Analyzing the Impact of Leaf Removal Timing and Intensity as Adaptive Strategies for Climate Change on Burgundian Pinot Noir.

With the rise in global temperatures, the wine industry faces significant challenges in maintaining grape quality. Elevated sugar levels in grapes are leading to wines with higher alcohol content and reduced acidity, particularly in Burgundy, where such imbalances compromise the typicity of wines, clashing with traditional standards and consumer preferences. In response, the University of Burgundy engaged in a project from 2020 to 2023, on apical leaf removal as a strategy to mitigate the effects of climate change. This technique involves the removal of the uppermost leaves from grapevines, an action that aims to lower sugar content and water stress by reducing the leaf's transpiration area, all while preserving the grapes' essential acidity levels. This study encompassed experimental trials with Pinot Noir and Chardonnay grape varieties. It compared the impact of moderate and severe apical leaf removal, applied at two critical growth stages — bunch closure and 10 days after mid-veraison — against control groups with no leaf removal. The results revealed that severe apical leaf removal postponed mid-veraison by an average of 5 days and resulted in grapes with lower sugar and pH levels at harvest than those in the control group. This technique also led to more negative δ13C values, indicating a decrease in water stress in the vines. However, it concurrently resulted in reduced assimilable nitrogen and potential impacts on yield. Apical leaf removal emerges as a promising approach to producing high-quality grapes in an era of climatic change. Yet, further research is vital to optimize this method and fully understand its long-term impact on sustainable grape cultivation.