The national law in Indonesia stated that cities are required to have 30% of green open space from the total area. Tangerang City is one of the capital's buffer cities that has been continuously grown since the 1990s. The development of the city is quite rapid, and the emergence of various activities such as household activities, transportation, and industry are encouraging changes in green open space areas. Data from the regional statistic shows that open green space in Tangerang City is only 12.56% (2,319.21 hectares) of the total area. The less open green space area might degrade its main function as an absorber of emissions or pollutants, especially for carbon dioxide gas (CO2). This study aims to estimate the biomass, total CO2 stored by vegetation. This study uses direct measurements and vegetation index to formulate the ideal biomass formula. The pre-field activities begin with the extraction of NDVI (Normalized Differential Vegetation Index) and EVI (Enhanced Vegetation Index) from SPOT 7 imageries. The biomass allometric formulas used in this study are the Brown and Lugo equation, to find biomass values from tree stand parameters such as diameter breast height (DBH) and tree height. Quantitative and spatial analysis used in this study is a regression analysis of biomass and vegetation index value. The results show EVI has a better regression value and total biomass of around 26 million kilograms.