## 4 Conclusions  
This study indicates that cluster-zone leaf removal is an effective method for reducing acidity and significantly influences the composition of phenolic and volatile compounds in berries. The removal of cluster-zone leaves at the hard green berry stage, before and after veraison, generally increased the content of anthocyanins and flavonoids, thereby improving the quality of the colour of the berries. The effect of cluster-zone leaf removal on the aroma of Cabernet Sauvignon grapes is twofold. The collective evidence from two years of experimentation suggests that early leaf removal increases the content of bound terpen while decreasing norisoprenoid levels. This may be related to the reduction in neoxanthin content, the precursor of \(\beta\)-damascenone, which has a significant impact on the fruity aroma of the grape berry. Additionally, early leaf removal may also promote the transformation of C6/C9 aldehydes into alcohols, as well as a decrease in free-form terpen. However, these findings were only observed in a single year and require further validation. As for Marselan grapes, leaf removal increases the levels of C6/C9 aldehydes but has limited effects on terpen and norisoprenoids. These findings indicate that leaf removal after veraison can enhance the colour of Cabernet Sauvignon grapes without adversely affecting the quality of their aroma. In the case of Marselan grapes, leaf removal at the hard green berry stage can result in the highest concentration of anthocyanins and flavonoids without affecting the aroma of the berries. However, it should be noted that our study on Marselan grapes was conducted only over one year, and thus the effects of leaf removal on Marselan grapes still require further examination.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/plants13111543/1](https://www.mdpi.com/article/10.3390/plants13111543/1)]([https://www.mdpi.com/article/10.3390/plants13111543/1](https://www.mdpi.com/article/10.3390/plants13111543/1)), Table S1: Weather conditions in the vineyard during different phenological stages from 2021 to 2022; Table S2: Composition of flavan-3-ols (mg/kg FW) in Cabernet Sauvignon and Marselan grapes at different stages of leaf-removal treatment from 2021 to 2022; Table S3: Composition of aromatic compounds (\(\mu\)g/kg) in Cabernet Sauvignon and Marselan grapes at different stages of leaf-removal treatment from 2021 to 2022.  
Conceptualization, C.D. and Q.P.; methodology, X.Y. and Y.L.; software, X.Y.; validation, X.Y.; formal analysis, X.Y.; investigation, X.Y., Y.W., Y.L., Y.C. and T.S.; resources, Y.C. and T.S.; data curation, X.Y.; writing--original draft preparation, X.Y.; writing--review and editing, C.D. and Q.P.; visualization, X.Y. and Y.W.; supervision, C.D. and Q.P.; funding acquisition, Q.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Earmarked Fund for China Agriculture Research System (CARS-29), the Hebei Province Industrial Innovation and Entrepreneurship Team project (215A7602D) and the Science and Technology Cooperation Project between China Agricultural University and Bodega Langes Co., Ltd.  
Data Availability Statement: Data are contained within the article or Supplementary Materials.  
The author sincerely thanked Bodega Langes Co., Ltd. for the help on experimental implementation and grape sampling.  
**Conflicts of Interest**: Authors [PERSON] and [PERSON] were employed by the company Bodega Langes Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from Bodega Langes Co., Ltd. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.