Pruning cuts - collar, collarless and co-dominant

Ekka · 26th January 2007, 02:38 PM

At the roadside again having a look at some pruned trees. This is the same place where the two stumps were so most likely the same contractors.

I took some pics of their finishing cuts.

This was a great opportunity for the 3 standard cuts that pretty much dominate our industry. When all is said and done these 3 cuts are about all you need to know.

There are 3 types of branch unions.

Collar
Collar-less
Co-dominant

And that's it! Hence only 3 cuts, so how easy is life really when pruning? Sure some people will complicate it and say there's a cent-time cut where you leave 3mm of stub to compensate for rot, there's others that say there's a heading cut on a slight angle just above a node etc like you'd do with a pair of secateurs to roses. But in trees work this is pretty much it .... and in this example you'll see what they did.

However do remember that you should try to keep the cuts small, so do this before branches get big. Rule of thumb they reckon is 4" dia or 100mm dia in the metric scale.

Remember, we are talking about finishing cuts, some argue that you can leave a stub for a year ... return then whack it again, prepares the collar for more defences, but eventually after many reductions and returns you are going to end up making a finishing cut.

In the next bunch of pic's you'll see the red line where they should have cut it.

In the second to last pic have a look at the epicormics that have decided to grow due to the poor cut made.

Link to stumps at same location.
Road side stump cut analysis - Tree World

Collarless union

Collar

Extended Collar

Codominant

jim1nz · 31st January 2007, 12:29 PM

If this deadwood was removed, the trees callus wood would have already occluded the wound.

mdvaden · 27th February 2007, 07:43 PM

I've seen some oldery English Holly, crabapple and grand fir, where the branch collar of the lower limbs was from 2" to 6" out from the trunk, although that's not the norm.

l2edneck · 27th February 2007, 08:05 PM

that is a nasty cut in my book.I was always taught to do a 45 so water can run off and not give any chance to sit and rot.I imagine the redline is demonstrating proper cut?

Notahacker · 27th February 2007, 09:42 PM

It looks like those guys are all over the place when it comes to making a good collar cut. Inconsistent cuts? What's wrong with those guys?

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

Ekka · 28th February 2007, 12:52 AM

Here's the collar cut, they're in the pics in the first post.

Boa, surface area is a falacy, if Shigo were alive today he'd tell you the same. At a seminar Brett Hamlin asked Shigo if it would be better to take a shallower angle reducing the surface area ... Old Shigo gazed sternly and said that's not the case and suggested he read more of his books. lol

The bottom of the BBR is the guide.

Ekka · 28th February 2007, 12:54 AM

Here's the collar cut, they're int he pics in the first post.

Boa, surface area is a falacy, if Shigo were alive today he'd tell you the same. At a seminar Brett Hamlin asked Shigo if it would be better to take a shallower angle reducing the surface area ... Old Shigo gazed sternly and said that's not the case and suggested he read more of his books. lol

The bottom of the BBR is the guide.

Check AS4373, also the same.

Sean Freeman · 28th February 2007, 01:11 AM

Well as I said its where I would have made the cut in the photo, Shigo certainly has it over me and I have read all his published works even the USFD papers, I'm not disputing that his knowledge and understanding is superior to mine it was and is. Just that in the case of co-dominant stems there is no branch protection zone, all you are trying to achieve is to encourage the effective closure of the wound, and limit the production of epicormics..look if the co-dominant is advanced enough with enough live foliage and demanding equal if not greater rights to Auxin and Gibberelin control it you'll get epicormics. My concern when removing co-dominants like the one in the photo is to balance two objectives, effective closure limiting the amount of dysfunction my cut produces and reducing epicormic growth as much as poss.

Shigo's instructions re co-dominants to hit the bottom mark extended from the bottom of the BBR across to the outer bark I understand perfectly, and don't dispute. His main point was to warn of the dangers of leaving a stub live (for a time) but without a defense system. I don't consider the difference between the red line and the blue line in the photo to be that great...red line less wood tissue left agreed, but more wood tissue surface area exposed to dysfunction, the impact of which on urban trees already experiencing multiple streeses should not be ignored. The blue line attempts to split hairs by lifting the bottom slightly to reduce that area.

