I have created another sub-biome called the dark woods which will reside mostly around the lake area.
there are some smaller patches of darkwood trees scattered around the edge of the map, where the mountains are to make the map look more as a whole rather than 5 different sections of biomes.
Here are some screenshots of the map overview.
Here you can see that this type of biome keeps the trees more in clusters rather then spearding them out evenly.
Also as a refresher I recreated the layout of our map since a lot of changes were made.