Maine's 17.7 million acres (7.2 million hectares) of forest in 2002 contained over 3.6 billion trees and covered 90% of the state's land area, the largest percentage for any state in the US. About 16,952,000 acres (6,860,000 hectares) are classified as commercial timberland, over 96% of it privately owned, and half of that by a dozen large paper companies and land managing corporations. Principal commercial hardwood include ash, hard maple, white and yellow birch, beech, and oak; commercially significant softwoods include white pine, hemlock, cedar, spruce, and fir. Total lumber production in 2002 was 988 million board feet, of which 89% was softwood.