Understanding urban tree heat and drought stress

This study was conducted at an urban site in western Sydney, Australia to determine why certain urban trees were vulnerable to severe water stress and hydraulic failure. We measured environmental variables (i.e., soil volumetric water content, percentage of impervious surfaces), tree physiology (predawn and midday leaf water potential, maximum quantum yield of photosystem II), and growth of 19 urban tree species (n=3-10 trees per species) from 2019‒2023, spanning the extreme and subsequent three wet summers. Data are reported for individual trees (n=118 trees, including 28 stressed trees).