This is pretty
So I'm concluding the over all atmosphere of this artwork is "sadness", right? You did great in expressing sadness through the shedding of the leaves. The sadness expression can also be seen with the tree left all alone in the top of that tree. (TT.TT)
Here are some of my opinions for you to be able to express "sadness" more effectively and more emotional (it is already emotional at that, btw): First, maybe you should darken the blue background a bit? Maybe change the setting to dusk. Because mornings with blue sky is always associated with beginnings and happiness. Second, the color of the grass and most of the leaves of the tree should be brownish to enhance the feeling of fall or autumn; autumn colors are always associated with sadness too.
Well, that's that
Keep up with the good work!