Weyerhaeuser is buying Plum Creek for US$8.44 billion to form the world's biggest timberland and forest products companies. The new company will keep the Weyerhaeuser name and own more than 13 million acres (5.6 million hectares) across the United States. The total worth of the combined companies is US$23 billion based on current share prices.  The companies anticipate that the move will save up to US$100 million every year.  Under the terms of the agreement, which has been unanimously approved by the boards of directors of both companies, Plum Creek ...