(a) The department may issue a permit under this subchapter, as an alternative to a permit issued under § 623.011, authorizing a person to operate a vehicle or combination of vehicles that is being used to transport unrefined timber, wood chips, or woody biomass or equipment used to load timber on a vehicle in a county identified as a timber producing county in the most recent edition of the Texas A&M Forest Service’s Harvest Trends Report as of May 15, 2013, at the weight limits prescribed by Subsection (b).
(b) A person may operate over a road or highway a vehicle or combination of vehicles issued a permit under this section at a gross weight that is not heavier than 84,000 pounds, if the gross load carried on any tandem axle of the vehicle or combination of vehicles does not exceed 44,000 pounds.

(c) § 621.508 does not apply to a vehicle or combination of vehicles operated under this section.
(d) The department shall annually update the number of timber producing counties described by Subsection (a) based on the most recent edition of the Texas A&M Forest Service’s Harvest Trends Report.