Ken, I'm not 100% sure where you're trying to get with this but it looks like a classic instance of the need for "subordination pruning". There is no branch collar/branch bark ridge present in these two co-dominant stems. Therefor, completely removing one or the other at this time will leave a bad wound-one which takes too long to close up. But if you shorten one-the less desirable one-to a side branch/branchlet, a branch collar will form. It will then be safer to completely remove it. This whole process could take a few years.

Let me know if I'm missing the purpose of your inquiry.

+oM

...and forgot to add, I would first cut off the two stubs in a normal fashion. Maybe this is the aspect I'm not getting, in terms of what you are trying to do.

+oM

Ditto to +oM. I'd keep the stem on the right, and head back the one on the left.

Resin

How far back would you cut the stem on the left?

My guess is to just above it's first two branches.

Tom, are you saying by making the head back cut it will create a collar at the main truck?

Curious as to why Ken can't just make the cut below. Given the above info perhaps its because the wound won't heal properly?

{{gwi:329481}}

Ken, is this another darn tree from Girards?

Yes whaas, sans an already-formed branch collar, the wound will close poorly. But by doing the subordination cut, that former codominant leader will begin to behave more as just another branch. In time, the BC will form and this sets the stage for complete removal later.

Someone asked where to make the sub. cut. I'd say that this is poorly understood in the industry but that in general, you can cut more off rather than less, to achieve the goal of slowing that leader down. It's not (yet) an exact science.

+oM

Let me make sure I understand the theory.

So the point is to slow the growth of the less desireable leader by cutting off a good portion of its foliage.

After that is done the un pruned portion of the trunk will grow faster and begin to encapsulate the pruned now stubby co-leader. (Or does it form a proper branch collar if left alone?)

Once the encapsulation begins you can prune off the rest. This will take two or three years?

I have seen u healthy branches or dead remaining branches begin to be encapsulated by the tree before they fall. Same theory?

Typo. Last line should read "unhealthy" branches.

Darn cell phone.

coffee buzz ... i am going to have to come back later.. to study this.. but clarify some things for me

you reject whaas red line.. yes??

second.. if you look at the right stub... there is already a wound behind it.. its a weak spot ... and i am concerned about openning that up by the stub removal .. and then making a bigger wound by removing the 2 stubs.. and the heading back the left leader ... its all so confusing ...

subordination pruning --- thx.. thats a searchable term..

hmmmm

ken

I would also reject Whaas' red line, because that would be cutting too much wood all at once. That appears to be about 50% of the wood on the overall tree, which IMO is way too much to remove for any tree let alone one that is small and newly planted. I generally don't remove more than 10-15% of wood per year on a young or recently planted/transplanted woody plant.

I was just showing the cut to get clarification as to the co-dom being cut back and "then" forming a branch collar just below or at the red line location.

I would have no worries taking the co-dom leader out now...with the exception if the wound would not close properly. That would be my only concern.

As for the 25% or less guideline I look at if from a case by case basis. Typically I follow it for trees in leaf but rarely follow it for dormant trees (ecpseically when it comes to thinning for established trees).
I just took out more than 25% canopy (mainly thinning and sucker removal) of several 50' dormant Lindens and their health improved dramatically after the new construction. AS I mentioned I always like to look at it from a case by case basis.