(a) The gross receipts or gross proceeds derived from the sale of machinery, new and used equipment, and related attachments that are sold to or used by a person engaged primarily in the harvesting of timber are exempt from the taxes levied by this chapter and the Arkansas Compensating Tax Act of 1949, § 26-53-101 et seq.

(b) The machinery, new or used equipment, and related attachments are exempt under this section only if they are:

(1) Purchased by a person whose primary activity is the harvesting of timber; and

(2) Used exclusively in the off-road activity of harvesting of timber.

(c) The exemption provided in this section does not apply to a purchase of a repair or replacement part for the machinery, new or used equipment, or related attachment.

(d) As used in this section:

(1) "Equipment" means only complete systems or units that operate exclusively and directly in the harvesting of timber;

(2) "Harvesting of timber" means the use of off-road equipment and related attachments in every forestry procedure starting with the severing of a tree from the ground through the point at which the tree or its parts in any form have been loaded in the field in or on a truck or other vehicle for transport to the place of use;

(3) "Machinery" means only complete systems or units that operate exclusively and directly in the harvesting of timber;

(4) "Off-road equipment" means skidders, feller bunchers, delimbers of all types, chippers of all types, loaders of all types, and bulldozers equipped with grapples used as skidders; and

(5) "Primary activity" means the principal business activity in which a person is engaged and to which more than fifty percent (50%) of all the resources of his or her business activities are committed.