Novice: Chinease Elm. Advice and thoughts?

[Mr.Dr.K]

This is my 1st and only Bonsai which was gifted to me about 2.5 years ago. At first I didn't know much about the species of tree, pruning etc... but managed to keep the tree alive and healthy. I don't have pics from when I 1st got it, but it has grow significantly.
After reading a little on Bonsai, I have an idea on what I'd like to do and correct, but would like some advice and constructive- criticism. As you likely see, there is no real style to the tree; I have been playing with it and seeing how it reacts and learning how to care for it. I have finally purchased my 1st set of Branch Cutters.
I've decided I'd like to allow it to grow to develop a larger trunk and eventually do a broom-style, which will involve a trunk-chop in the future. There is some reverse-taper near the top, which will eventually get chopped below that point. I would like to develop the trunk more down low rather than up top to correct the issue of reverse taper while it is young. Currently it is In a small pot—last reported the end of summer around September; I planed on slip-potting into a larger pot the end of winter. My question is: to develop the base of the trunk vigorously and avoid reverse taper, should I start some sacrificial branches down low, or air layer the base of the trunk to promote Nebari and maybe prune the apex vigorously to avoid the trunk thickening up-top and allow more light down low?
Currently, it is the beginning of January; the tree just lost all of its leaves and has begun to show leaf buds at the tips of the young branches. The 1st year I got the tree, it was an indoor tree and then I moved it outdoors permanently. It rarely freezes where I live in Southern Oregon on the Valley Floors, although, last week it was subjected to several days of freezing nightly temperatures but warmed during the day.
Anyway, I'd love some feedback, thoughts and ideas. Any recommendations on when to do major work and technique is also welcome. Thanks in advance. Cheers.

 

[Shibui]

Having good radial roots will help the base of the trunk flare out and thicken down low so rather than slip pot in spring I would advise to bare root and prune roots to promote good nebari. If you find poor rootage layer would be advised. Chinese elm can take quite severe root pruning if necessary.
Broom style tends to have minimal taper so don't worry too much about how the trunk thickens. Provided you chop the thickened section off it should be OK.
Broom style should ideally have a straight and vertical trunk. The current trunk seems to have a slight bend but that should disappear if it thickens enough.
For maximum trunk thickening I'd leave all the current branches in place and only remove them if any get out of hand or when the trunk has thickened. I don't think any current branching will cause undue problems as it grows.

I do most work on Chinese elm in late winter/spring as they begin to grow. Mine often start to bud just after mid winter and it sound like your climate is similar.

 

[Mr.Dr.K]

Having good radial roots will help the base of the trunk flare out and thicken down low so rather than slip pot in spring I would advise to bare root and prune roots to promote good nebari. If you find poor rootage layer would be advised. Chinese elm can take quite severe root pruning if necessary.
Broom style tends to have minimal taper so don't worry too much about how the trunk thickens. Provided you chop the thickened section off it should be OK.
Broom style should ideally have a straight and vertical trunk. The current trunk seems to have a slight bend but that should disappear if it thickens enough.
For maximum trunk thickening I'd leave all the current branches in place and only remove them if any get out of hand or when the trunk has thickened. I don't think any current branching will cause undue problems as it grows.

I do most work on Chinese elm in late winter/spring as they begin to grow. Mine often start to bud just after mid winter and it sound like your climate is similar.

Thank you for taking the time to reply. I cut the wire that was holding the tree in the pot and elevated the tree and pot by the trunk-base. It appears to have rooted well since repotting last. I will follow your advice and bare root the tree and trim the roots and allow it to grow this season and see how it does. Thank you.