The Au Sable State Forest is a state forest in the north-central Lower Peninsula of Michigan. It is operated by the Michigan Department of Natural Resources. The Au Sable State Forest is a byproduct of the lumbering boom in Michigan during the late 19th century. Many parcels of old growth timber were stripped of their largest trees. After forest fires had consumed the resulting detritus, the land had no economic value. Typically, it was sold to subsistence farmers or was reverted to the state in lieu of unpaid property taxes.