Why should cuttings for grafting fruit trees be harvested in winter?

In order to successfully plant a fruit tree and get tasty fruits, the harvesting of cuttings for grafting must be done in winter. This is due to the fact that cuttings harvested at the beginning of winter, before the onset of severe frosts, are in the so-called “sleeping mode”. In addition, they will not have time to freeze in severe frosts, which increases the chance of successful plant grafting.