Forest products giant Domtar Inc. is buying four American paper mills from Georgia-Pacific Corp. The $2.5-billion deal will transform the Montreal-based company into the third-largest producer of uncoated freesheet (photocopy and printing papers). G-P is selling four mills and pulp facilites in Ashdown, Ark.; Nekoosa and Port Edwards, Wis.; and Woodland, ME.; to reduce its debts and focus on paper-based consumer products. The deal is expected to close early in the third quarter.