Drought shortens subtropical understory growing season by advancing leaf senescence

Subtropical forests, recognized for their intricate vertical canopy stratification, exhibit high resistance to extreme drought. However, the response of leaf phenology to drought in the species-rich understory remains poorly understood. In this study, we constructed a digital camera system, amassing over 360,000 images through a 70% throughfall exclusion experiment, to explore the drought response of understory leaf phenology. The results revealed a significant advancement in understory leaf senescence phenology under drought, with 11.75 and 15.76 days for the start and end of the leaf-falling event, respectively. Pre-season temperature primarily regulated leaf development phenology, whereas soil water dominated the variability in leaf senescence phenology. Under drought conditions, temperature sensitivities for the end of leaf emergence decreased from -13.72 days ℃-1 to -11.06 days ℃-1, with insignificance observed for the start of leaf emergence. Consequently, drought treatment shorte..., We constructed a digital camera system to monitor understory leaf phenology within a throughfall exclusion experiment in a subtropical forest. The start of leaf emergence, end of leaf emergence, start of leaf falling, and end of leaf falling of understory were extracted. Subsequently, The length of growing season and length of peak growth were calculated. Simultaneously, pertinent climatic variables were recorded. Additional methodological details can be found in the “Materials and methods” section of the article., , # Drought shortens subtropical understory growing season by advancing leaf senescence

[https://doi.org/10.5061/dryad.fn2z34v3d](https://doi.org/10.5061/dryad.fn2z34v3d)

We utilized a digital camera system in conjunction with a throughfall exclusion experiment to examine the impact of drought on subtropical understory leaf phenology. Our findings revealed a notable advancement in understory leaf senescence phenology, with an insignificant shift observed in leaf development phenology under experimental drought conditions, ultimately leading to a shortened growing season.

## Description of the data and file structure

Table 1. Daily understory normalized GCC (Green Chromatic Coordinates) in the throughfall exclusion experiment at plot-scale from 2017 to 2022

Table 2. Daily understory normalized GCC in the throughfall exclusion experiment at species-scale

Table 3. Understory leaf phenology in the throughfall exclusion experiment at plot-scale from 2017 to 2022

Table 4. The leaf phenol...