In North America, the maple species are divided into two groups: soft maple (which includes red maple, Acer rubrum, silver maple, A. saccharinum, and bigleaf maple, A. macrophyllum) and hard maple (which includes sugar maple, A. Saccharum, and black maple, A. Nigrum). Once the lumber is manufactured, it is possible with 10x magnification to separate hard maple from soft maple as hard maples have ray cells of two different widths (seen from the end grain) while soft maples have one width. Soft maple also tends to be softer, lighter weight, weaker and dingier colored than hard maple.
Of the two main soft maples, red maple is about 10 percent harder and 15 percent heavier than silver maple. Red is also stronger and stiffer than silver.
Red maple grows throughout the East Coast, from Florida to Newfoundland and west to Texas and Minnesota. It prefers wetter sites, but grows in a wide variety of climatic and soil conditions. Trees are typically 70 feet high and 24 inches in diameter at maturity.
Silver maple also grows along the East Coast, but is not found commercially in Florida, Louisiana or Texas. The trees are a bit taller and larger in diameter than red and have the largest winged seeds of all the maples.
Although not as strong as hard maple, the name “soft” gives the wrong impression. Soft maple is more than adequate for many uses, including furniture, flooring, cabinets, kitchenware, clothes hangers and the like.
Red and silver maple also can be used for syrup production, although the good sugar season is earlier and shorter and yields are less than with hard maple. Wildlife also like to browse the trees for food.
Processing suggestions and characteristics
Density: Red maple weighs about 36 pounds per cubic foot at 7 percent MC. This means that a piece of lumber planed to 3/4 inch will weigh 2-1/4 pounds. Silver maple weighs about 31 pounds per cubic foot at 7 percent MC. Dry, planed lumber will weigh just under 2 pounds per BF.
Drying: There is little risk of checking and warp with proper stacking and drying conditions. Slow drying can develop stain, both fungal and chemical, so aggressive drying ASAP after sawing is suggested. Dry stickers are also essential. Shrinkage averages about 6 percent in width for flatsawn lumber and 3 percent in thickness.
Gluing and machining: Red and silver maple are excellent gluing woods and are very easy to machine. Due to the softness of the wood, very sharp tools work best. Avoid moisture contents over 8.0 percent MC for best machining.
Stability: Soft maples are less responsive to humidity changes than hard. For flatsawn lumber, a 4 percent MC change results in 1 percent shrinkage or swelling. In the radial direction, an 8 percent MC change results in 1 percent size change.
Strength: Red maple has an MOR of 7700 psi, an MOE of 1.39 million psi and surface hardness of 700 pounds. Silver has an MOR of 5800 psi, MOE of 0.94 million psi and hardness of 590 pounds.
Color and grain: The grain is very fine textured with white sapwood. Heartwood is buff colored to darker brown.
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