Sap of Sosaria-Help Needed

Thought i would give the Human to Elf quest a try, but i seem to be stuck, i
have accepted Strongroots Quest, but when i go to the place where the sap is
supposed to be there is nothing there, i have waited, searched quit the
quest and restarted it, but i still cant find the Sap.
Any help would be much appreciated.

Karr -Lake Superior