prunning is to reduce the ramifications of the vine to control its natural growth improving crop yield and quality of the fruit, for the upcoming harvest.
Afterharvest , the vine starts a vegetative dormency. Leaves start to fall because the sap (formed by water and nutrients) is concentrating in the woody parts and goes down to the roots, process needed for the plant to survive winter.
This labour is carried out by the viticulturist, in vineyards that have started their winter dormancy, when the weather conditions allow to do the cuts of the prunning with the minimum risk of infections or drying of the vines.
Prunning entails laborious work and it is done by specialized personel because it is one of the most important jobs at the vineyards of Rioja since from its good execution will depend upon the quality of the grapes obtained later on.