Tree World - View Single Post - Pruning cuts - collar, collarless and co-dominant

Sean Freeman · 27th February 2007, 10:15 PM

The photo you use is of a codominant union with one of the stems removed, and the red line does show the best line for the final cut, in the case of codominant stems. In pruning non codominant stems (I won't say normal because what does that mean?) the aim is to make the final cut just outside the branch collar at an angle that mirrors the branch bark ridge. I've put some diagrams in a doc attahced below

Idealised pruning angles.doc

The reason for the desire to make the final cut there is two fold, one you avoid cuting into tissue that are part of the stem, that would expose the tree to the high risk of insect/fungal pathogen colonisationof the stem...not good..two you leave the branch protection zone intact which inhances the chances of the tree quickly and effectively closing the wound very soon after the cut is made, less than an hour in some species (that is the chemical closure I'm talking about not the formation of callus tissue followed by woundwood which can take much longer)

The situatiion with codominants is more complicated because there is no branch protection zone, you are always going to be exposing stem tissues to oxygen ingress and subsequent dysfunction, the angle of the cut relates more to the attempt to reduce the epicormic growth response trying to clearly establish the remaining stem (no longer co-dominant) as the apical growing point. Its one of the hardest things to succeed with especially when the codominants have been allowed to reach the size they are in your photo. It is far better for all if they are pruned out when much smaller.

If I were the climber or bucket guy making the final cut I'll be honest my finishing cut would have been the blue line.

co-dominant1si.JPG

Mainly because it doesn't look like there is significant bark inclusion (at least on the side we can see) and I would want to reduce the surface area of wood tissue cut as much as possible, whilst reducing the likelihood of epicormic sprouts forming and perpetuating the hormonal confusion wiithin the tree as to which part is the leader.

The water thing is a bit of confusion it really isn't connected to the reasoning behind the angle of our final cut.

SF

27th February 2007, 10:15 PM	#6 (permalink)
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 1,671	The photo you use is of a codominant union with one of the stems removed, and the red line does show the best line for the final cut, in the case of codominant stems. In pruning non codominant stems (I won't say normal because what does that mean?) the aim is to make the final cut just outside the branch collar at an angle that mirrors the branch bark ridge. I've put some diagrams in a doc attahced below Idealised pruning angles.doc The reason for the desire to make the final cut there is two fold, one you avoid cuting into tissue that are part of the stem, that would expose the tree to the high risk of insect/fungal pathogen colonisationof the stem...not good..two you leave the branch protection zone intact which inhances the chances of the tree quickly and effectively closing the wound very soon after the cut is made, less than an hour in some species (that is the chemical closure I'm talking about not the formation of callus tissue followed by woundwood which can take much longer) The situatiion with codominants is more complicated because there is no branch protection zone, you are always going to be exposing stem tissues to oxygen ingress and subsequent dysfunction, the angle of the cut relates more to the attempt to reduce the epicormic growth response trying to clearly establish the remaining stem (no longer co-dominant) as the apical growing point. Its one of the hardest things to succeed with especially when the codominants have been allowed to reach the size they are in your photo. It is far better for all if they are pruned out when much smaller. If I were the climber or bucket guy making the final cut I'll be honest my finishing cut would have been the blue line. co-dominant1si.JPG Mainly because it doesn't look like there is significant bark inclusion (at least on the side we can see) and I would want to reduce the surface area of wood tissue cut as much as possible, whilst reducing the likelihood of epicormic sprouts forming and perpetuating the hormonal confusion wiithin the tree as to which part is the leader. The water thing is a bit of confusion it really isn't connected to the reasoning behind the angle of our final cut. SF