Simulated soil CO<sub>2</sub> efflux and net ecosystem exchange 
in a 70-year-old Belgian Scots pine stand 
using the process model SECRETS

Sampson, David A.; Janssens, Ivan A.; Ceulemans, R.

doi:10.1051/forest:2001105

Cited by 34 publications

(39 citation statements)

References 35 publications

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“…Neither model performed very well when compared to the eddy covariance approach. It should be mentioned that the SECRETS model had been fine tuned and calibrated for the experimental forest site using the carbon pools and fluxes Sampson et al, 2001), but that no specific fine tuning or improved calibration was made with regard to the water fluxes.…”

Section: Four Methods To Assess (Evapo)transpiration: Strengths and Wmentioning

confidence: 99%

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Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Meiresonne

Sampson

Kowalski

et al. 2003

Journal of Hydrology

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Four distinct approaches, that vary markedly in the spatial and temporal resolution of their measurement and process-level outputs, are used to investigate the daily and seasonal water vapour exchange in a 70-year-old Belgian Scots pine forest. Transpiration, canopy interception, soil evaporation and evapotranspiration are simulated, using a stand-level process model (SECRETS) and a soil water balance model (WAVE). Simulated transpiration was compared with up-scaled sap flow measurements and simulated evapotranspiration to eddy covariance measurements.Reasonable agreement in the temporal trends and in the annual water balance between the two models was observed, however daily and weekly predictions often diverged. Most notably, WAVE estimated very low, to no transpiration during late autumn, winter and early spring when incident radiation fell below ,50 W m 22 while SECRETS simulated low (0.1-0.4 mm day 21 ) fluxes during the same period. Both models exhibited similar daily trends in simulated transpiration when compared with sap flow estimates, although simulations from SECRETS were more closely aligned. In contrast, WAVE over-estimated transpiration during periods of no rainfall and under-estimated transpiration during rainfall. Yearly, total evapotranspiration simulated by the models were similar, i.e. 658 mm (1997) and 632 mm (1998) for WAVE and 567 mm (1997) and 619 mm (1998) for SECRETS.Maximum weekly-average evapotranspiration for WAVE exceeded 5 mm day 21 , while SECRETS never exceeded 4 mm day 21 . Both models, in general, simulated higher evapotranspiration than that measured with the eddy covariance technique. An impact of the soil water content in the direct relationship between the models and the eddy covariance measurements was found.The results suggest that: (1) differentmodel formulations can reproduce similar results dependingon the scale at which outputs are resolved, (2) SECRETS estimates of transpiration were well correlated with the empirical measurements, and (3) neither model fitted favourably to the eddy covariance technique. q

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Section: Four Methods To Assess (Evapo)transpiration: Strengths and Wmentioning

confidence: 99%

“…The process model SECRETS is a sequential, multispecies and multi-structure simulator Sampson et al, 2001). It simulates stand scale carbon and water fluxes using established process algorithms adapted from several sources.…”

Section: Process-based Secrets Model (All Mathematical Equations Can mentioning

confidence: 99%

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Meiresonne

Sampson

Kowalski

et al. 2003

Journal of Hydrology

View full text Add to dashboard Cite

show abstract

“…Although most process-level outputs are available for these analyses we focused on the components of water balance that included canopy interception, evaporation, transpiration, throughfall, stem flow, and surface and soil water evaporation (all in units of mm d −1 ). A flow diagram of the model may be found in Sampson et al (2001).…”

Section: Secretsmentioning

confidence: 99%

“…The Stand to Ecosystem CaRbon and EvapoTranspiration Simulator (SECRETS) model was written to simulate standto ecosystem-scale carbon and water fluxes at this research site (Sampson et al, 2001). Accordingly, SECRETS can simulate multi-species multi-structured stands; stand-scale estimates of carbon and water fluxes may result from species dependent processes occurring in the over-story, sub-story, under-story or any combination of the three depending on the stand structure simulated.…”

Section: Secretsmentioning

confidence: 99%

Decadal water balance of a temperate Scots pine forest (<i>Pinus sylvestris</i> L.) based on measurements and modelling

et al. 2010

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Abstract. We examined the water balance components of an 80-year-old Scots pine (Pinus sylvestris L.) forest stand in the Campine region of Belgium over a ten year period using five very different approaches; our methods ranged from data intensive measurements to process model simulations. Specifically, we used the conservative ion method (CI), the Eddy Covariance technique (EC), an empirical model (WATBAL), and two process models that vary greatly in their temporal and spatial scaling, the ORCHIDEE global land-surface model and SECRETS a stand-to ecosystemscale biogeochemical process model. Herein we used the EC technique as a standard for the evapotranspiration (ET) estimates. Using and evaluating process based models with data is extremely useful as models are the primary method for integration of small-scale, process level phenomena into comprehensive description of forest stand or ecosystem function. Results demonstrated that the two process models corresponded well to the seasonal patterns and yearly totals of ET from the EC approach. However, both WATBAL and CI approaches overestimated ET when compared to the EC estimates. We found significant relationships between several meteorological variables (i.e., vapour pressure deficit [VPD], mean air temperature [T air ], and global radiation [Rg]) and ET on monthly basis for all approaches. In contrast, few relationships were significant on annual basis. Independent of the method examined, ET exhibited low inter-annual variability. Consequently, drainage fluxes were highly correlated with annual precipitation for all approaches examined, except CI.

