Assessment of Urban Forest Ecological Benefit Based on the i-Tree Eco Model-A Case Study of Changchun Central City

Urban forests are one of the most ecologically significant systems in urban ecosystems. To make the layout and input-output ratio of urban forests more economically rational for sustainable strategic planning, it is necessary to assess the ecological benefits and ecosystem services of urban forests according to the local geographical characteristics of different cities and analyse their cost-benefit relationships. In this study, the i-Tree Eco model was used to assess the ecological benefits of urban forests in terms of four aspects: carbon sequestration and oxygen release, energy saving, rainwater retention, and air quality improvement. To translate them into economic benefits, using mathematical and statistical analysis, the cost-benefit relationship of urban forests with different tree and shrub proportions was analysed, and the impact range of urban forests with different layout types was compared. The research found that: (1) tree species are the main influencing factor of urban forest ecological benefits, (2) linear urban forests have a wider impact range, (3) if the proportion of trees in urban forests in the research area is adjusted to 0.36, the ecological benefits can increase by RMB 0.061 billion per year. We provide efficient and convenient research paths and tools for studying the cost-benefit relationship. By using an i-Tree Eco model, we realized the economic characteristics of urban forests. This research provides quantitative support for the balanced construction of urban ecological civilization and economic benefits. It can provide quantitative support for a balance between urban ecological development, economic development, and spatial optimization.