TY - JOUR
T1 - Gross primary productivity in duke forest
T2 - Modeling synthesis of co2 experiment and eddy-flux data
AU - Luo, Yiqi
AU - Medlyn, Belinda
AU - Hui, Dafeng
AU - Ellsworth, David
AU - Reynolds, James
AU - Katul, Gabriel
PY - 2001
Y1 - 2001
N2 - This study was designed to estimate gross primary productivity (GPP) in the Duke Forest at both ambient and elevated CO2 (ambient + 200 μL/L) concentrations using a physiologically based canopy model. The model stratified the canopy of loblolly pine (Pinus taeda L.) forest into six layers and estimated photosynthesis in each layer according to the Farquhar submodel coupled with the Ball-Berry stomatal conductance submodel. The model was parameterized with a suite of physiological measurements, including leaf area index (LAI), leaf nitrogen (N) concentration, photosynthesis-N relationships, and stomatal conductance. The model was validated against measured leaf photosynthesis and canopy carbon (C) fluxes estimated from eddy-covariance measurements (ECM). Application of this model to simulate canopy C fixation from 28 August 1996, the onset of CO2 fumigation, to 31 December 1998 suggested that elevation of atmospheric [CO2] to ambient + 200 μL/L resulted in increase of canopy C fixation by 35% in 1996. 39% in 1997, and 43% in 1998. The modeled GPP and its response to elevated [CO2] were sensitive to parameter values of quantum yield of electron transport, leaf area index, and the vertical distribution of LAI within the canopy. Thus, further investigation on those parameters will help improve the precision of estimated ecosystem-scale C fluxes. Furthermore, comparison between the modeled and ECM-estimated canopy C fluxes suggested that soil moisture, in addition to air vapor pressure, controlled canopy photosynthesis during the drought period.
AB - This study was designed to estimate gross primary productivity (GPP) in the Duke Forest at both ambient and elevated CO2 (ambient + 200 μL/L) concentrations using a physiologically based canopy model. The model stratified the canopy of loblolly pine (Pinus taeda L.) forest into six layers and estimated photosynthesis in each layer according to the Farquhar submodel coupled with the Ball-Berry stomatal conductance submodel. The model was parameterized with a suite of physiological measurements, including leaf area index (LAI), leaf nitrogen (N) concentration, photosynthesis-N relationships, and stomatal conductance. The model was validated against measured leaf photosynthesis and canopy carbon (C) fluxes estimated from eddy-covariance measurements (ECM). Application of this model to simulate canopy C fixation from 28 August 1996, the onset of CO2 fumigation, to 31 December 1998 suggested that elevation of atmospheric [CO2] to ambient + 200 μL/L resulted in increase of canopy C fixation by 35% in 1996. 39% in 1997, and 43% in 1998. The modeled GPP and its response to elevated [CO2] were sensitive to parameter values of quantum yield of electron transport, leaf area index, and the vertical distribution of LAI within the canopy. Thus, further investigation on those parameters will help improve the precision of estimated ecosystem-scale C fluxes. Furthermore, comparison between the modeled and ECM-estimated canopy C fluxes suggested that soil moisture, in addition to air vapor pressure, controlled canopy photosynthesis during the drought period.
KW - Canopy
KW - Carbon sink or sequestration
KW - Duke Forest
KW - Forest
KW - Global change
KW - Gross primary productivity (GPP)
KW - Loblolly pine
KW - Model
KW - Modeling
KW - North Carolina (USA)
KW - Photosynthesis
KW - Pinus taeda
KW - Stomatal conductance
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U2 - 10.1890/1051-0761(2001)011[0239:gppidf]2.0.co;2
DO - 10.1890/1051-0761(2001)011[0239:gppidf]2.0.co;2
M3 - Article
AN - SCOPUS:0035147670
SN - 1051-0761
VL - 11
SP - 239
EP - 252
JO - Ecological Applications
JF - Ecological Applications
IS - 1
ER -