Druids currently have 7 trees. (And a treeent form)
1 class tree, 4 spec trees and 2 (or is it 3 for druids?) hero trees. Only 3 can be used at any one time though (to be clear as you don't currently play)
The more possible combinations, the harder it can be to balance though
I mean, my understanding is that they fired half of their story continuity team, resulting in a published (physical) lore book that makes no sense.
So now I don't think they are even trying