CODIT in large diameter wood

[Boomslang]

Hoping for some confirmation, clarification, or further information here. I was told that in large cuts (>30cm/12in) CODIT was non-responsive or ineffective and therefore making the pruning cut at the branch collar wasn't totally necessary. Obviously you still don't want to flush cut, but being slightly inside or outside the collar was fine since the wound wouldn't heal over anyway.

Anecdotally, I've noticed many larger cuts I have seen did not seal over, but is there scientific backing to this.

 

[JD3000]

Pretty accurate, you will get a wound wood "donut" response in most cases but the issue is the high % of heart or ripewood exposed to decay organisms. This wood is chemically resistant to many, but not all, decay fungi, and results will vary by species,location, state of vitality, etc

 

[KTSmith]

JD is right (of course), but I think what both of them are referring to is wound closure rather than CODIT boundaries.
True, everything else being equal, a larger wound will take longer to close than a smaller wound. Of course, often not everything else is equal! Cutting to the inside of the branch collar (making the cut more flush) is not only making a large wound but may be cutting into the branch protection wood....which is part of compartmentalization. What greatly affects closure rates are the presence of nearby healthy branches capable of kicking some energy into the regional system. That's why, when there are no branches handy, a tree tries to make them in the form of sprouts.
Is leaving a stub ever justified? I've come to see that depending on where the living foliage is and the rest of the crown architecture, leaving a stub, especially with lateral branches of its own can be justified.

 

[ATH]

I think the wrong question is being asked in response to the knowledge of how big sounds behave. Rather than asking "does it really matter HOW I make this cut" I try to ask "Do I really need to MAKE this cut?"

If so, aesthetically, I think a proper cut looks better than a flush cut. I had a client this spring that a stub be left for a wildlife perch...

 

[Basswood]

Theoretically wouldn’t it be better to cut out further on a bigger cut where the wound may be smaller? Potentially leaving a stub.

 

[evo]

Don’t forget about excessive heart wood drying and oxygen response, or endophyidic fungi activation

 

[CjM]

I worry more about pruning high aspect ratio limbs. I've seen fairly large wounds completely calloused over on old white oaks, often far out along an old limb.

Gilman says high aspect limbs have limited collar formation, similar to true co-dominate stems, which have no branch collar or branch protection zone. He also says "there may be some protective features in unions containing heartwood because the anatomical components of the protection zone remain."

I would think cutting "inside the collar" in such a case would damage whatever viable components of the heartwood that exist, and be would be cutting into the main stem.

 

[DSMc]

Always leave as much as you can when reducing an asset. There is currently a strong bias against the aesthetics of anything that might be considered a stub, but in the case of large limb removal, it is often the better choice.