Hello, first of all, thank you for all your comments; my English is very bad but I as even will try to answer you ( thank to the software for translations ).
The concept of the island was to make a relief dedicated to the special units like the troops of mountains, etc...
I mixed sand textures with grass textures to give the illusion of the acid grounds on which the pines grow.
For the moment, I did not put roads between north and the south because I wanted to make two separate government but since many people me require it, and if I find time, perhaps which I would make connecting a road the south to north.
However, it be certain that if I remake a island, the next time it be less large; indeed, it is very tedious to pose 70000 trees or bushes when you are alone to work
Still thank you for your encouragements  Â
Narpal