I just got Steam achievement Treehugger (Went through Living Forest not attacking any trees.) by going through Dwarven Halls and ascending to forest from below and straight away descending back below it. Apparently the achievement is granted if you have not attacked any animated trees during the game and you descend the forest's stairs.

I suggest changing the achievement text to "Went through Living Forest not attacking any trees during the quest from dwarven elder." If it's possible the achievement should also check if you have the quest active when descending. This would prevent people getting it by just entering and exiting if they went through DH.