Reduction Pruning Help

HigherGroundArborist

Active Member
Location
Granger
So, unless I missed it, I didn’t see a section on TreeBuzz dedicated to discussions on pruning. So, here’s my question in the general discussion. our company manages the trees on 4 Apartment complexes in our area. Today I was inspecting a tree that I pruned in February 2019, almost 2 years ago. It is a Red Maple (Acer Rubrum) and has some serious structural deficiencies at the base. The client who owns the apartment complexes does not want trees removed if not absolutely necessary. So, I reduced quite a bit of weight on the outer canopy 2 years ago and feel that the tree is safe with regular monitoring. When I was inspecting the canopy today, I was surprised to find that many of my reduction cuts were not being compartmentalized the way that I thought that they should. The top part of my cut appears like I would expect with wound wood forming, however, below my cuts the wound wood was developing way down the branch, far from my cut. I’ve included some pictures of one cut in particular.

How can I make a better cut here? If I cut way down to where the bottom wound wood is forming it opens up a much larger area and is a strange cut to me. I’ve drawn a red line on one of the pictures to show how this cut would go. I love pruning trees, and I’m hoping some of you can provide some feedback so that I can improve my pruning technique. Thanks.
 

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oldoakman

Well-Known Member
Location
Alorgia
They appear to be codominant leaders. You are correct, the woundwood begins to form back down the stem where you show the red line. Shigo suggests imagining a line perpendicular to the end of the bark ridge and cut from there up to just the edge of the top of the bark ridge. This is what the tree is doing anyway. Red Maples are notorious for codoms.
 

HigherGroundArborist

Active Member
Location
Granger
They appear to be codominant leaders. You are correct, the woundwood begins to form back down the stem where you show the red line. Shigo suggests imagining a line perpendicular to the end of the bark ridge and cut from there up to just the edge of the top of the bark ridge. This is what the tree is doing anyway. Red Maples are notorious for codoms.
Thanks for the reply @oldoakman. So, if I’m understanding you correctly, the steep angled cut indicated by my red line in the picture would be a more appropriate cut. I also dug up this slide from the California Rare Fruit Growers website (https://crfg.org/) that suggests exactly what you’re talking about. Draw an imaginary line perpendicular to the branch and split the difference between that line and the branch bark ridge. Thanks for your help!
 

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oldoakman

Well-Known Member
Location
Alorgia
Thanks for the reply @oldoakman. So, if I’m understanding you correctly, the steep angled cut indicated by my red line in the picture would be a more appropriate cut. I also dug up this slide from the California Rare Fruit Growers website (https://crfg.org/) that suggests exactly what you’re talking about. Draw an imaginary line perpendicular to the branch and split the difference between that line and the branch bark ridge. Thanks for your help!
You got it. I'm on vacation now but when I get back I'll post Shigo's diagram.
 

TreeVB

Well-Known Member
Location
Boise, Idaho
Hard to tell from photos but look like decent sized cuts. I personally would have cut a bit further out leaving a stub to potentially encourage some epi to develop on. Since this tree will be closely monitored you will easily be able to monitor/maintain the sprouts. Also difficult to know the state of the tree without photo of said deficiencies. Are we talking an inclusion, vascular distress, large wound? Another thing to consider is smaller cuts further out.
 
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HigherGroundArborist

Active Member
Location
Granger
Hard to tell from photos but look like decent sized cuts. I personally would have cut a bit further out leaving a stub to potentially encourage some epi to develop on. Since this tree will be closely monitored you will easily be able to monitor/maintain the sprouts. Also difficult to know the state of the tree without photo of said deficiencies. Are we talking an inclusion, vascular distress, large wound? Another thing to consider is smaller cuts further out.
The cut above is 2” in diameter. I’m mostly looking for feedback on making proper reduction cuts so that the tree can close them as efficiently as possible. I’m not sure I want this thread to morph into a critique of my pruning and care for this particular tree. That makes me nervous
 

TreeVB

Well-Known Member
Location
Boise, Idaho
The cut above is 2” in diameter. I’m mostly looking for feedback on making proper reduction cuts so that the tree can close them as efficiently as possible. I’m not sure I want this thread to morph into a critique of my pruning and care for this particular tree. That makes me nervous
Wasn’t trying to critique your pruning so sorry it came off that way. You did ask “how can I make a better pruning cut here” which made me think you were looking for ideas. I’m sure you will get lots of great info on this particular tree.
 

ATH

Well-Known Member
Location
Ohio
A few thoughts:

1) Summer pruning wounds certainly close quicker. However, who has time to prune every tree during the growing season? Also, if the client calls in September, they probably aren't thinking they should wait 8-9 months to get their tree pruned. A counter argument is that disease transmission is less significant during dormant pruning.
2) Sap flow is not a problem.
3) Yes, on bisecting that perpendicular line and the ridge. I do agree, that "feels" a little odd or aggressive when making that cut. I can pretend come up with other ideas, but I'd have look harder at Shigo's research and do my own before suggesting there is a better way. I'm not saying there cannot be a better way...just that we have pretty good documentation from Shigo cutting and photographing a LOT of trees a lot of different ways and the results are readily available.
4) If possible, perhaps make a reduction cut further out on that branch taking away most of the mass/load on that branch with the idea of coming back in the future to make that cut. This won't make that cut smaller, but smaller in proportion to the piece you are leaving which will help with wound closure.
 

guymayor

Well-Known Member
Location
East US, Earth
First, those cuts look like removal cuts. A reduction cut would be further out. Since there is no collar on codoms, what is the advantage of cutting that far back? ATH and VB are right on this.
P.S. Ignore the 1/3 rule.

Second, different general have different architecture. Removal cuts on maples should be more slanted than on oaks, for instance. Below pics of maples from research at Biomechanics Week. A lot of 2" cuts on silver maples had poor results, so another study started up with 1" cuts.

1607966228489.png
 

TreeVB

Well-Known Member
Location
Boise, Idaho
Curious as to thoughts on this, especially on an immature tree taking one of the leaders would stop the included-bark acute angle and help mitigate future-failure, correct? Not making an argument for way up in the crown, more of the early on pruning.
Valid question. IMO it would depend on how bad the inclusion is. If it is really bad, tree is immature, and species allows, removal could be best choice. However, the inclusion is concern for failure so mitigating it through reduction would mitigate the fear of failure and relieve competition by redirecting apical dominance. Always keep in mind that this profession is a tree by tree basis so the “prescription” will always vary. That’s my take on it and how I tend to address these “issues”.
 

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