Larch root fusion

I recently purchased this American Larch from Bill Valavanis. It was originally a yamadori. It has this root extending higher up with a gap between it and the main trunk. I placed a paper behind it to better view the opening. Any suggestions of how this gap can be closed? Can i scar the inside of the gap and place moss or soil in hopes of root growth in the gap which will eventually close? Any suggestions would be appreciated.

If you want to close that gap you’ll need to get this tree pumping hard. Lay off of foliage pruning and just let it go wild.
It’s pretty slow going to try and thicken a trunk while working on the foliage mass. I think raising the soil line a little will help improve the look of the tree in the short term.