This is just a thought on the matter, but if you have a greyscale version of that first map showing just the pure relief with nothing else, you could try putting it over the top of everything else you draw in this second map, and using an overlay mode on that layer. The effect, I imagine, would be to give the map a very subtle sense of relief. It wouldn't show very much, but it would be there - either overlay, or multiply.
I really like those trees![]()