Looks good! That small tree is exceptionally well done. With the bigger trees, however, there's room for improvement. First off, you need to add twigs. What you used as a substitute for twigs are branches (the prefab element). No tree starts off with thin branches - at the beginning, thick twigs almost the size of the trunk itself grow out of the tree. Try inverted brown slopes! Don't get me wrong, the prefab element you used is great but I would advise to use it at the end of twigs rather than a replacement for them.
About the bending of the tress: I personally don't like it. Could be just me, but I don't have feelings towards such flimsy structures. If I wanted a tree whose trunk isn't completely straight, I would either do the trunk with a brickbuilt slant or just use a hinge at the base. Your solution does look good and is creative, though, I have to give you that.
The mud is something I also like about your creation, Masked Builder. Looks very authentic. To supply some constructive criticism, the edges are a bit too straight and angular - if you know what I mean.
Another great thing is the elf, of course!
Overall, I find this to be a very nice little vignette, Mr Masked. Your small tree has brought inspiration to my mind.
Cheers!
Enpaz