Defense Presentation Title: Does Chilling Explain the Divergent Response of Spring Phenology to Urban Heat Islands?

Advisor: Dr. Josh Gray, faculty fellow and associate professor in the Department of Forestry and Environmental Resources

Abstract: Understanding how temperature controls plant spring phenology, the timing of plants’ spring leaf development, is critical to studying the global carbon cycle and climate change. Urban heat islands (UHIs) could be a proxy for future climate warming and were thought to consistently advance urban plant spring phenology; however, observations found divergent phenological responses. To explore this phenomenon, my dissertation: (1) created a novel model to produce over 30 years of urban phenology data from satellite images; (2) evaluated a suite of methods to quantify temperature effects on spring phenology; and (3) investigated 80 US major cities to infer future spring phenological responses. Our results indicate that, despite current incomplete mechanistic understanding, spring phenology will likely keep advancing in the near future.