Mitigation of CO2 Emissions Based on Above Ground Biomass Assessment in Tropical Regions (Case Study: Gresik City, East Java, Indonesia)

Indonesia is a tropical region experiencing rapid industrial growth. Gresik City is located in East Java Province, Indonesia, and is recognized as an industrial area with major activities including nickel and steel smelting, electronics, petrochemicals, and energy production. Sukorejo and Gulomantung villages in Gresik City are coastal areas with residential conditions surrounded by industries. Industrial and residential activities in Sukorejo and Gulomantung villages emit CO2 emissions, which can enhance the greenhouse effect. One of the initial steps in controlling greenhouse gases is through the assessment of aboveground biomass and the calculation of carbon stocks. This study estimates carbon stocks from vegetation in Sukorejo and Gulomantung villages to absorb CO2 emissions from industrial and residential activities in June to August 2023. Calculation of CO2 emissions uses data on energy consumption and electricity usage from industrial and residential sources. CO2 emissions are estimated absorbed by vegetation using allometric carbon calculation equations. Calculation of carbon stocks is based on aboveground biomass (AGB) of vegetation. The estimation of AGB is conducted using allometric equations based on wood density and diameter at breast height (DBH). The research findings indicate that the total CO2 emissions from industrial and residential sources in the villages of Sukorejo and Gulomantung amount to 165 196.14 tons/year. The carbon stock in Sukorejo and Gulomantung total 2871.74 tons/ha with a CO2 absorption capacity of 22 403.68 tons/year, resulting in 142 792.46 tons/year of unabsorbed CO2. Increasing the planting of large shade trees in Gulomantung is necessary due to the availability of extensive vacant land. This study concludes with two optimal scenarios: scenario 1 involves adding one tree species, while scenario 2 consists of a combination of six large shade tree species.