The best time to remove the wire applied in the fall

[minkes]

In the fall I wired several hornbeams. When is the best time to remove the wire? Just before budding or wait when the tree starts to grow until the wire gently starts to cut into the bark?

 

[gschup]

You remove it when it starts biting in. Too early and the branches might spring back, too late and you get scars.

Also important that you can remove wire only on parts of the tree where it actually bites in, not everywhere at once.

 

[Wires_Guy_wires]

You kind of don't want it to bite in on deciduous because the scars will show up for decades - or sometimes never even go away.
You remove it before it starts biting in. If needed, re-apply it. Some people even wrap their wire in softer material to prevent biting in.
I personally don't like unwiring trees with dormant buds because I easily knock them off. If there's active growth, removing the wire is more difficult but the healing of damage is way faster.

But keep in mind that even though wood solidifies a bit in winter, it does most of the good settling during a growing season. Which is why I don't meddle a lot in deciduous plants; it takes a lot of active attention during active seasons and I want to give my plants a bit of privacy under their canopy.