Assessing urban CO2 emissions and sequestration potential: a case study of median strip trees in Baghdad

Abstract

Rapid population growth has led to increased concentrations of greenhouse gases, particularly carbon dioxide (CO₂), which contributes to rising temperatures. Trees are one of the most important tools for achieving carbon neutrality in cities. This study aims to evaluate the ability of trees planted in the median strip of Palestine Street in Baghdad to sequester CO₂ from vehicle traffic emissions, using the Carbon Sequestration Index (CSI). A traffic survey was conducted on weekdays and holidays, with daily averages of 100,015 and 60,009 vehicles. Estimated annual emissions were 11,970,241.66 kg/year, with a strong correlation between the number of vehicles and emissions (r = 0.91). The field tree survey included 103 individuals of four species, and annual sequestration was calculated based on their physical characteristics, amounting to only 3198.8 kg/year, reflecting a low CSI (0.000267). To address this imbalance, a scenario was proposed to improve afforestation by utilizing 182 unused tree pits and planting highly sequestration species. This resulted in a 176.7% increase in tree number and an additional sequestration of 874.6 kg/year of CO₂. The results confirm the importance of quantitative analysis in supporting urban vegetation planning decisions and promoting environmental sustainability in cities with high traffic density.