This unique tree presents an interesting question: How to deal with material that has a lot of visual interest located fairly high up on the trunk?
It looks as if this tree was growing between stones and the straight section was protected by them, with wind, snow and ice affecting the exposed portions?
Mr. Kimura deals with a number of junipers with similar characteristics in a unique way: using his "upside down" technique, he strips away much of the inactive xylem, leaving just a flexible ribbon of living tissue. In this way he can bend the tree back to the earth to eliminate the straight, relatively uninteresting portion.
A drastic technique like this, that works so well with even aged juniper probably would be unsuccessful with a pine! Other options like layering don't appear very likely to produce desireable results, but I don't know how the Mugho responds to layering, especially at such an old age.
Another technique covered in the bonsai today a couple years ago covered the grafting of large Japanese Red Pine to reduce its height. An approach graft was made with a tree of comparable size and the two trunks were dovetailed together. Once the union formed, the trunks were separated slowly, to leave a shorter tree.
FORESHORTENING
A line segment seen in perspective appears to be shorter visually than one that extens across the visual plane.
John Naka restyled a large oak shown a few years ago at GSBF convention by bringing it directly forward over the pot. The trunkline itself blocks a large portion of the straight, uninteresting trunkline from view. I can't quite tell from the picture whether a cascade or half cascade would even be possible. Perhaps a photo taken from another angle would be helpful.
EXPOSED ROOTS
Another question is whether the arrangement of the roots are fully understood. Often when a trunk is twisted so vigorously, a similar pattern might be seen in the roots. Is this the case with this specimen? Is the arrangement of the roots known?
DIAGONALS
Diagonal lines appear to be more dynamic than horizontal or vertical ones, and might be one way to create visual interest in the straighter portion of the trunk. An idea might be a kind of serpentine trunk which rises out of the soil at about 45 degrees and then bounces along it in the knotted ball could be used to create a convincing bonsai from a tree, by disguising the straighter portion as a diagonal.
OBSCURE
Hiding the straight portion of the trunk with foliage is sometimes an option when it occurs higher up on the tree. With this specimen, it doesn't appear to be a completely viable option, though, but sections of foliage could be brought across parts of the straight trunk to break up the line, in any case.
This is a very unique tree, and I will look forward to following its progress as a bonsai!
Regards,
Matt