I said this before but the forest around Mt St Helens grew back in 10 years, I don't think 5 years is out of the ordinary.
I'm referring to the lore SE has established, not some hater-generated theory. They're the ones that said that part of the mystery that managed to subdue Bahamut is also part of the reason why everything recovered so quickly.
So, yeah. While I'm well aware that flora and fauna recover fairly quickly from disasters, SE said there was a reason behind it.
All I'm saying is it's probably directly tied to the dramatic increase in breast sizes we are most likely to see. :3