I gathered the bark with no problem, but am confused about its purpose.other than causing the ancestor moths to swarm you(?) does the stuff serve any other function?
It's jut a quest item, so no. Ancestor moth wing is an alchemical ingredient, so it remains useful, but unfortunately ancestor moths attracted by canticle bark aren't harvestable, so it's not even useful for that purpose. You can drop the draw knife and canticle bark after completion of the quest.