This is really cool and very interesting!

The paper texture displacement adds a lot to the effect of the forests. As a test of this process I think this is a success, but I would be interested in seeing if there is a way to get a bit more definition on the edges of the tree shapes, but keeping the shadows somewhat blurred. It seems that when the trees are by themselves or more sparse they maintain a more defined edge, but when they get more dense they seem to blur out a bit, although this may just be my eyes not being able to pick up the detail when there are more trees.

As far as the other map elements go, in the last image you have the cliff and keep/castle, which I think is effective, but definitely discernible as 2D still. That said, I like the way it looks and it may just be a different style of using the 2D elements. Sort of like a pop-out map instead of isometric.

Just as a final thought, the forests you made really remind me of Age of Empires I style rendering. I always thought that style was cool and you seem to have replicated it in a black & white/sepia tone.

Also, I would definitely be interested in a tutorial of what you figured out.