Carbon flux extraction for a Phyllostachys violascens ecosystem based on the flux footprint analysis

Abstract

This study was conducted to explain distribution of the flux source area and the spatial representation of flux measurements for mixed Phyllostachys violascens （Lei bamboo） and non-Lei bamboo stands in Taihuyuan. Based on the Flux Source Area Model （FSAM）, footprint and source area functions were calculated using the continuous flux measurement with the open-path eddy covariance system for the full-year of 2013. Carbon fluxes, according to the area occupied and the contribution of Lei and non-Lei bamboo stands, were separated from the measured eddy covariance flux measurement values to determine the monthly average carbon fluxes using the flux footprint analysis. Results showed that the area responsible for 90% of the surface influence was about 2.0 km 2.0 km and was centered at the flux observation tower. Few differences were noted in flux source area at the four cardinal directions; however, the flux source area was much greater in atmospheric conditions that were stable （having a range of 96.19－941.63 m） compared to unstable （with a range of 28.62－313.54 m）. After separation of Lei and non-Lei bamboo stands, the total net carbon sequestration of the Lei bamboo ecosystem was 4.25 thm－2a－1, and when the underlying surface consisted of non-Ph. violascens stands, it was 6.65 thm－2a－1. Without separation, using the eddy covariance measurements as the Lei bamboo ecosystem flux value, total net sequestration was 5.46 thm－2a－1. This research could help with more accurate evaluations of carbon sequestration capacity in a Lei bamboo ecosystem. ［Ch, 4 fig. 4 tab. 29 ref.］