I think you need to read my post again.,,,I said "Or unless You are dumb enough to use pressure treated lumber."
Pressure Treated Lumber not black walnut shavings. I really don't know how you got it confused. So for the record I did not call you dumb, dunk. Pressure Treated Lumber should never be used for mulch or not even burned, the smoke is poisonous. Most pressure-treated lumber sold before January 2004 was treated with chromated copper arsenate (CCA for short), which contains arsenic.
http://www.co.thurston.wa.us/health/ehhm/cca.html.
It just won't kill plants, it kills humans and animals. So I think anyone would be dumb to make mulch/shavings from Pressure Treated Lumber.