My grandfather's land in the mountains of NC is Covered in Black locust. The trees seem to die off when they get old, but they seldom fall, so we call them standing wood piles. They are not terrible to split, especially if its real cold out, but they are very hard on blades, and have a propensity to check and warp, making them a poor choice for lumber compared to some other species. They make great posts, and of course are fantastic firewood. Here's one of our piles up there from this past summer. The layer you are looking at is the 4th later depth wise. We can normally go 5 before blocking the light.