Calculation and Optimization of the Carbon Sink Benefits of Green Space Plants in Residential Areas: A Case Study of Suojin Village in Nanjing

Objectives: In the “dual evaluation” of land space, the evaluation of the importance of ecosystem service functions and residential areas is important, playing a significant role in plants acting as carbon sinks and thereby achieving the transformation of low-carbon settlements. Methods: The paper compares and analyzes five models for quantifying carbon sink benefits and focuses on the national tree benefit calculator (NTBC) model, which is suitable for the carbon sequestration benefits of plants in residential areas, to (i) estimate and compare the economic benefits brought by trees and shrubs in residential areas, (ii) analyze the reasons for the differences between the current data and data for the next 20 years, and (iii) comprehensively evaluate the technical points related to the plant landscape in residential areas to assess whether they comply with the “Green Settlement Standard.” The index system was scored according to the standard. Result: The current data collected for existing trees and shrubs include the following: When the trees are in good condition, the order of the trees according to their economic benefits in the current year is Zelkova serrata > Cedrus deodara > Sapindus saponaria > Sophora japonica > Cinnamomum camphora > Prunus cerasifera > Magnolia grandiflora > Ulmus pumila > Acer L. > Lagerstroemia indica L. > Sapium sebiferum > Sabina > Punica granatum L. > Acer palmatum > Sapium sebiferum > Celtis sinensis Pers > Bambusa multiplex > Cycas > Melia azedarach L. > Pinus parviflora, and that of the trees in the next 20 years is Zelkova serrata > Cinnamomum camphora > Sophora japonica > Sapindus saponaria > Ulmus pumila > Cedrus deodara > Prunus cerasifera > Magnolia grandiflora > Acer L. > Sapium sebiferum > Cycas > Punica granatum L. > Lagerstroemia indica L. > Acer palmatum Thunb > Sabina > Bambusa multiplex > Broussonetia papyrifera > Celtis sinensis Pers > Melia azedarach L. > Pinus parviflora. The order of shrubs according to their economic gain in the current year is Photinia beauverdiana > Pittosporum tobira > Ligustrum lucidum > Viburnum odoratissimum > Buxus cephalantha, and that of the shrubs in the next 20 years is Ligustrum lucidum > Photinia beauverdiana > Pittosporum tobira > Buxus cephalantha > Viburnum odoratissimum. Conclusion: Using plants, the construction ideas, community structure and landscape maintenance of the carbon sink estimation system of residential areas should be updated according to three aspects to promote the quantification of the carbon sink benefits of green areas in urban settlements and the development of low-carbon settlements in China.