Midewin National Tallgrass Prairie
  • Home
  • Trailheads
  • Downloads
  • Privacy Policy
  • Return to Portal
  • 4 Friend, Foe, Or Fencepost

    Leaf of the black locust tree.

    The woodland surrounding you consists of black locust trees. Planting of black locust trees was encouraged in the upper Midwest in the early 1900’s to prevent soil erosion. By 1930, the Farm Bureau bulletin #1628 was giving farmers detailed instructions on planting and growing black locust trees. Farmers had great concerns, in this Dust Bowl era of 1930, about losing their soil to the wind.  Black locust trees were recommended as one possible solution to soil erosion. They have an extensive root system that spreads with shallow rhizomes to form groves of trees that keep soil in place. The farmer that planted the original black locust trees here was following recommendations from the Soil Conservation Service.

    Black locust trees are fast growing medium sized trees. They can reach 25 feet by the end of their second year and top out at around 80 feet in height. The wood of these trees is very dense and slow to rot. This denseness results in a slow burning wood, a great wood choice for keeping a farmhouse warm in the cold months. The strength and durability in and out of soil also make black locust trees a good choice for very strong fence posts, stakes, and poles. Thus, it was a valuable tree to a farmer in the 1900’s.

    The leaves of this tree are distinctive, possessing a light and airy feeling. The leaves are 12 inches long with 7 to 21 oval leaflets that grow opposite one another. At night the leaflets fold up and droop. In the spring, beautiful trailing white flowers similar in appearance to wisteria give off a fragrant scent. This enticing scent attracts bees and other insects to sample its nectar. As a member of the legume family, black locust is known for its ability to fix nitrogen in the soil and improve soil fertility. It is the tree that is commonly used to restore soil in areas that have been mined.

    The native range for black locust tree is the southern Appalachian and the Ozark Mountains plus two small pockets of trees located in southeastern Indiana and southern Illinois. These trees prefer a humid climate with sandy or rocky soil. Black locust are a sturdy beautiful tree but they are aggressive and can become invasive. In Illinois, black locust trees pose a potential threat to upland natural areas and are a particularly serious management problem on hill prairies, sand prairies, and savannas. Today the black locust is present and has naturalized in all of the lower 48 states. Not many of the seeds from black locust germinate, but it is a clonal colony grower. This means that it sprouts new trees from its network of roots that hold the soil in place.

    There is a long history to this tree and the utilitarian purposes it served. It has been sought after for its durability in the ground as fence posts. Black locusts were brought to Europe and became a favorite ornamental landscape tree because of its delicate foliage and fragrant blooms. Stands of trees have been planted for honey production. The roots of these trees stabilized eroding areas and fixed nitrogen in the soil. England used the pollution tolerant root stabilizing black locusts to shore up the rail line embankments. Black locust has the highest beam strength of any North American tree. This strength made it a favored choice by Native Americans for making archery bows. It was also used as trunnels or large wooden pins that held timbers of wooden sailing ships together. For warmth, this slow burning black locust wood was a great choice. One cord of black locust wood, 4 ft. wide by 4 ft. tall by 8 ft. long, provided the same Btu potential as a ton of anthracite coal.  This is one of the highest Btu ratings of all American trees.

    Poisoning of domestic livestock, sheep, cattle, and horses has occurred from consumption of black locust. Although in Pakistan and New Zealand they grow this same tree to feed domestic goats. It is a food source for wildlife including white-tailed deer, rabbits, ruffed grouse, squirrels, and bob whites, as well as millipedes and the silver-spotted skipper butterfly. Black locusts provide important cover for nesting, roosting, and thermal protection of wildlife. While humans can be poisoned by eating the leafy or woody parts of the tree, they can drink tea made from the flowers and eat honey from its blossoms

    At some point a farmer planted black locust here because it was recommended as a way to protect his soil and serve farming needs in many other ways. There are positive and negative aspects to how black locust trees impact the environment. Once black locust are established they prove to be a hard species to remove. The shade provided by these black locust trees does make a nice place to contemplate these issues. 

    Read More