Data from: Contrasting heat tolerance of evergreen and deciduous urban woody species during heat waves

The increasing frequency and intensity of heat waves caused significant
damages to urban woody species, and the different leaf structures between
evergreen and deciduous species may be closely related to leaf heat
tolerance. However, whether the different leaf structural traits of
evergreen and deciduous plants contribute to their different responses
under heat waves is still unclear. During the record-breaking and
long-lasting 2022 summer heat waves in China, we investigated the
relationships between leaf thermal indices and leaf structural traits of
36 urban woody species in four cities along the Yangtze River. We found
that all the four thermal indices were significantly but weakly related
with leaf damage status. The critical temperature that causes the initial
15% damage to photosystem II (Tcrit) may serve as a sensitive measure of
heat tolerance. Evergreen species suffered less leaf damage during the
heat waves and exhibited higher leaf heat tolerance, thicker leaves than
deciduous species. Tcrit was significantly correlated with leaf mass per
area, leaf thickness and thickness of spongy tissue. Synthesis: Urban
woody species with high Tcrit, leaf mass per area, and leaf thickness tend
to be more tolerant to heat stress. This study provides insights for
predicting leaf heat tolerance of urban woody plants in subtropical China
and their physiological and ecological responses to severe heat waves.