Black Locust
Robinia pseudoacacia · Hardwood
- Type
- Hardwood
- Origin
- Native to the Southeastern United States; widely naturalized throughout North America, Europe, and Asia.
- Hardness
- 1,700 lbf (Hard)
- Durability
- Very Durable. Exceptional resistance to rot and decay; known as one of the most durable timbers in North America, frequently surviving 50+ years in ground contact.
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Grain Pattern
Straight to slightly interlocked grain with a medium to coarse texture. Exhibits prominent cathedral patterns in flat-sawn sections and visible small knots/bird's-eye features common in live-edge slabs.
Color & Appearance
Heartwood is pale greenish-yellow to golden brown, while sapwood is a distinct thin band of pale yellowish-white. It darkens to a medium-brown with age and light exposure. Highly lustrous and exhibits strong fluorescence under UV light.
Hardness (Janka)
1,700 lbf (Hard)
Durability & Decay Resistance
Very Durable. Exceptional resistance to rot and decay; known as one of the most durable timbers in North America, frequently surviving 50+ years in ground contact.
Value & Sustainability
- Estimated Market Value
- $6.00 - $12.00 per board foot for live-edge slabs, depending on width and figure.
- Wood Age Estimate
- Freshly milled or recently harvested (under 1 year). The light greenish-yellow heartwood indicates little oxidation or long-term UV exposure, and the bark remains very tight and intact.
- Sustainability Status
- Not listed on CITES Appendices or the IUCN Red List. Categorized as a species of least concern; widely available and fast-growing.
Common Uses
Fence posts, outdoor furniture, decking, timber framing, tool handles, boat building, and railway sleepers.
Geographic Origin
Native to the Southeastern United States; widely naturalized throughout North America, Europe, and Asia.
Workability
Difficult to work due to high density and hardness. Dulls cutting edges quickly. Glues and finishes well, though pre-boring is required for nails and screws to prevent splitting.
Finish Recommendations
Oil-based finishes (like Tung or Danish oil) highlight the natural golden hue. For outdoor use, high-quality UV-inhibiting spar urethane is recommended, though many leave it unfinished to weather to gray.
Notable Features
Glows bright yellowish-green under blacklight (fluorescence); high rot resistance makes it an eco-friendly alternative to pressure-treated lumber; contains specific toxins in the bark and leaves (though wood is generally safe).
