..... perhaps I can use half or 3/4 of that taproot as a trunk so the chopped section would become the first set of upper branches. Not following you, but what about reverse taper?

Al

Good point about the taper. I was just assuming that the new root base which would spread lateraly would handle that, since the upper root doesn't appear to taper at all and is the same thickness as what would have been a trunk.

I just meant the tap root would go about 5" above the new soil level and where the elm is shooting out branches from its former base would be the start of the canopy.

I'm going to have to upload a photo soon!

I would just do a tourniquet. it will eliminate the tap root and at the same time create a nice wide base.

I'm fairly new to this bonsai thing, but my understanding is there are often two opposing approaches regarding the roots to widen the bottom of the truck. The first is the tourniquet option, and the second is that there often IS a lot of healthy tree-trunk below the dirt! Now, I've never grown elm, but whenever I re-pot, I brush the dirt off all the roots, including at the base of the trunk. I feel like I get approximately 1-2% the height of the plant added to the base of the trunk (depending on the type of plant). Some thinner roots can be trimmed or will die off because of the air, and roots thick enough to survive will start to develop a nice nebari. If you are making a bonsai, I would think you would want to chop a lot of the remaining tap root to encourage wider roots at the top (nebari), thinner roots that absorb more moisture, and small leaves. I like the method in which people put a flat slab or rock directly under the plant before re-potting in order to encourage the roots to grow outward instead of downward.

...... hard to imagine what Peter has going on w/o a picture. It might be like JW suggests, that a fair portion of the trunk was simply buried, which is extremely common. The following may or may not apply, but just because adventitious roots form on a partially buried trunk doesn't turn the trunk into a taproot.

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The roots of the ficus above once extended close to a foot below the soil line (3 gallon nursery can). The shot above was the 3rd repot. More heavy root mass was removed during the subsequent repot and the tree is now in a 1.75" deep pot with good lateral roots developing.

Al

Hah, yeah no I do that too where I expose as much as the lower trunk as possible for the trees that I transplant, I've been surprised before by a juniper I brought home from a garden center, and now I make a point to check EVERY potential tree to see how far the trunk base actually goes below the soil line.

Anyway, on to the root of the subject :-P ...

You can see the start of the tap root below all those whips, it's slightly orangish... more so lower down the root, which extends the height of a pickle jar and only really begins to taper on its last 2 inches.

I'll take another photo when I lift it out, once it's better adjusted to being dug out of the ground.

So my initial concern was whether I should gradually raise it up on its tap root and keep most of the current branches, or eventually just hack all of the branches off with the exception of that larger central one while eliminating the taproot all together (which would be more work and take much longer).

Also, if I do raise it, should I encourage aerial roots to grow down the "trunk" like a mangrove, or banyan, or whatever? It's an elm and obviously not the type of tree you'd usually do that style with.

You need to define what style the tree will be grown in, establish what your trunk line is going to be and start working on getting it cleaned up. Reverse taper is already significant, so layering the tree above where it starts makes good sense ...... or plant it deeper.

Al

Layering off an ugly root system:

Al