Original Research Papers
Biophysical controls on CO2 fluxes of three Northern forests based on long-term eddy covariance data
Authors:
Fredrik Lagergren ,
Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, SE
Anders Lindroth,
Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, SE
Ebba Dellwik,
Risø National Laboratory, Wind Energy Department, Technical University of Denmark, DK
Andreas Ibrom,
Risø National Laboratory, Biosystems Department, Technical University of Denmark, DK
Harry Lankreijer,
Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, SE
Samuli Launiainen,
Department of Physical Sciences, University of Helsinki, Helsinki, FI
Meelis Mölder,
Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, SE
Pasi Kolari,
Department of Forest Ecology, University of Helsinki, Helsinki, FI
Kim Pilegaard,
Risø National Laboratory, Biosystems Department, Technical University of Denmark, DK
Timo Vesala
Department of Physical Sciences, University of Helsinki, Helsinki, FI
Abstract
Six to nine years of net ecosystem carbon exchange (NEE) data from forests in Hyytiälä in Finland, Sorø in Denmark and Norunda in Sweden were used to evaluate the interannual variation in the carbon balance. For half-monthly periods, average NEE was calculated for the night-time data. For the daytime data parameters were extracted for the relationship to photosynthetic active radiation (PAR). The standard deviation of the parameters was highest for Norunda where it typically was around 25% of the mean, while it was ca. 15% for Hyytiälä and Sorø. Temperature was the main controller of respiration and photosynthetic capacity in autumn, winter and spring but explained very little of the interannual variation in summer. A strong correlation between respiration and photosynthesis was also revealed. The start, end and length of the growing season were estimated by four different criteria. The start date could explain some of the variation in yearly total NEE and gross primary productivity (GPP) in Hyytiälä and Sorø, but the average maximum photosynthetic capacity in summer explained more of the variation in annual GPP for all sites than start, end or length of the growing season.
How to Cite:
Lagergren, F., Lindroth, A., Dellwik, E., Ibrom, A., Lankreijer, H., Launiainen, S., Mölder, M., Kolari, P., Pilegaard, K. and Vesala, T., 2008. Biophysical controls on CO2 fluxes of three Northern forests based on long-term eddy covariance data. Tellus B: Chemical and Physical Meteorology, 60(2), pp.143–152. DOI: http://doi.org/10.1111/j.1600-0889.2007.00324.x
Published on
01 Jan 2008.
Peer Reviewed
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