Cutting back air layer?

[Bnana]

Some time ago I made an air layer in a large Japanese Maple. About 90% of the branches above the air layer will be cut away.
I'm unsure about the timing. Should I do that now so the wounds can heal on the tree?
Wait till I remove the air layer so it can support the growth of roots? (but that's a lot of work at once for the tree)
Or let it establish in a pot first and cut back later?
I've read a lot on air layering but couldn't find how people do this.

 

[0soyoung]

Auxin, made primarily by the buds at the branch tips but also axillary buds and leaves, is required for root formation and growth. Carbohydrates, made by photosynthesis in the leaves, are the material to make new leaf tissue as well as being the energy source.

Given this, my conclusion is to keep all the foliage and branch tips to generate adventitious roots.

After harvesting the layer, the foliage then depends upon those adventitious roots. If you guessed incorrectly about how many new roots are enough when you harvested ...

Else, ...


Lastly, I think you will find that noticeable wounds won't heal over in just one season.

 

[Dav4]

Foliage is the engine that generates energy to grow new roots. Don't remove any foliage until the layer has grown enough roots to support it. When the layer is separated from the trunk, you may remove some of the unnecessary branching.

 

[Bnana]

I've left all foliage for that reason.
I'll remove a substantial part at separation than and the rest a year later.