These are some table-scrap trees I've built. It's not something that normally interests me, but I found the large foliage pieces in the PaB wall and decided to fill a large cup. The left one is my first attempt at a tree from about a year ago. I wasn't terribly happy with the way all the foliage is perfectly horizontal. The one on the right is my recent attempt at something more organic. I don't have any brown arch pieces for the branches, so I had to use black for the moment. If I ever integrate this into a full MOC, I'll order some. I'm also scraping the bottom of my PaB cup of foliage elements, so I'm not going to finish a forest any time soon. Anyway, aside from the difference in trunk structure, the big difference is that I bent the foliage pieces so they curl downwards naturally. They seem to use a similar plastic to the flexible bar sized tubes, so bending them doesn't seem to cause stress.
Side view. the one on the right could use a little more foliage to fill it out, but at least it doesn't have the look of stacked plates like the one on the left.
The bottom of the large tree uses an offset stack of arches on the bottom, and then this nearly symmetric structure of 3 branches on the top. I'm trying to avoid having branches jutting out at right angles because it looks obviously inorganic. Any regular pattern at all seems to ruin the effect. Maybe my next tree will use bars inserted into technic click hinges for the branches.