Rongfei's talk at the American Geophysical Union fall meeting 2025

Rongfei’s abstract: Urban trees play a critical role in buffering residents from the combined effects of climate warming and urban heat islands (UHI). However, the cooling benefits they provide are not distributed equitably within cities, particularly in socioeconomically disadvantaged neighborhoods shaped by legacies of segregation and disinvestment. In this study, we ask how do tree species composition and functional diversity influence cooling efficiency, and to what extent are these benefits distributed unevenly within and across U.S. cities. We hypothesized that higher tree species richness and functional diversity enhance local cooling effects; and neighborhoods with lower socioeconomic status receive less overall cooling, yet exhibit stronger marginal gains in cooling efficiency per unit increase in biodiversity. To test these hypotheses, we combined ground-based urban tree inventories with remotely sensed land surface temperature (LST) across 215 U.S. cities from 2020 to 2024. We found that neighborhoods with lower socioeconomic indicators tend to have significantly lower tree species and poor functions (e.g., tree height, basal area, biomass, and wood volume) than more fluent areas. Despite this disparity, increasing tree species richness led to nearly twice the cooling benefit in lower-income neighborhoods compared to wealthier ones. These findings suggest that while urban tree diversity generally improves thermal regulation, its effectiveness and distribution are modulated by socio-economic factors. Our work highlights the importance of incorporating species-level and trait-based metrics into urban greening strategies.