Flush cut vs stub cut

[The Warm Canuck]

So, I've been searching this site and reading different resources and I can't figure out when to flush cut and when to leave a stub, when cutting a branch? Some insight would be much appreciated.

 

[Rivian]

Depends on the species and who you ask. There is also a third option, concave cuts.

 

[Shibui]

Also depends on who you ask as many have little practical experience.
For me, flush cut is when I don't need any new shoots from that location. Leave a stub to allow for new buds in case I need a branch or trunk extension from that point.
Occasionally stubs are left when I know the species dies back a bit after a chop. Allows for die back to the required point then cleaned the following year.

 

[The Warm Canuck]

Depends on the species and who you ask. There is also a third option, concave cuts.

I should be more clear, when flush cutting I mean using concave cuts.

 

[The Warm Canuck]

Also depends on who you ask as many have little practical experience.
For me, flush cut is when I don't need any new shoots from that location. Leave a stub to allow for new buds in case I need a branch or trunk extension from that point.
Occasionally stubs are left when I know the species dies back a bit after a chop. Allows for die back to the required point then cleaned the following year.

Does size matter? say a 1/2" branch vs 1" branch.

Or branch vs sacrifice trunk cop?

Do your same principles apply?

Could someone list some brief examples of common species that die back vs those that don't?

 

[BonjourBonsai]

examples of common species that die back vs those that don't?

From experience, Acer palmatum and pinus mugo die back.

 

[shinmai]

From my experience, about 54% of the population believes that size matters.

 

[The Warm Canuck]

From my experience, about 54% of the population believes that size matters.

Every partner I've been with says size doesn't matter. I've always wondered why they feel compelled to tell me that

 

[invaderzim]

I'm interested in this discussion from the standpoint of scarring/wound healing as well. I'm just a beginner so please feel free to correct me if I'm wrong. My particular aesthetic preference is for for very minimal scarring. Just in regards to the type of cut being made and not taking into account other things you can do to promote better healing, my understanding is that cutting to the branch collar and therefore leaving a small stub followed by cutting flush (not concave) at a later date generally produces better healing of scars because of die back/wound compartmentalization. But I've also seen that instead of the flush cut, a concave cut is better as the scar can sometimes add a bulge. I guess my question is how you determine whether a flush cut or concave cut is more appropriate? Or is there clearly one that's better than the other?

 

[Shibui]

Does size matter? say a 1/2" branch vs 1" branch.

Or branch vs sacrifice trunk cop?

Do your same principles apply?

Size does alter things but I don't think it is as simple as defined measurements. I probably take relative size into account - 1/2" branch on a 3" trunk is different to a 1/2" branch on a 3/4" trunk for example when it comes to die back and scarring as the cuts heal. The larger the cut is compared to the trunk/branch it is on the more pronounced the scar can become.

I generally don't bother much with any cuts under 1/4" diameter. They'll usually heal over without much effort.

I don't think I make any allowances for difference between branch cut or trunk chop.

Japanese maple is probably the species I have experienced die back after pruning more than any other.

I'm interested in this discussion from the standpoint of scarring/wound healing as well. I'm just a beginner so please feel free to correct me if I'm wrong. My particular aesthetic preference is for for very minimal scarring. Just in regards to the type of cut being made and not taking into account other things you can do to promote better healing, my understanding is that cutting to the branch collar and therefore leaving a small stub followed by cutting flush (not concave) at a later date generally produces better healing of scars because of die back/wound compartmentalization. But I've also seen that instead of the flush cut, a concave cut is better as the scar can sometimes add a bulge. I guess my question is how you determine whether a flush cut or concave cut is more appropriate? Or is there clearly one that's better than the other?

I find it difficult to reconcile the new 'natural target' pruning - leaving branch collars - with the way we have pruned bonsai for hundreds of years. Bonsai are mostly pruned well behind the branch collars to avoid lumpy scars. They don't seem to suffer as a result.
Concave cuts definitely heal flatter and neater than a flat cut or leaving the collar intact.
The larger the cut the deeper the concave cut seems to need to be to get final closure flush with the rest of the trunk.