[Flyndaran]

Originally Posted by Apollonian

Eh... I'd probably set up some big campaign arc about a necromantic blight afflicting the trees and the quests to figure out how to stop it. Given my players, they'd be a mix of halflings and centaurs. Probably have the blight be a false-flag operation conducted by someone trying to spark a war between the woodsfolk and the plainsfolk for Reasons.

Also might lean into the colossal trees bit and go with actual mountain-sized trees, and use a couple of them as living cities for the halflings. I like my fantasy to be pretty fantastic sometimes.

Don't necessarily need magic to cause problems. Living trees likely have predators or parasites. Anomalously frequent infestations could add some intrigue to the campaign.
Of course magic could magnify mundane threats.