Black Locust Trees Burn Me!

Black locust grove in the back yard.

       Black locust is a fast-growing tree, attaining a height of seventy feet or more with a diameter that can exceed a yard. Nothing excels black locust for longevity when used in contact with the ground.  Posts have been known to last a hundred years. It makes excellent firewood when cured, and will even burn when wet. When my husband's family ran out of firewood during the winter, they could cut down a black locust tree and use the wood immediately. The tree fixes nitrogen in the soil, and bees use the flowers to make a famous honey. Its leaves are so small that it's rarely necessary to rake them in the fall; the wind disperses them. Sounds like a perfect tree to grow in your yard. 

Black locust at the edge of a garden,
growing from a root runner.

                                        
        It's not. The young trees and new growth sport thorns.  Large limbs on older trees have a deserved reputation for becoming widow makers. The tree spreads by seed and roots. This makes it invasive. A newly cut stump will produce dozens of sprouts. While you're trimming back the new growth, new trees will be coming up dozens of yards away. Want to clear ground for a garden? If you have black locusts in the area, you may run into a latticework of roots that will have to be dug, chopped, pulled, burned. Whatever it takes to get them out, and you won't get them all. 
       I've tried all sorts of tricks to get rid of specific trees.  To control the black locust invasion in the barnyard, I'm using a strong herbicide.

The tall growth around the silo is black locust trees.
The barnyard is choked with younger trees in a broad line
from the silo all the way to the left side of this photo.

There's no way I could begin to control them with my usual shovel work.  Even bulldozing wouldn't stop them.  Actually, bulldozing is what brought about the mess in the photo on the right. The machine tore out the bigger trees, but new growth sprouted from every little piece of root left in the ground.
         My most successful ploy for getting rid of a single tree has been to cut it down and cover the stump with heavy black plastic (the leftover pool liner I've mentioned in other blogs).  It's unsightly and must be left in place for months, and I still need to cut away anything the grows outside the covered area, but the stump does actually die, eventually.
       Oddly, as invasive as the tree is, it hasn't spread onto neighboring property. We have our own little copse around our old farmhouse. What I suppose is the mother of them all stands in the front yard, with a trunk easily three feet in diameter.  Black locust isn't native to this area, but that tree was big when my husband's family moved here over sixty years ago. I think of it as part of the history of this old house.  Bees have a hive in another black locust tree down by the road in front. Last year I observed bees there getting ready to move, a swarm five feet wide with a solid, living basketball-sized mass in the center. Awesome. As much trouble as the species is, we haven't made an effort to get rid of it completely. It's too useful for posts and as firewood.  I have to admit that the yard would look naked without it.
       Since the original post, I've learned a few more things about black locust, including an additional way to get rid of it--bring in the goats. We haven't done this yet, but maybe, hopefully, someday.... And of course, now that I may have a workable way of erradicating new growth, I've found another use for it. Slim, long, flexible black locust twigs make outstanding withies for wattling. I'm imagining really cheap-to-make fences for privacy and less ambitious ones for keeping the dogs out of certain areas. I want to make tomato towers using them. Then I've seen black locust listed as a source of poultry forage. Gaia's Garden says the seed pods can be ground and fed to chickens. Live and learn! (Isn't it fun!)