How about no trees at all? Instead create a different g-map that plays on the earth lol. Or bring Skyworld down to earth, and connect places and towns to Skyworld

Xenoblade Chronicles X's world is awesome. Maybe try implementing something like that?

Skyworld is one giant city surrounded by borders. Outside the borders are towns, creatures to hunt, gigantic map to explore. The tileset outside the borders shouldn't be futuristic but wild. What I mean by wild is grasses, trees, dirt, mountains, forests, etc.