Funny, just had a question from a club member today about when is the best time to repot/prune Malus (apple, crab apple).
Don't have a definite opinion, but from conversations on French forums a couple of years ago:
After leaf fall, there is still some sap activity. Pruning in autumn usually means more dormant buds to appear, which I find logical: the energy that is still produced, instead of being dispatched on a branch with say 3,4,5... internodes will concentrate lower down. Like all living beings, a tree "wants" to survive, so it will produce more buds on a section that was pruned.
Think of trees that can be cut down leaving no branches, like you can do with an elm or a zelkova that you want to style as a "broom" (hokidachi). : new buds will form at the cut. It's the same kind of logics. Or when you defoliate a Ficus : the best chance to have it backbud is to cut off the tip of the branches, otherwise all the energy will only allow the branch to grow further.
A crappy Zelkova I planted in the ground instaed of binning it, 3 years later (still a crappy Zelkova, but it just shows it works

):
It might sound off-topic, but I think it's relevant, it is related to the cultivation/cycle of trees and how to understand, or at least pay attention to, how it works so that we do the right thing at the right time according to the goal pursued
