The number of buds to be left on the vine at winter pruning should be judged relative to the vine’s capacity early in the growing season to support the growth of shoots. In turn, a balanced pruned vine will have sufficient shoot growth to ripen the fruit it carries. The amount of late-season growth is related to shoot growth early in the season. The amount of reserve, or stored, carbohydrates in the vine roots, trunk, and arms will determine how many developing shoots can be sustained. Of course, it is impossible to calculate the amount of stored reserves for each vine (which would involve excavation and chemical analysis), so dormant pruning weights are used as an indication. The underlying principle is that the more the amount of shoot growth in summer, the higher will be the pruning weight and also the stored carbohydrate reserves.