Black locust
Robinia pseudoacacia
Early settlers in the U.S. struggled to survive when they first arrived at Jamestown in the early 1600s. Being short of food and shelter as well as facing disease, they quickly learned to use whatever the forests of their new home could provide. This is where the story of Black Locust begins.
Hard, heavy and with a heartwood that is extremely durable, Black Locust was quickly utilized for all sorts of applications. Building timbers, fence posts, boxes, wagon wheels, fenders and flooring were all made from this tree. The advent of rail travel created another purpose for Black Locust in rail ties. It was also utilized by boat builders looking for a durable wood.
Black Locust is a medium sized tree typically growing 40 to 60 feet tall with diameters of 1 to 2 feet. Exceptional specimens have reached 100 feet in height. It originally grew in an area encompassing the Appalachian Mountain Range west to Oklahoma and then south to Louisiana. It is now found throughout North America, Europe, and Asia where it has been planted as an ornamental – and for erosion control. Given its tolerance to air pollution, Black Locust is also commonly planted as a street tree.
Black locust
Black locust end-grain
Black Locust is a fast growing tree reproducing sexually and asexually via root suckers. It is shade intolerant preferring disturbed environments. It can quickly overcome prairie and savannah ecosystems creating new forests. For this reason, Black Locust is often considered an invasive species.
Black Locust is a ring porous wood with large early wood cells and distinct growth rings. The heartwood is a yellowish green to a dark brown and will darken with age. The yellowish white sapwood is distinct from the heart and is not durable. The grain is straight with a coarse to medium texture. The pores are filled with tyloses and extractives which probably give the wood its durability.
It is a stable wood with low volumetric shrinkage during drying. Black Locust can be prone to attack by beetles. Young trees can appear healthy but as the beetle infestation takes hold, the trees become stunted and fail to reach a mature size.
There is little information on the working characteristics of Black locust. Do to its small size and density it never became a popular cabinet making wood. I suspect the availability of cherry, walnut, pine, etc. relegated Black Locust to utilitarian purposes. If you do decide to work with it, its hardness and density will require sharp tools; however, it will blunt tools, so carbide tooling is a good choice. I would watch feed rates when machining to prevent burning. Nails and screws must be predrilled. Black Locust glues well and will accept all finishes. There are some concerns around toxicity. It is good advice to avoid ingesting any part of the tree and this applies to animals as well.
Black Locust is a medium priced domestic, but it is not a commercially cut timber. So if you want to work with it, you may have to do some searching. Specialty lumbers dealers are your best bet. The sawn lumber can be small, and wood derived from urban trees can be problematic due to uneven growth. There can be insect damage as well. Despite this, Black Locust would be ideal for turning projects, tool handles and other small projects where durability and hardness is prized. Black Locust doesn’t have the same fine woodworking pedigree as walnut or cherry, but it is worth celebrating for its durability and hardwearing properties.
More about Black locust
Peter Mac Sween - [email protected]
Peter's woodworking journey began with a career in carpentry followed by a decade buying and selling veneer. His spare time is spent abusing his guitars and exploring the great outdoors.
Hello M. Mac Sween,
My name is Frederic and I looking for Black locust suppliers in Ontario. I work for an urban furnitures compagny and I would like buy lot of lumbers for seating and table test. Do you have some references? Thank you