## 5 Conclusions  
Flash droughs are one of the most complicated and catastrophic meteorological phenomena. In this study, we explored the complex dynamics of flash droughs occurringrapidly in the forest areas of northeastern China during the period from 2000 to 2020. Based on pentad soil moisture percentile criteria, we aimed to reveal findings regarding the number of flash drought events and their characteristics as well as their impacts on the forest NDVI. The main findings are summarized below:  
1. Our findings revealed the variability of flash drought events in three mountain areas, highlighting the significance of localized evaluations for successful drought mitigation strategies.
2. Although the total number of flash drought events was high, the repetition of events in the same location within our selected time frame was low and the total duration was not so prolonged, and there was not much distinct spatial variation in the flash drought characteristics among the three mountain areas.
3. The inter-annual variations in the area affected by flash drought events highlighted the changing interaction between climatic elements and the quick onset of drought conditions. The increasing trend in the NDVI during the decreasing trends in the flash drought, as well as the improvement in the NDVI value over the time period, revealed the negative impact of flash drought on the forest NDVI.  
The relation between flash drought and vegetation involves a complex interplay. Flash drought occurs rapidly within a short period of time, but its impact, especially on forest ecosystems, can be more severe. So, detailed analysis when studying and understanding the impacts of climatic phenomena like flash droughts on ecological systems by focusing on more specific area and time period requires further research. Our research emphasizes the necessity for specific drought mitigation strategies in the forests of northeastern China. Through the utilization of advanced methods, our findings are helpful in deeply understanding flash drought as well as its impact, contributing to more effective policy formulation and the enhancement of forest resilience.  
Conceptualization, B.L. and S.A.; methodology, S.A.; software, S.A. and W.Z.; formal analysis, S.A. and Z.D.; data curation, S.A., B.L. and W.Z.; writing--original draft preparation, S.A. and N.S; writing--review and editing, S.A., B.C., R.M. and B.L; visualization, S.A. and N.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 41877416.  
Not appliable.  
Not applicable.  
The soil moisture dataset referenced in this paper is available from the National Tibetan Plateau Data Center (TPDC) ([[http://www.tpdc.ac.cn/](http://www.tpdc.ac.cn/)]([http://www.tpdc.ac.cn/](http://www.tpdc.ac.cn/)), accessed on 3 September 2023). The NDVI dataset is available from the Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences ([[http://www.resdc.cn](http://www.resdc.cn)]([http://www.resdc.cn](http://www.resdc.cn)), assessed on 15 December 2023).  
The authors are grateful to the anonymous reviewers, the handling editor, and the editor-in-chief, whose comments were critical in finalizing the manuscript. We are filled with gratitude to [PERSON], [PERSON], [PERSON], [PERSON], and all the individuals who provided direct and indirect support at various stages of the study. The usual disclaimer applies, and all mistakes remain the authors' responsibility.  
The authors declare no conflicts of interest.