References of "Vesala, T"
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See detailExperimental evaluation of flux footprint by natural tracer experiment
Arriga, N.; Aubinet, Marc ULg; Carrara, A. et al

Poster (2009, April)

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See detailExceptional Carbon Uptake In European Forests During The Warm Spring Of 2007: A Data-Model Analysis
Delpierre, N.; Soudani, K.; Kostner, B. et al

in Global Change Biology (2009), 15(6), 1455-1474

Temperate and boreal forests undergo drastic functional changes in the springtime, shifting within a few weeks from net carbon (C) sources to net C sinks. Most of these changes are mediated by temperature ... [more ▼]

Temperate and boreal forests undergo drastic functional changes in the springtime, shifting within a few weeks from net carbon (C) sources to net C sinks. Most of these changes are mediated by temperature. The autumn 2006-winter 2007 record warm period was followed by an exceptionally warm spring in Europe, making spring 2007 a good candidate for advances in the onset of the photosynthetically active period. An analysis of a decade of eddy covariance data from six European forests stands, which encompass a wide range of functional types (broadleaf evergreen, broadleaf deciduous, needleleaf evergreen) and a wide latitudinal band (from 44 degrees to 62 degrees N), revealed exceptional fluxes during spring 2007. Gross primary productivity (GPP) of spring 2007 was the maximum recorded in the decade examined for all sites but a Mediterranean evergreen forest (with a +40 to +130 gC m(-2) anomaly compared with the decadal mean over the January-May period). Total ecosystem respiration (TER) was also promoted during spring 2007, though less anomalous than GPP (with a +17 to +93 gC m(-2) anomaly over 5 months), leading to higher net uptake than the long-term mean at all sites (+12 to +79 gC m(-2) anomaly over 5 months). A correlative analysis relating springtime C fluxes to simple phenological indices suggested spring C uptake and temperatures to be related. The CASTANEA process-based model was used to disentangle the seasonality of climatic drivers (incoming radiation, air and soil temperatures) and biological drivers (canopy dynamics, thermal acclimation of photosynthesis to low temperatures) on spring C fluxes along the latitudinal gradient. A sensitivity analysis of model simulations evidenced the roles of (i) an exceptional early budburst combined with elevated air temperature in deciduous sites, and (ii) an early relief of winter thermal acclimation in coniferous sites for the promotion of 2007 spring assimilation. [less ▲]

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See detailCO2 balance of boreal, temperate, and tropical forests derived from a global database
Luyssaert, S.; Inglima, I.; Jung, M. et al

in Global Change Biology (2007), 13(12), 2509-2537

Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this ... [more ▼]

Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome-specific carbon budgets; to re-examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 degrees C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome-specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non-CO2 carbon fluxes are not presently being adequately accounted for. [less ▲]

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See detailReduction Of Ecosystem Productivity And Respiration During The European Summer 2003 Climate Anomaly: A Joint Flux Tower, Remote Sensing And Modelling Analysis
Reichstein, M.; Ciais, P.; Papale, D. et al

in Global Change Biology (2007), 13(3),

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See detailTowards A Standardized Processing Of Net Ecosystem Exchange Measured With Eddy Covariance Technique: Algorithms And Uncertainty Estimation
Papale, D.; Reichstein, M.; Aubinet, Marc ULg et al

in Biogeosciences (2006), 3(4),

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See detailQuality Analysis Applied On Eddy Covariance Measurements At Complex Forest Sites Using Footprint Modelling
Rebmann, C.; Gockede, M.; Foken, T. et al

in Theoretical and Applied Climatology (2005), 80(2-4),

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See detailEurope-Wide Reduction In Primary Productivity Caused By The Heat And Drought In 2003
Ciais, P.; Reichstein, M.; Viovy, N. et al

in Nature (2005), 437(7058),

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See detailCarbon balance gradient in European forests: should we doubt 'surprising' results? A reply to Piovesan & Adams
Jarvis, P. G.; Dolman, A. J.; Schulze, E. D. et al

in Journal of Vegetation Science (2001), 12(1), 145-150

This paper responds to the Forum contribution by Piovesan & Adams (2000) who criticized the results obtained by the EUROFLUX network on carbon fluxes of several European forests. The major point of ... [more ▼]

This paper responds to the Forum contribution by Piovesan & Adams (2000) who criticized the results obtained by the EUROFLUX network on carbon fluxes of several European forests. The major point of criticism was that the data provided by EUROFLUX are inconsistent with current scientific understanding. It is argued that understanding the terrestrial global carbon cycle requires more than simply restating what was known previously, and that Piovesan & Adams have not been able to show any major conflicts between our findings and ecosystem or atmospheric-transport theories. [less ▲]

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See detailGap Filling Strategies For Long Term Energy Flux Data Sets
Falge, E.; Baldocchi, D.; Olson, R. et al

in Agricultural and Forest Meteorology (2001), 107(1),

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See detailGap Filling Strategies For Defensible Annual Sums Of Net Ecosystem Exchange
Falge, E.; Baldocchi, D.; Olson, R. et al

in Agricultural and Forest Meteorology (2001), 107(1),

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See detailProductivity Overshadows Temperature In Determining Soil And Ecosystem Respiration Across European Forests
Janssens, Ia.; Lankreijer, H.; Matteucci, G. et al

in Global Change Biology (2001), 7(3),

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See detailFootprint Analysis For Measurements Over A Heterogeneous Forest
Rannik, U.; Aubinet, Marc ULg; Kurbanmuradov, O. et al

in Boundary-Layer Meteorology (2000), 97(1),

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See detailRespiration As The Main Determinant Of Carbon Balance In European Forests
Valentini, R.; Matteucci, G.; Dolman, Aj. et al

in Nature (2000), 404(6780),

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See detailEstimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology.
Aubinet, Marc ULg; Grelle, A.; Ibrom, A. et al

in Advances in Ecological Research (1999), 30

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See detailNew estimate of the carbon sink strength of EU forests integrating flux measurements, field surveys, and space observations: 0.17-0.35 Gt(C)
Martin, Philippe; Valentini, R.; Jacques, M. et al

in AMBIO : A Journal of the Human Environment (1998), 27(7), 582-584

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