It's just my opinion Ekka, its not me saying Shigo's wrong and I'm right, Shigo is right I just want to try to protect the tree more, if my tree biology is wrong here I'll take pointers please.

SF

l2edneck · 28th February 2007, 08:30 PM

Quote:

trying to achieve is to encourage the effective closure of the wound, and limit the production of epicormics..look if the co-dominant is advanced enough with enough live foliage and demanding equal if not greater rights to Auxin and Gibberelin control it you'll get epicormics.

Quote:

I don't consider the difference between the red line and the blue line in the photo to be that great...red line less wood tissue left agreed, but more wood tissue surface area exposed to dysfunction

My concern with cuttin on the blue line instaed of the red line.would be simply to cut along the red line so the finish is below the lilttle latteral that would be left just below the blue line cut.

If left unnatended would keep the wound open and also fight for dominance.At the same time getting heavy and being on the side of the stem leaving more room for failure due to what i have dubbed the "peel effect".

This IMO could be avoided with the redline cut as long as no sprouts or suckers as we call them are left on the other side above the finish cut....
(Now that would be a cleanup cut (both red and blue) ,obviously its not healing because it was cut wrong to begin with..Easy collar cut could have been made at the initial trim.)

Personally i think that if it grows that good and comes back im questioninq why leave the other side.But i have no clue about gums in Au.

Ekka · 28th February 2007, 10:57 PM

I also laid the challenge down somewhere about the myth of heartwood not having defense capabilities ... so did Shigo.

It's common thought to say co-dominants have no branch protection zone, hey, there's just heartwood and that's the only defense so leaving more of it should do better????

I accept the rationale and logic of this. I also used to prune way shyer of the red line till say the last 7 years.

There's defense capabilities of heartwood, we need to find some facts on this but I can only find generalized statements and some diagrams showing whats called the barrier zone where the heartwood alters.... but no real scientific data.

Also, perhaps cutting to the red line will mean faster closure. On some species I noticed that cutting off the mark resulted in the bark dying back a bit and bit of a dead stub. Remember back in the old days they flush cut as closure was rapid. In Shigo's dissected trees you could clearly see how the living part formed a barrier and the wound was compartmentalized.

I'm a red line cutter too

Sean Freeman · 1st March 2007, 01:22 AM

Well i seem to have merely produced more confusion rather than some clarification which was my intention, and thats definately down to me not being able to explain what I mean i quess. So I'll try to be clearer, and please note I'm not suggesting that others have said this merely that I hoope this makes my opinion on cutting co-dominants clearer...

So what I don't mean:
Pruning cuts on codominants should be perpendicular or (close to it) to the outside of the branch or limb, no.
Pruning cuts should be flush, no never.
That heartwood is dead, no its not, (but its not alive either)
That heartwood has no defensive processes or mechanisms, no heartwood does have those processes and mechanisms otherwise CODIT as a model would not be applicable.

So what I do mean: There are no collars at the union between two co-dominant stems (If it helps this is a quote from Shigo Tree Pruning Worldwide Guide pg 156) making the correct cut as described by Shigo for many of the trees I cut is very hard to pick, there are no give aways as to the bottom of the stem bark ridge.
The resulting estimate I have feared that I am getting too close to being flush, cutting into more timber than I should, so I have lifted the bottom of the cut. It is splitting hairs and reflects doubts I have about my own abilities, and if I came across as lecturing on what others should or should not make their practice that wasn't my intention.
If you as the person cutting are comfortable in the species you work on in making the cut at the "red line" all well and good. In some of the species I work on it's an easy pick too, in others it is by no means easy so I err on the side of the "blue line"

