Urban green spaces are crucial for the exchange of energy fluxes, particularly sensible heat (QH) and latent heat (QE) fluxes. Therefore, this study aimed to investigate the characteristics of plant communities in urban green areas that affect turbulent fluxes, specifically QH and QE. The energy balance was measured using an eddy covariance system tower set up in three green areas at Kasetsart University: the Varunawan Garden (S1), the 100-Year Garden of Luang Suwan Vajokkasikit (S2), and the Phaholyothin Garden (S3). The results show that the canopy coverages of trees in S1, S2, and S3 were 526.23, 895.81, and 756.70 m2, respectively. The Bowen ratios (QH/QE) during the daytime in S1, S2, and S3 were 1.75, 1.09, and 1.43, respectively. These relationships suggest that dense trees, a dense canopy layer top, and the presence of water sources within the green areas resulted in a higher latent heat flux and a lower proportion of sensible heat flux. The findings of this study can be used as a guideline for the development and improvement of plant community structures in green areas within urban climate change adaptation.
Integrating green spaces into urban designs and planning for ecosystem services has become vital; however, in creating these spaces, the growth phase is often overlooked. This study provides insight into the changing energy and carbon dioxide (CO2) fluxes in a developing forest, “The Forestias” project in Thailand. The eddy covariance technique was applied to determine real-time surface energies and CO2 fluxes from December 2021 to September 2023. The results suggest that under fast growing conditions of the green areas, the diurnal latent energy flux corresponded with the area gained. This effect was supported by increasing evapotranspiration through the byproduct of canopy gas exchange. Consequently, the influence of green areas on lowering the average ambient temperature compared with the urban non-green surroundings was observed. In terms of CO2 flux dynamics, the increasing efficacy of photosynthesis was parallel with the growing forest canopy. Changes in flux dynamics due to urban green areas show their potential as a mitigation tool for moderating ambient air temperatures. Moreover, they can serve as a carbon sink within tropical cities and provide a pivotal contribution in reaching carbon neutrality.