Best Time to Open/Carve an Old Wound - Japanese Maple?

[MrBonsai19]

I recently acquired this Japanese Maple. I am not sure which cultivar it is, but I am inclined to believe it is *not* a pure-strain acer palmatum.





There is an old wound on the trunk that needs to be re-carved to heal flush and I am wondering what is the best time of year to re-open this wound and proceed with a fresh concave cut. I have seen some sources that now is a good time, but other suggestions that bleeding and sap-loss could be a risk and that post leaf-drop in the Fall is better when the sap is receding is better. Other suggestions that best time is in the early Spring as long as you repot the tree and work the roots, sap loss would not be an issue.

Welcome thoughts and input from all; I am planning to work on the more conservative side in terms of choosing the ideal timing since it is a new tree for me and I am not sure exactly how strong it is. So I am leaning toward waiting until the Fall leaf-drop pruning window, but at the same time it would be kind of nice to get started on healing this year since it will take a long time to heal this wound.

Thanks!

PS - What is the best tool to remove liquid cut paste? I used a utility pick and caused a fair bit of damage :/

 

[BobbyLane]

If the plan is to 're open' a wound, so that callus can begin forming again, then I'd do that during the active growth period.

 

[Dav4]

Yup, I’d do it now.

 

[MrBonsai19]

Appreciate the feedback… I’ll give it a shot and maybe share some updates here

 

[WNC Bonsai]

I’d undercut the surface so that when the bark regrows it will be flush. Some have reported that covering the wound with aluminum foil will give a smoother surface and heal faster but I have not had the opportunity to try it.

 

[MrBonsai19]

I went for the wound clean up on the lowest portion of the trunk. I want to do similar work on the scars near the apex but it would require removing branches/leaves so I decided not to do those now. It might be negligible but I’d rather let the tree get as much strength this year. I will most likely carve and prune back all the branches right after leaf drop.

Appreciate the input!