Weyerhaeuser Co (WY.N) will purchase Plum Creek Timber Co Inc (PCL.N) in a deal announced on Sunday that the two companies said would create a $23 billion timber, land and forest products company, the largest in the United States. The new company, which will keep the Weyerhaeuser name, will manage more than 13 million acres of timberland that will allow it to drive economies of scale and capitalize on the U.S. housing recovery, the companies said.