The bark looks more like a plastic bag, however, there's an easy way to fix that. IF you insist on the barking having a shine, try making it at least a little less contrasted from the base next-ligthest colour, bark doesn't shine or glow IRL. The leaves look terribly flat, which is a shame, cuz the trunk is well-made texture wise. I suggest you add some shadows here and there and maybe draw leaves instead of a mixture between a light and dark green.

This is awesome, the leaves are great.

I really like the little bird.

For the rest you should really look up some more references, especially how trees tend to grow and how this shows in their texture / bark.

I like the trunk, but the leaves look so flat. Its probably because of the black outlining all the way around, and its not really shaded, just textured.

Aha, sorry! I think it's just how smooth the shading is and the various shapes look as though they are folding. Perhaps having a more rough texture and sharper contrast, while toning down the creases could help. Though, this is quite nice eitherway.

 Ogosh..now that you mentioned it i can't unsee it D: lol could it be the highlight that's making it look too silky? 

Heh, looks interesting. The shape and texture of the roots look like silky cloth. :3