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“…They are generally based on temperature-dependent relations [21,23,25,42], combined with soil moisture [9,11,13,16]. Most of the models that take into account temperature and soil moisture at the same time, assumed that the effects are multiplicative whereas some of them let vary the effect of temperature with soil moisture [9,37].…”

Section: Introductionmentioning

confidence: 99%

The key-role of topsoil moisture on CO₂ efflux from a Mediterranean Quercus ilex forest

et al. 2003

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-CO 2 respiratory losses partly determine net carbon ecosystem exchanges. The main objective of this paper was to understand regulation imposed by soil water content and temperature on soil and ecosystem CO 2 efflux in a holm oak (Quercus ilex L.) Mediterranean forest. Soil CO 2 efflux was monitored monthly during 1999 and 2001. Moreover, experimental water treatments were conducted in 1999 over 9 small plots (0.3 m 2 ) during nine months. Results showed strong decreases of soil CO 2 efflux for a relative soil water content below 0.7. Ecosystem respiration measured by eddy covariance over a 4-year period showed strong sensitivity to soil water content and temperature. Severe limitations of soil and ecosystem efflux imposed by low values of soil water content occurred on about 90 days per year. The best adjustments of soil and ecosystem CO 2 efflux were obtained using regression models where the exponential effect of temperature is linearly related to soil water content (r 2 = 0.68 and 0.79 for soil and ecosystem respectively). Our results highlighted strong differences in respiration sensitivity to topsoil moisture between soil and ecosystem. When the relative water content (RWC) is low (0.4), an increase of 1°C provokes an increase of soil respiration of 5.7% and an increase of ecosystem respiration of 8.6%. For nonlimiting soil water conditions, at RWC = 1, the increases of respiration caused by a 1°C temperature increase are of 8.5% and 16.5% for soil and ecosystem respectively. These results emphasized the probable determinant influences of changes in soil water regime for respiratory fluxes and net carbon exchanges of Mediterranean forest ecosystems.CO 2 efflux / soil water content / soil temperature / ecosystem respiration / Mediterranean ecosystem / Quercus ilex Résumé -Le rôle-clé de l'humidité du sol superficiel sur les efflux de CO 2 d'une forêt méditerranéenne de chêne vert. Les pertes de CO 2 par respiration vont déterminer largement les échanges nets de carbone des écosystèmes. L'objectif principal de cet article est de comprendre les régulations imposées par la teneur en eau et la température du sol sur les efflux de CO 2 du sol et de l'écosystème dans une forêt méditerranéenne de chêne vert (Quercus ilex L.). La respiration du sol a été mesurée mensuellement en 1999 et 2001. Par ailleurs, une expérimentation, mise en place en 1999, comprenant trois régimes hydriques a été suivie pendant 9 mois sur 9 parcelles de 0.3 m 2 . Les résultats mettent en évidence la très forte limitation des efflux lorsque la teneur en eau du sol est inférieure à 70 % de sa capacité de rétention. La respiration de l'écosystème mesurée sur une période de 4 ans par la méthode des fluctuations turbulentes montre la même sensibilité aux deux facteurs. Les conditions de fortes limitations par une faible teneur en eau du sol affectent l'écosystème environ 90 jours par an. Les meilleurs ajustements pour la simulation des flux de CO 2 du sol et de l'écosystème sont obtenus pour un modèle dans lequel l'effet exponentiel d...

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Simulated soil CO₂ efflux and net ecosystem exchange in a 70-year-old Belgian Scots pine stand using the process model SECRETS

Cited by 34 publications

References 35 publications

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Decadal water balance of a temperate Scots pine forest (<i>Pinus sylvestris</i> L.) based on measurements and modelling

The key-role of topsoil moisture on CO₂ efflux from a Mediterranean Quercus ilex forest

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Simulated soil CO2 efflux and net ecosystem exchange in a 70-year-old Belgian Scots pine stand using the process model SECRETS

Cited by 34 publications

References 35 publications

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Decadal water balance of a temperate Scots pine forest (&lt;i&gt;Pinus sylvestris&lt;/i&gt; L.) based on measurements and modelling

The key-role of topsoil moisture on CO2 efflux from a Mediterranean Quercus ilex forest

Contact Info

Product

Resources

About

Simulated soil CO₂ efflux and net ecosystem exchange in a 70-year-old Belgian Scots pine stand using the process model SECRETS

Decadal water balance of a temperate Scots pine forest (<i>Pinus sylvestris</i> L.) based on measurements and modelling

The key-role of topsoil moisture on CO₂ efflux from a Mediterranean Quercus ilex forest