Urban Forests and Carbon Sequestration

Both rapid urbanization and carbon dioxide (CO2) emissions substantially contribute to climate change. Carbon dioxide is the most frequently released greenhouse gas by humans. The built environment, which includes activities like cooking, urban transit, and building heating, is mostly to blame for this. The results show an inverted U-shaped relationship between CO2 emissions and urbanization. Several factors, including transportation density and atmospheric stability, influence the concentration of near-surface CO2 in cities. Urban forests are essential for maintaining the basic biological and environmental services that cities offer for the survival of people, animals, and plants as the world's cities become increasingly urbanized. Because plants can sequester CO2 through photosynthesis, they can store carbon in the soil and plant biomass. Cities’ green spaces may significantly influence local atmospheric CO2 concentrations, as seen by comparisons between urban and rural areas, which show lower CO2 concentrations in the presence of vegetation. The amount of CO2 sequestered over the “urban forest” varies throughout the growth season, with nighttime emissions in response to respiration and absorption taking place during the day when plants are photosynthetically active. Increased atmospheric CO2 concentrations stimulate more efficient photosynthesis in plants by acting as a fertilizer. However, the photosynthetic system of urban plants is regularly hampered by environmental stresses, which, in extreme conditions, can lead plants to switch from being carbon sinks to carbon sources. The many functions, benefits, and advantages that urban woods provide are essential to the sustainable development of metropolitan regions. This chapter analyzed the most recent studies to understand better the roles that urban trees play today and in the future in removing CO2 from the atmosphere, and we highlight the need for more study.