Black Locust: The Valuable Locust, A Utilitarian Hardwood
By Jo-Ann Kaiser | Posted: 06/30/2014 11:47AM
Sponsored by: Northwest Hardwoods: Lumber that’s Graded For Yield®.
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Robinia pseudoacacia of the Family Leguminosae
Black locust, false acacia, robinia, honey locust, pea flower, post locust, yellow locust, green locust and white locust.
Tree attains heights of 70 to 80 feet with diameters of 3 to 4 feet. Weight ranges from 34 to 54 pounds per cubic foot with an average weight of 45 pounds per cubic foot. Specific gravity 0.72.
Wood is very heavy, very hard, exceedingly strong and stiff, and has very high shock resistance and high nail-holding qualities. Heartwood has high decay resistance. Wood is very durable and tough. Medium strength in bending. Timber dries slowly with tendency to distort or warp. Medium movement in service. Wood has good steam bending qualities, equal to ash and beech. Steamed wood will stain when in contact with metals. There is a legend about the tenacity of the black locust mentioned in the book Cold Mountain by Charles Frazier. Supposedly the tree has such a “will to live” that when it is cut into fence posts and anchored back in the ground as fencing, the posts grow roots and sprout limbs again.
While that may be folklore, black locust is remarkable for its qualities of strength and durability. Fence posts have long been made from the very hard, strong and heavy wood of black locusts. Poles, ties, mine timbers and stakes are also made from black locust. Other uses include wheels, barrows, wagon bottoms, boat planking, vehicle bodies, weather boards, boxes, crates, woodenware and gates.
A ‘Wannabe’ Wood
Black locust’s utilitarian roles exceed its use for furniture and cabinetry. But the wood does have an attractive straight grain that is sometimes described as “prominent.” It has been used for joinery and cabinetwork and sliced for decorative veneers, but as a furniture wood, it is described as a “wannabe” by some American veneer companies.
When first cut, Black locust, has a greenish-yellow tint which deepens to a golden color, but it is known more as a fence post wood than a wood for furniture. Some veneer companies are of the opinion that, while locust does have an interesting grain, the wood excels in outdoor uses when strength and durability are an issue, especially when wood is anchored in the soil.
The wood can pose problems when working with tools due to the coarse texture of the wood. Cutting tools should be sharpened frequently to counteract blunting. Pre-boring is recommended when nailing. Black locust glues easily and stains well.
Black locust is considered to be the most valuable of the five locusts which grow naturally in North America. Its botanical name offers a key to the tree’s identity. Robinia pseudoacacia is named in honor of a famous scientist-herbalist named Jean Robin. The name pseudoacacia refers to the fact that black locust, while similar in many ways to an acacia tree, is not a true acacia. Still, the common names of the tree in North America include acacia and false acacia.
About the Author
Jo-Ann KaiserJo-Ann Kaiser has been covering the woodworking industry for 31+ years. She is a contributing editor for the Woodworking Network and has been writing the Wood of the Month column since its inception in 1986.