User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-4452412-20130813111846/@comment-6050823-20130813221543

@Rathalosravager Is a forest open field area like the Forest and Hills.

That area could be the Unknown Sea of Trees during a seasonal change since it was said the area goes through some type of seasonal change. Its also believed from Basarios being in the Unknown Sea of Trees, it could suggest that the Underground Caves/Volcano are close to the area. Anyway looking at the area from Generu Serutasu, Rathalos, and Zinogre, this area seems like MH4's Desert like I pointed out on the map below afew comments or two pages over, though we need more info to support this.