Raene is correct, I know about Dartol's creation and the treants in the area--at least I did once. They've become corrupted now, their nature twisted.
If your goal is to find the next piece of the rod, then you'll have to find the key to open the chest it's in.
The wooden key is on one of the treants northeast of here, near Felwood. Once you have it, look for a small glade west of the road near the Felwood border... the chest should be hidden around there.
