This quest is not available in game.
Salfa wants you to kill 8 Winterfall Shaman, 8 Winterfall Den Watchers, and 8 Winterfall Ursa. Salfa is located just outside the entrance to Timbermaw Hold in Winterspring.
The Timbermaw tend to stay to themselves, <name>. While we do allow safe passage to those we trust, we try to avoid other furbolg tribes if at all possible.
The Winterfall tribe as of late has become increasingly hostile towards us. They seem to be in a state of rage, completely engulfed by their own fear and hatred of anything they do not understand.
I must ask you to thin their numbers as to lessen the threat against us. Seek them out in Winterfall Village, far to the east of here.