No.6 Discussion Board

South-Korea, or at least Seoul, is humid continental/sub tropical, wiki helpfully informs me. Cold, dry winter, wet, hot summer, and no spring. You're right, @lawlya, might be too tropical.
North-Korea... I kind of doubt as a setting, that would be a rather daring move if Asano consciously placed it there considering real-world affairs. Interesting thought, though. From what we know, the environment there is... not so good. Climate wise it might fit better?

Yeah, I think it's mentioned the forest in the North is natural as well. (Though wasn't the Mao forest in the North too? Was it part of the same forest or are there multiple forests?) Hm, the mountains were in the North too... though I think the forest is still within city walls. At least on the map, the airport is, and the airport was built where the Mao forest used to be. Ah, I digress, sorry.