When chopping back to new leader, question.

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#1
I’ve read that when chopping back to new leader we should use knob cutter or grinder and carve out the trunk. I’ve also read that it should be smooth surface with absolutely no burrs or rough spots.
I am curious what gets the best results for full healing of the chop scar? Here are mine with smooth cut. Should I be using knob cutter to make it concave for better healing?
Thanks mike E9FFB90A-F876-4EDD-8E1E-73B25D18AE8A.jpeg A07F74F1-49BD-4CE7-94A3-4ACA193CEF80.jpeg 8C45BD2D-D52E-43A8-A919-A5A5D8626523.jpeg
 
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#4
It depends on the thickness of the bark. Basically, thin barked species (e.g. azalea, beech) should be flush, and thick barked species should be concave. The thicker the bark, the more concave.
How about your avg deciduous tree? Elm, hawthorn, zelkova, JM. These are the trees I’m wondering about.
Thank you, mike
 
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#5
How about your avg deciduous tree? Elm, hawthorn, zelkova, JM. These are the trees I’m wondering about.
Thank you, mike
Chinese elms have some of the thickest bark and Zelkova are slightly less thick. Japanese maples are rather thin barked and should be slightly concave. I don't have any experience with hawthorn.
 
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#7
I thought you were supposed to chop that close to the branch collar???
I guess that is depending on the species perhaps???
 
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#8
I thought you were supposed to chop that close to the branch collar???
I guess that is depending on the species perhaps???
Did you mean weren’t or we’re supposed to chop that close to the new leader?
Well this is why I’ve made this post because I see a lot of conflicting info on how to handle a chop.
 

Bonsai Nut

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#9
Does anyone have pictures of their chop scar healing? Preferably the chop and healed over results after?
I do not have a 100% healed chop scar. But I do have one that is about 50% and is clearly headed in the right direction. I'll post photos tomorrow.
 
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#11
This one is almost healed over. I’ll try to update the thread this weekend.
Thanks Brian seems like both smooth and concave are the way to go?
I do not have a 100% healed chop scar. But I do have one that is about 50% and is clearly headed in the right direction. I'll post photos tomorrow.
Thank you!
 

Bonsai Nut

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#12
Here is a chopped Catlin elm for reference:

I had an ugly s-shaped pre-bonsai that I had had for years and was not happy with in the slightest. It was buried away in my "neglect" area :)

elm1.jpg

So I did this to it, removing the lowest branch (digging out a deep concavity) and turning the stub of the 2nd branch into the new leader.

elm2.jpg

And here it is today. Still working on the roots, as you can see from the new scar at the soil line where I removed a big ugly root this spring.

elm3.jpg

Front scar is healed almost completely. Top scar (from the trunk chop) looks like this. Nice girdle of closing bark - every year getting a little smaller:

elm4.jpg
 
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#13
Here is a chopped Catlin elm for reference:

I had an ugly s-shaped pre-bonsai that I had had for years and was not happy with in the slightest. It was buried away in my "neglect" area :)

View attachment 200857

So I did this to it, removing the lowest branch (digging out a deep concavity) and turning the stub of the 2nd branch into the new leader.

View attachment 200858

And here it is today. Still working on the roots, as you can see from the new scar at the soil line where I removed a big ugly root this spring.

View attachment 200859

Front scar is healed almost completely. Top scar (from the trunk chop) looks like this. Nice girdle of closing bark - every year getting a little smaller:

View attachment 200860
Did you concave the big chop? Looks like you did not but I can tell. How many years ago did you do the chop? Also I like tree and the way it’s progressing much better then the S shape. Thank you
 

Bonsai Nut

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#14
I'd have to go home to see how long it has been since I trunk chopped it. When planning how far you want to cut below the surface Into the Heart Wood you have to plan for the thickness of the bark that will eventually cover the wound. if you want a completely flush scar you have to cut a concave wound. But if you want a bulge or a different shape that will work better with your future plans for the tree you can leave more Heartwood.
 

0soyoung

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#15
I'd have to go home to see how long it has been since I trunk chopped it. When planning how far you want to cut below the surface Into the Heart Wood you have to plan for the thickness of the bark that will eventually cover the wound. if you want a completely flush scar you have to cut a concave wound. But if you want a bulge or a different shape that will work better with your future plans for the tree you can leave more Heartwood.
Spherically concave as made with a knob cutter or concave as a cut made with a concave cutter AND IF a cut made with a concave cutter, is the valley horizontal or vertical (of course, it may be that the cut is flat and the profile is formed by power tools)?

btw, I think you mean live wood or simply wood as the Heart Wood is the dead wood at the core of a bole which has a darker color, often a distinctive reddish hue.
 

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