this page)

https://res.slu.se/id/publ/106889