This looks really rad in the preview; I think what's missing from the crown is shading. Roughly speaking, the crown of a tree would have similar shading to a sphere (with some clumps of foliage casting local shadows), but this is pretty flat.
Would you mind if I tried playing around with it? (no guarantees that I'd get around to doing so, har, har)
really really nice, clean and stylish as i like it.. (or for my pixeljoint.pl friends: cudowny! ja lubie jasne styl! sorry for bad grammar =)