All quest groups (diads or triads) start with the Main, non-repeatable quest, which unlocks the repeatable quests.
Almost, but not all, diad/triad repeatable quests can be performed and turned in at the same time. This is one that can.
Quest Type
Needs
Main
Use Ritoloya's Lute to play music to calm the minds of 10 Angry Tree Spirits
Daily
same as Main
Public
same as Main
Notes
Spoiler Alert! We have hidden this information so that you have the choice to try it on your own, or have the advantage of knowing how the sausage is made...
There is no damage threshold for this, but there is a maximum distance requirement. So smack the Ent to bring him to you, then start clicking the lute. As soon as he is close enough it will start casting.
Daily Quests are repeatable up to a total (for all Daily Quests) of 10 times per day. The count can be reset to zero by purchasing and using a Daily Quest Ticket from the Item Shop (for 39 ($1.16)† ) or from any Phirius Merchant (for 780 ).
In all other zones they do not reward XP, TP or Gold, only Public Event Points. In all other aspects they are the same as a Daily Quest (except for the infinitely repeatable part and the rewards). Public Event Points contribute towards the completion of Regional Quest objectives, which in turn rewards a number of Energy of Justice commensurate with your amount of participation in the Regional event.
Daily Quest Ticket from the Item Shop (for 39
($1.16)† ) or from any Phirius Merchant (for 780
).
Dual-Function Daily Quest Potion.
Old Bag (hence the common sobriquet, Bag Quests). In Redhill Mountains, each repetition of [67][Public] Freedom Fighters rewards an 
Ancient Memento.