Daily and Annual CO2 Uptake of Pterocarpus macrocarpus and Azadirachta siamensis under Field Condition

Abstract

The green areas are generally taken into account for building projects and the city planning. Annual CO₂ uptake obtained by the field measurement, followed by the mathematical model can be used to calculate the green area. Hence, this study investigated values of daily and annual CO₂ uptake by two plant species, Pterocarpus macrocarpus and Azadirachta siamensis. The experimental results showed that average daytime CO₂ uptake rates were significantly higher for A. siamensis than P. macrocarpus in August and December. The monthly daytime CO₂ uptake showed the highest value in December of 69.05 gC m^-2 for P. macrocarpus and 89.27 gC m^-2 for A. siamensis. For the monthly nighttime CO₂ release, the highest value was in March of 24.40 gC m^-2 for P. macrocarpus and 26.66 gC m^-2 for A. siamensis. The annual estimations in daytime CO₂ uptake, nighttime CO₂ release and net CO₂ uptake for P. macrocarpus were 641.69 gC m^-2, 259.06 gC m^-2 and 382.63 gC m^-2, respectively. For A. siamensis, the annual estimations in daytime CO₂ uptake, nighttime CO₂ release and net CO₂ uptake were 773.66 gC m^-2, 286.43 gC m^-2 and 487.23 gC m^-2, respectively.