Natascha Kljun. Photo.

Natascha Kljun

Professor

Natascha Kljun. Photo.

The Net Landscape Carbon Balance—Integrating terrestrial and aquatic carbon fluxes in a managed boreal forest landscape in Sweden

Author

  • Jinshu Chi
  • Mats B. Nilsson
  • Hjalmar Laudon
  • Anders Lindroth
  • Jörgen Wallerman
  • Johan E.S. Fransson
  • Natascha Kljun
  • Tomas Lundmark
  • Mikaell Ottosson Löfvenius
  • Matthias Peichl

Summary, in English

The boreal biome exchanges large amounts of carbon (C) and greenhouse gases (GHGs) with the atmosphere and thus significantly affects the global climate. A managed boreal landscape consists of various sinks and sources of carbon dioxide (CO2), methane (CH4), and dissolved organic and inorganic carbon (DOC and DIC) across forests, mires, lakes, and streams. Due to the spatial heterogeneity, large uncertainties exist regarding the net landscape carbon balance (NLCB). In this study, we compiled terrestrial and aquatic fluxes of CO2, CH4, DOC, DIC, and harvested C obtained from tall-tower eddy covariance measurements, stream monitoring, and remote sensing of biomass stocks for an entire boreal catchment (~68 km2) in Sweden to estimate the NLCB across the land–water–atmosphere continuum. Our results showed that this managed boreal forest landscape was a net C sink (NLCB = 39 g C m−2 year−1) with the landscape–atmosphere CO2 exchange being the dominant component, followed by the C export via harvest and streams. Accounting for the global warming potential of CH4, the landscape was a GHG sink of 237 g CO2-eq m−2 year−1, thus providing a climate-cooling effect. The CH4 flux contribution to the annual GHG budget increased from 0.6% during spring to 3.2% during winter. The aquatic C loss was most significant during spring contributing 8% to the annual NLCB. We further found that abiotic controls (e.g., air temperature and incoming radiation) regulated the temporal variability of the NLCB whereas land cover types (e.g., mire vs. forest) and management practices (e.g., clear-cutting) determined their spatial variability. Our study advocates the need for integrating terrestrial and aquatic fluxes at the landscape scale based on tall-tower eddy covariance measurements combined with biomass stock and stream monitoring to develop a holistic understanding of the NLCB of managed boreal forest landscapes and to better evaluate their potential for mitigating climate change.

Department/s

  • Dept of Physical Geography and Ecosystem Science
  • BECC - Biodiversity and Ecosystem services in a Changing Climate
  • Centre for Environmental and Climate Science (CEC)
  • MERGE - ModElling the Regional and Global Earth system

Publishing year

2020-04

Language

English

Pages

2353-2367

Publication/Series

Global Change Biology

Volume

26

Issue

4

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Climate Research
  • Forest Science

Keywords

  • boreal forest landscape
  • catchment stream monitoring
  • greenhouse gas fluxes
  • land cover heterogeneity
  • net landscape carbon balance
  • tall-tower eddy covariance
  • terrestrial and aquatic carbon fluxes

Status

Published

ISBN/ISSN/Other

  • ISSN: 1354-1013