Shadow Isles Transformation

So I started reading through 's lore to brush up on some Shadow Isles stuff.

"For ages, pain and grief were the only companions the spirit had. His boughs grew heavy as he wept at the desolation of everything he had known and loved, and his roots tore from the earth as he raged at the reckless sorcerers that had ruined his home."

So I'm left wondering: as everything is being destroyed around him, would any lore geeks or lovers of Shadow Isles have any idea of a timeline for this destruction? All happened in hours, days, instantly? From a writer's perspective and having a thing for tidy timelines, thinking this on my own is driving me a little crazy, lol.