Black Locust (with possible identification as Osage Orange)
Robinia pseudoacacia • Hardwood
Grain Pattern
Usually straight or slightly interlocked; showy ring-porous grain structure with distinct annual rings and prominent rays visible in the end grain.
Color Description
Heartwood is pale yellowish-brown to greenish-olive, darkening to a golden brown with age. Sapwood is narrow and yellowish-white. It exhibits a high natural luster.
Hardness Rating
1,700 lbf (Hard to Very Hard)
Durability Rating
Very Durable; exceptional resistance to rot and decay, often used for ground contact without chemical treatment.
Common Uses
Fence posts, boat building, outdoor furniture, decking, mine timbers, and firewood (high BTU).
Geographic Origin
Native to the Southeastern United States; widely naturalized throughout North America, Europe, and Asia.
Market Value & Sustainability
Estimated Market Value
Approximately $4.00 - $8.00 per board foot depending on grade and region; often higher for specialized rot-resistant use.
Wood Age Estimate
Based on ring count and oxidation of the fresh cut, the branch/log is approximately 15-20 years old and has been drying for several months.
Sustainability Status
Least Concern (IUCN); widely available and not CITES listed. Often considered invasive in some regions which aids FSC availability.
Workability
Difficult to work due to extreme density and hardness. It has a high dulling effect on cutting edges. Turns well but can be prone to checking or splitting if not seasoned carefully.
Notable Features
Highly fluorescent under blacklight (yellow-green). Contains high concentrations of water-soluble extracts that provide its rot resistance. Very heavy and dense.
Finish Recommendations
Takes oil and wax finishes well. Due to its natural oils and density, film-forming finishes like polyurethane may have harder adhesion unless surface oils are wiped with solvent.
Identification Confidence
High; the distinct narrow sapwood, golden-greenish hue of the heartwood, and deeply furrowed bark are classic indicators of Robinia pseudoacacia.