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 deciduou..., Quantify leaf damage status (LDR, Fv/Fm)：
(1) Leaf damage ratio (LDR). To quantify physical leaf tissue damage caused by heat waves, we visually assessed and recorded the percentage of damaged leaves in the entire plant canopy as LDR following Esperon-Rodriguez et al. (2021). Specifically, burned areas on the leaf surface associated with a color change from green to light brown with dark brown margins were considered as leaf damage. Two fixed people scored the LDR of each tree, and if their results were similar (within 10% difference), the average value was taken. If the results differed greatly, a third evaluator was asked to provide more information to achieve a more accurate value. We evaluated five replicates per species, and the final average was taken to represent the LDR.
(2) The maximum quantum efficiency (Fv/Fm) of the leaf photosystem II. We sampled 3-5 individuals per species, collected over twenty leaves for each individual (totally 60-100 leaves per species), and brought th..., , # Contrasting heat tolerance of evergreen and deciduous urban woody species during heat waves

[https://doi.org/10.5061/dryad.7pvmcvf23](https://doi.org/10.5061/dryad.7pvmcvf23)

We have submitted our raw data (Data.xls). There are two sheets in the “Data” table.

**MetaData** lists the paper title, abbreviation of all the names of each column in the RawData

**RawData** is the raw data; any missing values are shown as \"NA\" to minimize ambiguity.

## Description of the data and file structure

### Data:

* Species: Scientific name of the species
* City: Study sites

* Leafhabit: evergreen and deciduous

* EHF: Excess heat factor

* LDR: Leaf damage ratio (%)

* Fv/Fm: The maximum quantum efficiency of the leaf photosystem II (unitless)

* Tleafmax: The maximum temperature of leaf during the day (°C)

* Tcrit : The critical temperature causes the initial damage (15%) to Fv/Fm (°C)

* T50: The temperature causes 50% damage to Fv/Fm (°C)

* TSMcrit: The ...