Generally accepted, reasonable & prudent farming & forest practices as described in ORS 30.931 (transport or movement of equipment, device, vehicle or livestock as farming or forest practice) to 30.937 (immunity from private action based on farming or forest practice allowed as preexisting nonconforming use) DC 9.12 don't constitute nuisances under this chapter, excepting sustained noise from mechanical equipment used for heating, ventilation, air condition, odor control, fans & similar functions associated with marijuana production & processing