I happen to agree with you. I think the setup is looking really good. But the tree does need work. I think you need to add the extra yellow shade used on the tree trunk to add depth. As for the leaves, they are really dark and seem to be useing an entirly differant lighting level to the grass which is utilises the lightest shade the most. I think the tree would benifit greatly from you makeing the leaves much lighter so that they are brought foward and match the intensity of the grass.