It is always preferrable to have co-dominant stems removed when they are small, when the tree is young. By the time the tree gets to the size in the original photo by Ekka the impact on the tree system of removing that codominant(if it were a healthy energy producing limb) will be to stimulate massive changes in hormonal control of epicormic buds, not just in the immediate area of the cut near the union but more often than not along the remaining limb itself. (Now that will often happen no matter where you cut, but I don't mean it doesn't matter where you make the final cut, I don't mean just lop it off cause she's going to sprout.) The epicormics that are produced are not always a bad thing for the tree, but if they are around the lip of the cut of course they will have to be removed. In some of the older trees I work on epicormics are a signal of increasing stresses sure but they are very important to the maintenance of energy levels within the tree as a whole, so I'll leave all those with no target, that I can see have half a chance of forming reasonable branch architecture in 5-10 yrs.
There is no branch protection zone behind the cut you make in the case of codominant stems there is a barrier zone that forms in the wood grown after the cut is made, but "co-dominant stems do not have protection barriers" (again if it helps that is Shigo Modern Arboriculture pg 108) So again my cutting slightly above the "red line"is about trying to ensure that I don't end up making an error that results in excessive cambial dieback under the cut opening up the limb to increased borer attack (longicorns in the case of the Albizia saman I spend so much time looking after)

Look I hope that's clearer about where I'm coming from?

SF

Ekka · 1st March 2007, 01:53 AM

Yeah, that's real clear.

Just kidding.

Boa, we gotta get some pics now of different cuts that were done a while ago and have a look.

I draw your attention to Exhibit A, this was a co-dominant cut more so toward the blue line than the red. Now the reason why the bark has gone to where you can see callus wood growing is because I broke it off by hand to see if closure was taking place. Note where it was cut it died. So if this cut were more on the mark of a red line it would have been hunky dory. Also as you cannot see the bottom of the BBR but just note where the callus growth has occured ... way lower than you'd expect, more toward that flusher zone.

Now because the guy who cut this stayed away from the red line the wound will be exposed longer as the callus has to grow more distance to cover the dead stub which is a bug feast.

Sean Freeman · 1st March 2007, 02:11 AM

Ekka, couple of points; 1) the cut you show is almost perpendicular to the branch, thats not the cut I would have made.
2) The tree species I'm not sure? Would seem to be a relatively weak compartmentaliser, so perhaps I would have moved closer to the red line than the blue, but hey mate the difference between the two would be flat out being 20mm. If It is a relatively weak compartmentaliser (maybe not as bad as Delonix) then I don't think even if you hit the cut on the red line mark you'd prevent that cambium dieback, so you'd still have the insect feast countered by the vitality and energy reserves of the tree.
If I can see the stem bark ridge then yes I would make my best attempt to cut strictly according to Shigo's model, if I can't and maybe its my eyes but on many trees i work on i can't see it, then my cut will move fractionally up to the blue line. But its in no way a stub that I leave.

SF

27th February 2007, 07:43 PM	#3 (permalink)
mdvaden Over mature heritage tree Join Date: Feb 2007 Location: Oregon Posts: 531	I've seen some oldery English Holly, crabapple and grand fir, where the branch collar of the lower limbs was from 2" to 6" out from the trunk, although that's not the norm. __________________ ____________________________________ Grove of Redwood TITANS Oregon BIGOOT trap

27th February 2007, 09:42 PM	#5 (permalink)
Notahacker Sappling Join Date: Feb 2007 Location: Longmont, CO Posts: 17	It looks like those guys are all over the place when it comes to making a good collar cut. Inconsistent cuts? What's wrong with those guys? __________________ "Quality costs as much as it saves." My great uncle Simon Murphy

28th February 2007, 12:52 AM	#7 (permalink)
Ekka Admin - Dip Arb & Hort Join Date: Jan 2007 Location: Brisbane Posts: 7,748	Here's the collar cut, they're in the pics in the first post. Boa, surface area is a falacy, if Shigo were alive today he'd tell you the same. At a seminar Brett Hamlin asked Shigo if it would be better to take a shallower angle reducing the surface area ... Old Shigo gazed sternly and said that's not the case and suggested he read more of his books. lol The bottom of the BBR is the guide. __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

