Hi Cardenaglo, I'm no expert, I'm just learning myself, but I've tried using these same brushes before. I'm gonna get a bit nit picky on you so I hope I don't over step my bounds, I just see so much potential here, and much room for improvement.
In regards to you're trees, I prefer the areas where you've stamped them more closely together, it kind of hides the repeating nature of stamping brushes over, and over. If you find there seems to be too many in a particular area maybe try putting a layer mask over it and remove some of the trees here and there to thin them out a bit, or make them flow with the land form a little better.
In the areas where there’s less trees, or a single stamp you could try adding individual trees around the edges to extend them a bit or change the shape of the cluster to hide the repeating pattern of the brush. You could even mask out some of the trees on a single stamp to make them fit better within a particular area, or subsequent stamping.
Don't be a slave to the brushes, I find you have many areas where you're stamping overlaps other elements, or just doesn't fit you're land form, I even see areas where you've stamped over top of the coast line, and into the water... This can be easily remedied by adding a layer mask, or erasing the areas that overlap.
Some of your mountains, and roads just touch the coast line, I would move these in a bit.
I also feel like your coastline could really benefit with some more contrast between the land, and the sea. I would love to see a more definite outline on the coast, or maybe even a darker blue around the edges, or some wave lines. I think it would better match the hand drawn style of the brushes... And in regards to that, I think the definite black you've chosen for the icons is too dark, and makes the back round look washed out in comparison. A nice brown would look good, or you could even just lower the opacity of the icons a bit to make them a bit less stark.
One last thing is I think the composition of this map would look much nicer with a portrait orientation instead of a square, I find the top, and bottom coast is too close the edge of the map.
Sorry again if I went too far, or rambled on too much in my critique, but again I see allot of potential for this map, and I can't wait to see it progress. It look's like you've put allot of thought into the history of the people who live here, it would be interesting to know more about the cultures you've created.