The goblins in the Living Deep use barrels of black powder to destroy the forest from below.
'Goblins are clever creatures, dastardly in their approaches to war and the battlefield. Unlike the Orcs who walk about within the forest itself, the goblins have taken to the caves and are destroying the forest from below with their sorcerous black powder.
'The goblins plant the barrels, then the soil explodes out and the trees fall into the tunnels below. They are then dragged to feed the Enemy's war-machine. The forest cannot defend itself from this destruction.
'Head into The Living Deep, find the black powder, drag it to a safe place and destroy it.'
Powder-kegs can be found within the Living Deep.
Dernstan asked you to venture within the Living Deep and safely destroy the enemy's black powder.
Dernstan is at Eaworth.
Dernstan will be pleased to hear you have safely destroyed several barrels of black powder.