You'll have a perfect tree once again after you follow the experts advice. Allow the new shoots to grow and when is the most dominant, choose that one and stake it, straight up. This "branch" will take over and become the new leader/main trunk. When the branch you choose becomes rigid and no longer needs staking, remove the stake and you'll have a new, identical, tree. And, if any of the side shoots start to 'try' to become leaders, clip them off so your tree has the one 'new trunk'. You can also shorten the side-branches until the new leader becomes established, as needed.

Take care,

Dax

Thanks for the reply Dax. If I may ask some other questions...when you say 'stake', I assume you mean to just 'tie' the most dominant branch to a stake/support? If so, I'm just trying to understand how doing that alone would make that particular branch become the new main trunk. What exactly is it about simply tieing a branch to a support that will make it become the new leader? Or is it more the cutting off of the less dominant branches, that will allow the most dominant one to continue to become stronger and thicker?

Also, that still doesn't answer the question of the existing main trunk. How can I have a 'new, identical tree', if I will have two main trunks...a new main trunk ( growing off of the old main trunk that was cut down to 16") and the old main trunk?

Or....when you say 'stake', maybe what you really mean is that I am staking the most dominant new branch TO the existing trunk, so that it begins to grow up alongside it? If so, is this what is meant by grafting...will the dominant branch that I've chosen to stake to the existing trunk eventually MERGE somehow, or graft onto, the existing trunk? And if so, at some point do I "file down" the top of the curent trunk, which currently is just a 'stub', so that it blends more with the new trunk that is now grafted onto it?

I just can't really visualize what you are saying, or understand how I'm going to have a 'new, identical tree", when currently my main trunk is a 16" stub. I don't see how that ugly stub can ever 'disappear' simply by staking one of the newer branches onto it....

Thanks.

Anybody (before this thread gets 'buried')...??

Thanks!!

"when you say 'stake', I assume you mean to just 'tie' the most dominant branch to a stake/support?"
Yes, that is exactly what Dax was suggesting. The general idea is the you cut off the "old main trunk" at a point just above where the "new main trunk" is emerging, and that stem becomes the new leader. Eventually it will thicken and you will hardly be able to tell it was not the original trunk.

Thanks. OK, so I will stake that branch which I choose to be the new leader/main trunk, to a stake. And I understand that I then cut down the current main trunk, to just above that new leader.

Even cutting the current trunk to just above the new leader, I would imagine that even once the new leader grows stronger and thicker, that there will remain a bit of a 'stub' sticking out, from where the previous leader/main trunk was cut down? Once the tree is more established, will there be any way for me to make that 'stub' less obvious? Although I guess thinking about it some more.....most people's eyes will be focused on the nice branches/leaves....no one will be looking down at the lower portion of the trunk I suppose..

But again, that still doesn't answer my question of....how does staking alone help to make a particular branch become the 'leader' over all the other branches? Am I supposed to cut all the other little 'branches' (really they are currently more like 'suckers'...)...am I supposed to cut them all off once I've staked a new leader, in order to give it enough energy to become stronger/thicker? If not, then how exactly is staking a branch going to encourage it to become thicker per se, versus simply growing upright?

Thanks again everybody!

Staking it will force it to grow upright, and since the other branches will naturally grow to the sides, it will become the leader. It will get thicker on its own -- you don't have to cut the other branches unless one of them is competing with the leader or growing too fast or at a bad angle.

The stub will be very noticeable during the first year or so, but as the new stem grows thicker over the years the stub will eventually be encapsulated within the new trunk. There may be a slight kink in the trunk at this point, but years down the line even this will be all but invisible.

The reason that the staked branch becomes the leader is because of apical dominance. Some Japanese maples are not strongly apically dominant, you might need to help the main stem by pinching out the growing tips of any side branches.

Here is a link that might be useful: Apical dominance

Thank you so much everybody for your input. I think all my questions were answered and I now understand..it all makes sense...

So I'm very excited now to see what happens with my tree. It seems I've not got a second chance with this beauty!

I forget the exact type of Acer Palmatum it is..it's not a Dissectum, I know that much....but the leaves are normally a light green, and in the Fall they turn to orange!

:-)

IMO you have a golden opportunity here to play with shaping a JM the way most of us would never do with an undamaged tree.
I would do as suggested above, then take time every now and then to stare at it and determine what sort of shape to nudge it towards. Do some reading on pruning techniques so you know how to foster growth in a specific direction and get creative.
You could end up with a remarkably attractive specimen.