Assessing Heat Stress Tolerance of Native and Exotic Urban Planted Tree Species Under Future Climate Scenarios in New York City

Abstract

Urban street trees provide critical ecosystem services including shade, air purification, and cooling, yet their capacity to persist under accelerating climate change remains poorly understood. Building on the foundational framework of Kullberg et al. (2024), who demonstrated widespread thermal vulnerability among urban trees in Miami, this study extends that methodology to evaluate New York City's urban forest across 435 street tree species representing over 700,000 individual trees in all five boroughs. Thermal safety margins, the buffer between a species' physiological heat tolerance and the maximum temperatures it experiences, are currently positive for the majority of NYC's street trees, but face rapidly narrowing buffers as temperatures rise through the century under the most extreme warming scenarios. Initial results suggest that significant proportion of the entire urban forest projected to exceed species-level thermal limits by 2100, with exotic European species already under stress today.