Code for Environmental and biotic controls on water use efficiencies of urban street trees

To evaluate the water use efficiencies of urban street trees, we measured stable carbon isotope ratio (δ13C) of 634 leaf samples (including 315 samples for healthy trees and 309 samples for unhealthy trees) within the central urban areas of 14 large cities across China. We then calculated iWUEs via a stable carbon isotope approach and explored the characteristics of iWUEs in urban street trees and their large-scale patterns. Additionally, we complied data on two climate variables (i.e., MAP and mean maximum daily temperature), five anthropogenic variables (e.g., PM2.5, O3, SO2, NO2, and road width), and nine biotic variables (i.e., diameter at breast height, unhealthiness grade of leaf size, leaf abundance, and leaf color as well as tree trunk damage and tree branch damage, life form, phylogeny types, and mycorrhiza types) and explored the key drivers in shaping the large-scale patterns of urban street tree iWUEs.