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Contributions of climate, leaf area index and leaf physiology to variation in gross primary production of six coniferous forests across Europe: a model-based analysis

Duursma, R. A.; Kolari, P.; Peramaki, M.; Pulkkinen, M.; Makela, A.; Nikinmaa, E.; Hari, P.; Aurela, M.; Berbigier, P. and Bernhofer, Ch., et al. (2009) In Tree Physiology 29(5). p.621-639
Abstract
Gross primary production (GPP) is the primary source of all carbon fluxes in the ecosystem. Understanding, variation in this flux is vital to understanding variation in the carbon sink of forest ecosystems, and this would serve as input to forest production models. Using GPP derived from eddy-covariance (EC) Measurements, it is now possible to determine the most important factor to scale GPP across sites. We use long-term EC measurements for six coniferous forest stands in Europe, for a total of 25 site-years, located oil a gradient between Southern France and northern Finland. Eddy-derived GPP varied threefold across the six sites, peak ecosystem leaf area index (LAI) (all-sided) varied from 4 to 22 m(2) m(-2) and mean annual temperature... (More)
Gross primary production (GPP) is the primary source of all carbon fluxes in the ecosystem. Understanding, variation in this flux is vital to understanding variation in the carbon sink of forest ecosystems, and this would serve as input to forest production models. Using GPP derived from eddy-covariance (EC) Measurements, it is now possible to determine the most important factor to scale GPP across sites. We use long-term EC measurements for six coniferous forest stands in Europe, for a total of 25 site-years, located oil a gradient between Southern France and northern Finland. Eddy-derived GPP varied threefold across the six sites, peak ecosystem leaf area index (LAI) (all-sided) varied from 4 to 22 m(2) m(-2) and mean annual temperature varied from - 1 to 13 degrees C. A process-based model operating at a half-hourly time-step was parameterized with available information for each site, and explained 71-96% in variation between daily totals of GPP within site-years and 62% of annual total GPP across site-years. Using the parameterized model, we performed two simulation experiments: weather datasets were interchanged between sites, so that the model was used to predict GPP at some site using data from either a different year or a different site. The resulting bias in GPP prediction was related to several aggregated weather variables and was found to be closely related to the change in the effective temperature sum or mean annual temperature. High R(2)s resulted even when using weather datasets from unrelated sites, providing a cautionary note on the interpretation of R-2 ill model comparisons. A second experiment interchanged stand-structure information between sites. and the resulting bias was strongly related to the difference in LAI, or the difference in integrated absorbed light. Across the six sites. variation in mean annual temperature had more effect on simulated GPP than the variation in LAI. but both were important determinants of GPP. A sensitivity analysis of leaf physiology parameters showed that the quantum yield was the most influential parameter on annual GPP, followed by a parameter controlling the seasonality of photosynthesis and photosynthetic capacity. Overall, the results are promising for the development of a parsimonious model of GPP. (Less)
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publication status
published
subject
keywords
process-based model, forest carbon uptake, forest productivity
in
Tree Physiology
volume
29
issue
5
pages
621 - 639
publisher
Oxford University Press
external identifiers
  • wos:000265850500001
  • scopus:67649883174
ISSN
1758-4469
DOI
10.1093/treephys/tpp010
language
English
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yes
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5ef31100-7765-4822-b013-b7a5dd11b5bc (old id 1426281)
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2009-06-30 12:00:07
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2017-01-01 05:44:12
@article{5ef31100-7765-4822-b013-b7a5dd11b5bc,
  abstract     = {Gross primary production (GPP) is the primary source of all carbon fluxes in the ecosystem. Understanding, variation in this flux is vital to understanding variation in the carbon sink of forest ecosystems, and this would serve as input to forest production models. Using GPP derived from eddy-covariance (EC) Measurements, it is now possible to determine the most important factor to scale GPP across sites. We use long-term EC measurements for six coniferous forest stands in Europe, for a total of 25 site-years, located oil a gradient between Southern France and northern Finland. Eddy-derived GPP varied threefold across the six sites, peak ecosystem leaf area index (LAI) (all-sided) varied from 4 to 22 m(2) m(-2) and mean annual temperature varied from - 1 to 13 degrees C. A process-based model operating at a half-hourly time-step was parameterized with available information for each site, and explained 71-96% in variation between daily totals of GPP within site-years and 62% of annual total GPP across site-years. Using the parameterized model, we performed two simulation experiments: weather datasets were interchanged between sites, so that the model was used to predict GPP at some site using data from either a different year or a different site. The resulting bias in GPP prediction was related to several aggregated weather variables and was found to be closely related to the change in the effective temperature sum or mean annual temperature. High R(2)s resulted even when using weather datasets from unrelated sites, providing a cautionary note on the interpretation of R-2 ill model comparisons. A second experiment interchanged stand-structure information between sites. and the resulting bias was strongly related to the difference in LAI, or the difference in integrated absorbed light. Across the six sites. variation in mean annual temperature had more effect on simulated GPP than the variation in LAI. but both were important determinants of GPP. A sensitivity analysis of leaf physiology parameters showed that the quantum yield was the most influential parameter on annual GPP, followed by a parameter controlling the seasonality of photosynthesis and photosynthetic capacity. Overall, the results are promising for the development of a parsimonious model of GPP.},
  author       = {Duursma, R. A. and Kolari, P. and Peramaki, M. and Pulkkinen, M. and Makela, A. and Nikinmaa, E. and Hari, P. and Aurela, M. and Berbigier, P. and Bernhofer, Ch. and Grunwald, T. and Loustau, D. and Mölder, Meelis and Verbeeck, H. and Vesala, T.},
  issn         = {1758-4469},
  keyword      = {process-based model,forest carbon uptake,forest productivity},
  language     = {eng},
  number       = {5},
  pages        = {621--639},
  publisher    = {Oxford University Press},
  series       = {Tree Physiology},
  title        = {Contributions of climate, leaf area index and leaf physiology to variation in gross primary production of six coniferous forests across Europe: a model-based analysis},
  url          = {http://dx.doi.org/10.1093/treephys/tpp010},
  volume       = {29},
  year         = {2009},
}