Vitisphere By Marion Bazireau On February 24, 2025

 Numerous observations by winegrowers support the importance of following the principles of respectful pruning, but very little research has validated the interest of not disturbing the sap path. At the Teclimpro day held in Bordeaux on 18 February, Spanish viticulture professor Luis Gonzaga Santesteban came to present the results of a comparative study conducted by the University of Pamplona in two newly planted Tempranillo plots and therefore free from the influence of previous pruning practices.

The two plots were formed in a bilateral cordon respecting the same stages of foot formation. In each of them, three types of pruning were compared: a so-called "respectful" pruning, for which the cuts were always made on the same side, leaving a stub greater than 1.5 times the diameter of the cut wood; so-called "aggressive" pruning, for which the sap paths were not followed and no snags were left; and an "intermediate" pruning, corresponding to the common practices of Navarre winegrowers who do not refrain from making the cuts on opposite sides of the arm and leave on average a stub of 0.7 to 1 times the diameter of the cut wood. These three sizes were applied to five stages of the CEP formation process, in December 2019, May 2020, and December 2020, 2021 and 2022.

To compare the effects of the techniques, Luis Gonzaga Santesteban and his team measured the cross-sectional area of the wood, the weight of the branches removed during green pruning, and the weight of wood from winter pruning. Unsurprisingly, vines pruned in a "respectful" manner almost always showed significantly higher growth values for these three indicators, reflecting better physiological condition. The differences were particularly marked in the less vigorous vineyard. The trial, on the other hand, did not show any major differences between vines pruned in an "aggressive" way and vines pruned according to the winegrowers' habits.

Luis Gonzaga Santesteban imagines that these results would be the same in an adult vineyard and has set up new trials to verify this.

photo credit: Adobe Stock