Green Space Ecosystem Services and Value Evaluation of Three-Dimensional Roads for Sustainable Cities

The provision of green space as a result of three-dimensional roads plays a crucial role in maintaining the sustainability of the urban ecosystem. It does so by solving environmental problems and offering various ecosystem services to city residents. This study focuses on the park section of an expressway located between Bundang and Suseo in Seongnam city, South Korea, and quantifies the improvement in air quality and ecological value following the transformation of the road into green infrastructure. The goal is to determine the feasibility of sustainable green infrastructure for roads. The new park area on the road is approximately 83,000 sq. meters and there are approximately 3349 trees planted in the park. These trees can store 77.68 metric tons of carbon annually, isolate 13.21 metric tons of total carbon, remove 70.446 kg of air pollutants, avoid 112.8 cubic meters of emissions, and mitigate 31,983.90 cubic feet of emissions. The resulting economic value is approximately 874,494 dollars. Road green infrastructure conversion can be a useful solution to respond to environmental problems. To promote decision-making when developing policies, a process of pre-verification with quantified data of ecosystem services (example: air quality benefits, etc.) of trees using the i-Tree Eco program is required. In the execution stage, it is possible to understand the structure, function, and value of green spaces and prepare guidelines for tree selection, design alternatives, and evaluation as one of the management strategies for green spaces to improve the value of ecosystem services