ibclogo XVI International Botanical Congess

Abstract Number: 2257
Poster No. = 2049


ELEVATED [CO2] INCREASES CANOPY C UPTAKE IN THE DUKE FOREST


Luo, Y., D. Hui, University of Oklahoma, USA, B. Medlyn, Station de Recherches Forestières, France, D. Ellsworth, Brookhaven National laboratory, USA, J. Reynolds, Duke University, USA.


This study utilizes a physiologically-based model to estimate canopy C uptake at ambient and elevated [CO2] in the Duke Forest, where a Free-Air CO2 Enrichment experiment has been in progress since August 1996. The model estimates photosynthesis according to Farquhar model in 6 canopy layers and was validated against measured diurnal courses of leaf photosynthesis and net ecosystem C exchange. Application of the model to simulate canopy C fixation from August 1996 to December 1998 suggested that elevated [CO2] resulted in a substantial increase in C influx into the forest ecosystem. The CO2 effect on forest canopy C uptake was found to be sensitive to possible acclimation in leaf area index, canopy nitrogen distribution, and leaf photosynthetic capacity.

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