28th February 2007, 12:54 AM	#8 (permalink)
Ekka Admin - Dip Arb & Hort Join Date: Jan 2007 Location: Brisbane Posts: 7,748	Here's the collar cut, they're int he pics in the first post. Boa, surface area is a falacy, if Shigo were alive today he'd tell you the same. At a seminar Brett Hamlin asked Shigo if it would be better to take a shallower angle reducing the surface area ... Old Shigo gazed sternly and said that's not the case and suggested he read more of his books. lol The bottom of the BBR is the guide. Check AS4373, also the same. __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

28th February 2007, 10:57 PM	#11 (permalink)
Ekka Admin - Dip Arb & Hort Join Date: Jan 2007 Location: Brisbane Posts: 7,748	I also laid the challenge down somewhere about the myth of heartwood not having defense capabilities ... so did Shigo. It's common thought to say co-dominants have no branch protection zone, hey, there's just heartwood and that's the only defense so leaving more of it should do better???? I accept the rationale and logic of this. I also used to prune way shyer of the red line till say the last 7 years. There's defense capabilities of heartwood, we need to find some facts on this but I can only find generalized statements and some diagrams showing whats called the barrier zone where the heartwood alters.... but no real scientific data. Also, perhaps cutting to the red line will mean faster closure. On some species I noticed that cutting off the mark resulted in the bark dying back a bit and bit of a dead stub. Remember back in the old days they flush cut as closure was rapid. In Shigo's dissected trees you could clearly see how the living part formed a barrier and the wound was compartmentalized. I'm a red line cutter too __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

27th February 2007, 08:05 PM	#4 (permalink)
l2edneck Palm Tree Rat Join Date: Feb 2007 Location: Florida Posts: 49	that is a nasty cut in my book.I was always taught to do a 45 so water can run off and not give any chance to sit and rot.I imagine the redline is demonstrating proper cut?

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: 1,735	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

28th February 2007, 01:11 AM	#9 (permalink)
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 1,735	Well as I said its where I would have made the cut in the photo, Shigo certainly has it over me and I have read all his published works even the USFD papers, I'm not disputing that his knowledge and understanding is superior to mine it was and is. Just that in the case of co-dominant stems there is no branch protection zone, all you are trying to achieve is to encourage the effective closure of the wound, and limit the production of epicormics..look if the co-dominant is advanced enough with enough live foliage and demanding equal if not greater rights to Auxin and Gibberelin control it you'll get epicormics. My concern when removing co-dominants like the one in the photo is to balance two objectives, effective closure limiting the amount of dysfunction my cut produces and reducing epicormic growth as much as poss. Shigo's instructions re co-dominants to hit the bottom mark extended from the bottom of the BBR across to the outer bark I understand perfectly, and don't dispute. His main point was to warn of the dangers of leaving a stub live (for a time) but without a defense system. I don't consider the difference between the red line and the blue line in the photo to be that great...red line less wood tissue left agreed, but more wood tissue surface area exposed to dysfunction, the impact of which on urban trees already experiencing multiple streeses should not be ignored. The blue line attempts to split hairs by lifting the bottom slightly to reduce that area. It's just my opinion Ekka, its not me saying Shigo's wrong and I'm right, Shigo is right I just want to try to protect the tree more, if my tree biology is wrong here I'll take pointers please. SF

