ok
thanks Helm for the hint
I did a major rework on the ramp tones and came up to this:

I'm working right now on the shade of the tree and as you can see the lower part is actually well integrated.
I also added redish pixels on the temple to give more light to it.
there're some colors that are very similar and I'm not sure to merge them into one
still to be done: the top part of the tree, the sky and the leaves on the background. and some small things on the bottom part.