Subject to subparagraph (B), the head of the appropriate Federal department or agency under sections
620 to
620j of this title may debar any person who violates sections
620 to
620j of this title, or any regulation or contract issued under sections
620 to
620j of this title, from entering into any contract for the purchase of unprocessed timber from Federal lands for a period of not more than 5 years. Such person shall also be precluded from taking delivery of Federal timber purchased by another party for the period of debarment.