Biomass estimates from urban green space in Bekasi City using Sentinel imageries

Abstract

The establishment of urban green spaces is essential for reducing climate change and global warming impacts in the urban ecosystem. Rapid expansion from the Jakarta's megapolitan is influencing Bekasi City and further leads to the massive conversion of urban green space into built-up areas. The land cover changes are affecting biomass and carbon sequestration capability of urban green space towards emissions from anthropogenic activities. Monitoring efforts through biomass estimation is important for a better understanding of the benefits of urban green spaces. Therefore, the goals of this study are to examine the best vegetation index used for interpreting urban green space, and analyze the spatial distribution of biomass. This study used Sentinel-2B satellite imageries acquired in 2020, and further employ them to generate four vegetation index, NDVI, GNDVI, SAVI, and OSAVI. The calculation of stand tree biomass was carried out by field measurements and allometric equations developed by the United States Department of Agriculture (USDA). Biomass estimation models developed from the relation between vegetation index and the observed biomass value The results of this study was that the best vegetation index was OSAVI with an accuracy rate of 99 %. The biomass produced in this study was 0.10149 tons/grid or 101.49 kg/grid to 1.913 tons/grid or 1913.99 kg. Bekasi dominated the low biomass value, while the value of biomass was more dominant in the Bekasi City Forest area. This research is expected to be an input for the local government, and the findings will become base information for maintaining urban green space in the city.