I can vouch for the use of BlackLocust for posts and firewood. Built several fences with my dad as a teenager and have witnessed the coming and going of other fence posts while most of the locust fence lines are still solid. Over 60 years for those. they tied into fences that were old when I was young. Those were locusts and some of them are still standing as well. I recall some folk lore wisdom about best time to cut them and when to set them, forget what any of that was, I wasn't interested in most of the wisdom of the day. If it had a steering wheel I was interested.
Fast forward, when I built my own place near Lawrenceburg Ky during the Arab Oil Crisis, 1973 era, I bought an airtight stove and heated the house with wood. I always had heard that oak and ash were the good firewoods and felt like a poor second class citizen since all I had was acres and acres of black locust. Had to do very little splitting since most of the wood was from limbs and trunks no larger than 12". I was getting unheard of performance out of that wood and people would tell me, try some oak and hickory. I did and the locust performed better. Burned overnight and kept the house warm so that wake up was just add more wood and good for the day. It is fantastic firewood.
Don't bother clearing any of it unless you intend to keep it mowed two or three times a year. Other wise you will wind up with a thicket that is almost impassable within a few years. Unless you bulldoze it and root rake diligently, and plow it and cultivate it. Even then you will have locust sprouts in your crops.
It has been love hate about the locusts but for now I love one of my locust plots. I cleared a couple acres into rows that I bush hog (my grandson calls it canopy acres because of the neat rows of trees covering the sky) and every summer go out and take my pick of trees to fell and saw up into wood. With the loader and these neat rows of mowed space it is like taking candy from a baby to get fire wood, and the grapple enables me to clean up so fast the fun never got a chance to turn into work.
The patch is gaining still and I wonder just how many houses it would heat perpetually. Yup they are nasty but perhaps that sows ear can turn out to be a bit of silk purse with an adjustment of attitude.
These particular species of black locust do not have a lot of thorns and I had only occasional flat tire due to that and never a rear tire. Perhaps lucky.
