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

Chi, Jinshu ; Nilsson, Mats B. ; Laudon, Hjalmar ; Lindroth, Anders LU ; Wallerman, Jörgen ; Fransson, Johan E.S. ; Kljun, Natascha LU ; Lundmark, Tomas ; Ottosson Löfvenius, Mikaell and Peichl, Matthias (2020) In Global Change Biology 26(4). p.2353-2367
Abstract

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... (More)

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.

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; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
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
in
Global Change Biology
volume
26
issue
4
pages
15 pages
publisher
Wiley-Blackwell
external identifiers
  • pmid:31912589
  • scopus:85079448770
ISSN
1354-1013
DOI
10.1111/gcb.14983
language
English
LU publication?
yes
id
58ec9c06-352b-4a05-9e66-37af937f5bb8
date added to LUP
2020-02-27 08:44:38
date last changed
2021-03-03 05:48:19
@article{58ec9c06-352b-4a05-9e66-37af937f5bb8,
  abstract     = {<p>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 (CO<sub>2</sub>), methane (CH<sub>4</sub>), 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 CO<sub>2</sub>, CH<sub>4</sub>, 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 km<sup>2</sup>) 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<sup>−2</sup> year<sup>−1</sup>) with the landscape–atmosphere CO<sub>2</sub> exchange being the dominant component, followed by the C export via harvest and streams. Accounting for the global warming potential of CH<sub>4</sub>, the landscape was a GHG sink of 237 g CO<sub>2</sub>-eq m<sup>−2</sup> year<sup>−1</sup>, thus providing a climate-cooling effect. The CH<sub>4</sub> 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.</p>},
  author       = {Chi, Jinshu and Nilsson, Mats B. and Laudon, Hjalmar and Lindroth, Anders and Wallerman, Jörgen and Fransson, Johan E.S. and Kljun, Natascha and Lundmark, Tomas and Ottosson Löfvenius, Mikaell and Peichl, Matthias},
  issn         = {1354-1013},
  language     = {eng},
  number       = {4},
  pages        = {2353--2367},
  publisher    = {Wiley-Blackwell},
  series       = {Global Change Biology},
  title        = {The Net Landscape Carbon Balance—Integrating terrestrial and aquatic carbon fluxes in a managed boreal forest landscape in Sweden},
  url          = {http://dx.doi.org/10.1111/gcb.14983},
  doi          = {10.1111/gcb.14983},
  volume       = {26},
  year         = {2020},
}