Cinaid knows that the eagles to the east are defenders of the land and friends to nature. To make them a natural enemy for your sapling, will be a great boon.
'To the east, in the shadow of the Isendeep Mine, there are eagles that soar and defend the land.
'There, where Arador fell, you should travel and gather the feathers of those terrible creatures. We will use the quills as lances to stab the flesh of your sapling. It will learn that the feathers cause it pain and animosity will seep into its heart. In time, it will learn to attack the eagles and their allies on sight.'
Head to the east, in the shadow of the mountain that houses the Isendeep Mine, and hunt the eagles there for their feathers.