The old times used to say that locust would last 100 years longer than stone when placed on the ground. Of course that was an exaggeration but here is a link that discusses how long the wood will last. The article state the that poles made from locust and they have lasted 150 years and are still standing.0,000 black locust trees. No thorns on the trunks. Just smaller ones on the branches. Never
Why Black Locust Beats Treated Lumber Outdoors
Naturally rot-resistant, strong, and insect-repellent—ideal for fence posts, decks, vineyard rows, and coastal builds without chemical treatment.