The primary purposes of pruning is to select which buds will form shoots for the upcoming harvest and to prepare the vine for the fruiting process in harvests in the future. Pruning can also help control the number of buds, which has a direct effect on the yield of a vine, another factor that can affect the quality of the wine. In Europe, the pruning method is often controlled by law.
There are two types of pruning-- spur and cane. In spur pruning, several short spurs are left on the vine. In cane pruning, one or two canes are left, each with 8-15 buds.