Improving the ecological benefits evaluation on urban street trees: Development of a living vegetation volume quantifying framework with multi-source data

The rate of urbanization is increasing, and solutions to the pollution issue are desperately needed. Urban street trees are an essential factor in improving the environmental quality of cities. Quantifying precise ecological benefits of individual trees is important for monitoring urban ecology. However, since street tree surveys are time-consuming and expensive, it is challenging to assess the ecological benefits of street trees. Besides, there is still a need for more investigation into the advantages of multi-source data for ecological benefits estimates. Effective living vegetation volume (eLVV) as an urban green space indicator is beneficial for providing the vertical structure of street trees and offering a possibility for estimating the ecological benefits. The objective of this study is to evaluate the accurate ecological benefits of street trees by calculating eLVV. We developed and validated a framework for evaluating the ecological benefits of urban vegetation using point cloud and image processing techniques. Terrestrial laser scanning and unmanned aerial vehicle data were used to predict indicators at the single tree scale and road scale. Models based on game theory were applied to score all the indicators and assess the ecological benefits. The results showed that: (1) The proposed framework demonstrated that multi-source data allowed for the exact indicators of ecological benefits. (2) The eLVV of the street trees on two roads was less on the north side than on the south side, reflecting the difference in the ecology of the street trees in terms of orientation. This paper explores the advantages of multi-source data in measuring detailed ecological benefits, which support the digital management of street trees and the sustainability of regional ecology.