ProcedureEditWalk to the center of Whisper Hollow. Near the pond is a tree surrounded by green crystals (big decorative objects, not collectable Green Crystals). Approach this tree to finish the quest.
"Tyrah: More green crystals coming up through the ground? Fascinating... I may have you go back and get me samples."
"Tyrah: Keep moving north, Banshee Peak is one of the higher points on the island, and should give you a good view of what is going on."
Access Quest 6: Climb to the summit of Banshee Peak