Black Locust

What is black locust?

Robinia pseudoacacia, or Black Locust is a tree species native to the southeastern United States.  In fact, because it is a fast growing tree, it is considered by many to be invasive, however, the wood has many fine characteristics: not only is black locust a very dense

Locust Wood Forest, Newfield, New York March 2012

and heavy hardwood, but it is durable and very resistant to decay.  The tree   contains falavonoids which gives it a superior ability to resist decay and thus, the wood can endure hostile soils for over  100 years.

It is the most decay and insect-resistant of any North American wood.  It consistently ranks in the top 5 % of all structural design standards in terms of strength, shear factor, elasticity, compression and bonding.

Check out the USDA Fact Sheet on Locust Lumber,


Tree of Opportunity

Freshly-cut locust wood

Black locust is generally regarded as a tree of opportunity because it is one of the first trees to populate abandoned land.  It grows surprising fast and when grown on good soil, produces high quality lumber, and produces it  faster than any other hardwood.  It has the ability to regenerate after cutting into a superior quality second and third generation as its new growth come from rizomes from the harvested parent tree roots.


It should be obvious by now that black locust, because of its longevity in hostile environments (the soil) and ease of reproduction, is an exemplary and sustainable wood.  In addition, it weathers very evenly to a consistent light gray color.

Black locust wood is probably the most underrated hardwood.  It has been used for centuries in the most unglamorous and adverse conditions and it still stands up to its reputation of durability and strength.

Other Technical Data

MECHANICAL Compression Dry:
Janka Hardness: 1,700 lbs.
Parallel: 10,200 lbs. /sq. inch
Shear: 2,480 lbs./sq. inch
Perpendicular: 1,830 lbs./sq. inch
Modulus of Rupture: 19,400 lbs/sq. inch
Modulus of Elastic: 2,050,000 lbs./sq. inch
Specific gravity: 0.69
Average Dry Weight: 51 lbs/ cu. Foot
0 % MC 6% MC 20%MC
Radial: 4.6% 3.7% 1.5%
Tangenital: 7.2 % 5.8% 2.4%
Volumetric: 10.2% 8.2% 3.4%


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