Trees are always incredibly hardy to do. Great joby with this!
Mmm. thanks for the comment 
, I'll try the dithering for this tree, I was searshing for a real detailed tree but my problem are the leaves, it's so hard to bring them to life. 
It's a nice piece but I would work on the shaded area, you have a piece of art called "Sky_boss" which uses the dithering technique, it would be best used on this piece
I agree with ADrawingMan, trees can be hard to do, I certainly find them one of the tough objects to tackle in this style but you are so on the ball with this piece, it's just that little bit of dithering can make the world of difference. You have a lot of potential