They were there when I bought the place. They had taken over some areas that had become no go zones due to their thorns. Cutting them down only encourages them unless you follow up with animals and or mowing with machines. Ruminants LOVE black locust leaves. Cattle will eat only so much in one go. Goats will eat them 24x7 if they could. Best succes in eliminating them I had was to cut trees then graze with goats for a year. Second year I put pigs in to disturb roots. That seemed to do them in.
In their place they are a great tree. I have some in open fields. Cattle keep the new shoots under control. I pollard a third of branches each year on each tree and feed to beef. Branches make excellent
kindling. Wood burns very hot and long. A very desirable firewood.
Ive used them as fence posts. Its true the heartwood is rot resistant but the sapwood is not. The wood is very hard which makes driving nails when fencing difficult. I prefer to use eastern white cedar (thuja occidentallis) for fencing since it is a softwood and takes a nail so much easier.
In early June my homestead smells of jasmine and the sound of bees buzzing fills the air.
I still plan to plant rows of BLs as a silvopasture to fix N feed my honey bees , my cattle and my wood stove.
Best Regards and feel free to ask any question about this sonewhat controversial tree.