[ The fauns must've also fallen a bit out of the ways, then, given the way Hilda reacted to his abilities. It's not really mentioned very often that there were natural caretakers of such things. Not hidden either. He's sure that if he looked, there would've been plenty referencing that. ]

It's more than possible. I'm used to it having been done in my world, but Hilda confirmed that it happens here. It takes a lot, but it's not hard with the way those types of feelings and overall mood can start spiraling out on its own. Dark spots that develop on the surface easily sink into the earth. Wars and rebellions are good for that kind of thing, but oppression, strife and other similar things could feed into this if it smothers those trying to live on and try to have more than just that in their lives.

[ And yes, he's very used to these things. Sowing discord and resentment, to lead into civil wars or mass deaths were a particular group's specialty. ]