I recently made a visit to Shenzhen in SubTropical Southern China.
The city core has a well-established grid of tree-lined streets with separate traffic lanes for vehicles, bicycles and pedestrians demarcated by trees and tropical greenery. The tree canopies overlap, providing continuous street level shade, just as I have advocated for the past twenty+ years in climate-based urban design guidelines.
Check out this program from ABC Radio National “The Money” that backs this assertion up with interviews from some top researchers and landscape architects covering the positive effect of street trees on quality of urban life, property values, and pollution abatement and removal. The bottom line is that the benefits of large street trees outweigh the costs of maintaining them.