Trunk chopping Japanese Maple

[Krisb1]

When trunk chopping do you need branches below the trunk chop or will it back bud automatically. I’m not doing it yet I have two air layers going right now in the canopy of the tree but I wanted to prepare myself for the up and coming autumn season.

 

[Shibui]

JM will usually grow new buds from bare wood after a chop.
Occasionally I've had one fail to sprout but not often.
Looks like that one is grafted. Some propagators excise any buds from the rootstsock at grafting so the tree can't sucker. Those trees may not sprout if you cut down below the graft but i guess you intend to chop above the grafted area.

BTW, really hard to see much in those photos with back lighting.

 

[Krisb1]

No not grafted... all that is were a family of rabbits gnawing away at the tree so I had to dig it up early

 

[Krisb1]

There is absolutely no tap root... there den was directly under the tree.. they ate everything

 

[Shibui]

No not grafted... all that is were a family of rabbits gnawing away at the tree so I had to dig it up early

The change of bark colour looks like a graft union. Even looks like a diagonal line - so much like a graft site.
As it is not grafted the trunk should produce new buds after a chop. Just be aware that parts of larger JM trunk sometimes die off after chops. the tree usually survives but maybe not all of the trunk.
I find that very few trees actually have this mythical tap root. Even without rabbits trees rely mostly on shallow laterals so very few of the trees I have dug have really strong vertical roots.

 

[Krisb1]

These are better photos in the light...

 

[Captain.Bonsai]

The change of bark colour looks like a graft union. Even looks like a diagonal line - so much like a graft site.
As it is not grafted the trunk should produce new buds after a chop. Just be aware that parts of larger JM trunk sometimes die off after chops. the tree usually survives but maybe not all of the trunk.
I find that very few trees actually have this mythical tap root. Even without rabbits trees rely mostly on shallow laterals so very few of the trees I have dug have really strong vertical roots.

I’d add the sudden/unnatural change of trunk angle at the diagonal ‘not-a-graft’ line you your list of evidence.

 

[Shibui]

I’d add the sudden/unnatural change of trunk angle at the diagonal ‘not-a-graft’ line you your list of evidence.

All the evidence is circumstantial and the owner has given a categorical no. There are many possible causes that could impersonate a graft.

The rabbits have certainly been having fun with this one above ground as well as below.

I remember asking one client whether she had a rabbit problem because all the fruit trees I was pruning had bark damage low down on the trunk. She was pretty sure they did not have rabbits. Later I realised all the damage was a similar height and pattern and worked out that the culprit was more likely a line trimmer and reported my new theory to the owner.
Glad I was not there when hubby came home.....

 

[parhamr]

Is it growing indoors?! I’m skeptical you can get it enough light and airflow to make those air layers successful. It takes a lot of light—75,000 to 100,000 lux—to replace the sun.

Additionally, if there are no branches below the air layers then it’s likely you will starve the roots, which is fine for layering, but will make it really difficult to have a successful trunk chop.

 

[Krisb1]

I was afraid the air layers would freeze so against my better judgement I brought it inside. It is budding out and I have lots of leaves above the air layers, I have panoramic windows in my office which is now just the home of this 8 ft tree but the windows face SE so it get the morning sun... it has a drip system, Dehumidifier, and fan for air circulation...

 

[leatherback]

Comes to mind.. WHen did you put the airlayers on? A regular palmatum should have roots in 4-6 weeks in the right time of year.

Not trying to be mean, but.. In fact, you have lost a year compared to doing this in the right season.

 

[Krisb1]

Yeah that’s the curse of being new to bonsai... making a lot of mistakes, but luckily I found this forum... to absorb as much of the knowledge that all of you have... and not to mention I had a weevil problem in the air layers as well... learned that the hard way...

 

[parhamr]

Yeah that’s the curse of being new to bonsai... making a lot of mistakes, but luckily I found this forum... to absorb as much of the knowledge that all of you have... and not to mention I had a weevil problem in the air layers as well... learned that the hard way...

I’m glad you’re receptive to this discussion and feedback! I’m not trying to rag on you.

That window light is about 10x too little to be successful. Acer palmatum are known as “mountain maples” and so that might give you a hint of their tolerance for cold. I recommend it goes back outside so the air layers can produce the most energy (and roots) possible.

 

[Krisb1]

Will give it a shot... fingers crossed...