1st March 2007, 01:22 AM	#12 (permalink)
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 1,735	Well i seem to have merely produced more confusion rather than some clarification which was my intention, and thats definately down to me not being able to explain what I mean i quess. So I'll try to be clearer, and please note I'm not suggesting that others have said this merely that I hoope this makes my opinion on cutting co-dominants clearer... So what I don't mean: Pruning cuts on codominants should be perpendicular or (close to it) to the outside of the branch or limb, no. Pruning cuts should be flush, no never. That heartwood is dead, no its not, (but its not alive either) That heartwood has no defensive processes or mechanisms, no heartwood does have those processes and mechanisms otherwise CODIT as a model would not be applicable. So what I do mean: There are no collars at the union between two co-dominant stems (If it helps this is a quote from Shigo Tree Pruning Worldwide Guide pg 156) making the correct cut as described by Shigo for many of the trees I cut is very hard to pick, there are no give aways as to the bottom of the stem bark ridge. The resulting estimate I have feared that I am getting too close to being flush, cutting into more timber than I should, so I have lifted the bottom of the cut. It is splitting hairs and reflects doubts I have about my own abilities, and if I came across as lecturing on what others should or should not make their practice that wasn't my intention. If you as the person cutting are comfortable in the species you work on in making the cut at the "red line" all well and good. In some of the species I work on it's an easy pick too, in others it is by no means easy so I err on the side of the "blue line" It is always preferrable to have co-dominant stems removed when they are small, when the tree is young. By the time the tree gets to the size in the original photo by Ekka the impact on the tree system of removing that codominant(if it were a healthy energy producing limb) will be to stimulate massive changes in hormonal control of epicormic buds, not just in the immediate area of the cut near the union but more often than not along the remaining limb itself. (Now that will often happen no matter where you cut, but I don't mean it doesn't matter where you make the final cut, I don't mean just lop it off cause she's going to sprout.) The epicormics that are produced are not always a bad thing for the tree, but if they are around the lip of the cut of course they will have to be removed. In some of the older trees I work on epicormics are a signal of increasing stresses sure but they are very important to the maintenance of energy levels within the tree as a whole, so I'll leave all those with no target, that I can see have half a chance of forming reasonable branch architecture in 5-10 yrs. There is no branch protection zone behind the cut you make in the case of codominant stems there is a barrier zone that forms in the wood grown after the cut is made, but "co-dominant stems do not have protection barriers" (again if it helps that is Shigo Modern Arboriculture pg 108) So again my cutting slightly above the "red line"is about trying to ensure that I don't end up making an error that results in excessive cambial dieback under the cut opening up the limb to increased borer attack (longicorns in the case of the Albizia saman I spend so much time looking after) Look I hope that's clearer about where I'm coming from? SF

1st March 2007, 01:53 AM	#13 (permalink)
Ekka Admin - Dip Arb & Hort Join Date: Jan 2007 Location: Brisbane Posts: 7,748	Yeah, that's real clear. Just kidding. Boa, we gotta get some pics now of different cuts that were done a while ago and have a look. I draw your attention to Exhibit A, this was a co-dominant cut more so toward the blue line than the red. Now the reason why the bark has gone to where you can see callus wood growing is because I broke it off by hand to see if closure was taking place. Note where it was cut it died. So if this cut were more on the mark of a red line it would have been hunky dory. Also as you cannot see the bottom of the BBR but just note where the callus growth has occured ... way lower than you'd expect, more toward that flusher zone. Now because the guy who cut this stayed away from the red line the wound will be exposed longer as the callus has to grow more distance to cover the dead stub which is a bug feast. __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

1st March 2007, 02:11 AM	#14 (permalink)
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 1,735	Ekka, couple of points; 1) the cut you show is almost perpendicular to the branch, thats not the cut I would have made. 2) The tree species I'm not sure? Would seem to be a relatively weak compartmentaliser, so perhaps I would have moved closer to the red line than the blue, but hey mate the difference between the two would be flat out being 20mm. If It is a relatively weak compartmentaliser (maybe not as bad as Delonix) then I don't think even if you hit the cut on the red line mark you'd prevent that cambium dieback, so you'd still have the insect feast countered by the vitality and energy reserves of the tree. If I can see the stem bark ridge then yes I would make my best attempt to cut strictly according to Shigo's model, if I can't and maybe its my eyes but on many trees i work on i can't see it, then my cut will move fractionally up to the blue line. But its in no way a stub that I leave. SF