Wow - thanks for all of the interesting and helpful answers. Now I have a much better sense of what what people like about this style, and I think I even have a better sense of what it is that I like and don't like about this style.
A few comments. First of all, just so that we're clear on the technical terms
, buttressed roots aren't oil slicks. Large roots over rocks aren't oil slicks. Massive twisted roots aren't oil slicks.
This is an oil slick:
It's not the worst I've seen; there are some pretty horrible beeches and especialyl stewartias. Basically, by an oil slick I mean a tree with a root base that abruptly shifts from approximately vertical to approximately horizontal and spills out in one disc-like fused mass across the surface of the pot.
Tony's completely right - one certainly wouldn't want to try to correct the oil slick on that triple-trunk (quintuple trunk?) maple shown. Just as I wouldn't necessarily bother to try to correct for the larger foliage on my European beech by grafting Japanese beech onto every branch. That doesn't mean that the bigger foliage is desirable, just that in this case you're pretty much stuck with it.
Al's virtual is very interesting. I have to admit, the tree looks worse without the oil slick! Why?
I think it's something about the fused trunk bases as well. They don't join at the ground; they join quite a bit above this. To me (and this part of why I don't like the style) it almost looks as if the tree was created by a brutal chop followed by growth of several shoots. I know it wasn't fashioned this way, but in opinion it doesn't look all that much better.
So it seems that an oil slick actually helps when you've got fused-base multi-trunk trees. I learned something from that, because I wouldn't have guessed it a priori. Thank you, Al.
Would the trident shown here also look worse if you took away the oil slick? I bet not, but I'll try a virtual once I get the chance and then we can see for ourselves.
---
Finally, the question I've always wanted an answer to: is
nebari singular, or plural? Please help! Until I figure that out, I can't use the word in a sentence.
All the best,
Old Mister Crow