It's quite hard to tell without seeing the rest of your game (like the floor, the tree will be placed on).
Personally, I would try to draw bigger leaves in order to avoid too much chunks and prevent the dithering (but that depends on your preferences). In my opinion, you could try adding a colder color (blue) to the shadow. That should fit to the ground as well, which is hard to tell without seeing the rest.
All in all I like the texture.