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| Titel |
Can intra-annual stable isotope signals in tree-ring cellulose be used to extend Fluxnet data-model analysis to larger temporal and spatial scales? |
| VerfasserIn |
J. Ogée, L. Wingate, J. Jouanguy, D. Bert, C. Lambrot, M. Devaux, M. Stievenard, M. Pierre, D. Loustau, P. Berbigier |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021034
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| Zusammenfassung |
| Long-term eddy covariance measurements of CO2 and water fluxes are essential
to validate forest ecosystem models. However, to test these models and improve
our predictions over larger forested areas or longer time frames, complementary
datasets are required. In this respect, high-resolution intra-annual measurements
of the carbon and oxygen stable isotope composition of cellulose in annual tree
rings (δ13Ccelluloseand δ18Ocellulose, respectively) may provide a solution. This is
because well-defined seasonal patterns of plant carbon and water dynamics are
recorded in the tree ring cellulose over the growing season in response to climatic
variability. We explored this potential by collecting a 10-year, high-resolution cellulose
dataset from maritime pine trees growing in the flux tower footprint at Le Bray.
To link these isotopic tree-ring signals to the continuous 10-year record of flux
measurements a simple, single-substrate model describing wood growth and isotopic
discrimination was used. Over this decade seasonal patterns of the observed δ13Ccelluloseand
δ18Ocellulose exhibited strong year-to-year variability. This novel dataset was then
compared against model simulations of δ13Ccelluloseand δ18Ocellulose and a sensitivity
analysis to the main parameters and climate variables was performed to identify
which aspects of the model were best constrained by the isotopic chronologies. |
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