Robinia (Robinia pseudoacacia), commonly called black locust, is one of the most naturally durable timbers grown in Europe. It’s hard, dense and strong, with heartwood that runs yellow-green to golden-brown and darkens with age—often giving a “tropical hardwood” vibe from a temperate tree.
That durability is the headline: robinina can outperform many treated softwoods and even some tropical species without any chemical treatment, which is why it’s increasingly specified for posts, decking, outdoor furniture and structural exterior work. The trade-off is workability—sharp tooling and pre-boring aren’t optional if you want clean joinery.
Robinia is also highly tannin/acid rich, so fixings matter (stainless is the safe default). Treated with the respect you’d give a dense tropical hardwood, it rewards you with long service life outdoors and a tough, crisp feel in finished components.