Only 5 years?

No, no, no. Wrong. Unless trees grow as fast as the common weed, there's no way that The Black Shroud is going to become a new forest after only 5 years after a MOON crashes into the planet. Also cities. Entire cities rebuilt after 5 years? Unless every person in all of Eorzea dropped everything and built the new cities from the ground-up for 24/7 in day/night shifts, no way are entire cities going to be rebuilt in 5 years. Especially Limsa, which is levitated above rocks and water.

While having only a 5-year skip is fine since our favorite NPCs will probably survive (Merlwyb and Hildebrand), it just makes no sense from a geological standpoint.

Yes, a lot can happen in 5 years, and assuming they could rebuild civilizations in 5 years, that doesn't excuse the plant life. Have you seen those trees? They look like they've been growing for over 100 years.