Buckthorn in our Forests
This week I’d like to talk about an invasive species that can be easily seen in the fall. Buckthorn is an invasive plant that most commonly looks like a shrub, but once mature can form into a small tree. There are two main varieties of buckthorn that are of concern in Wisconsin: common buckthorn (Rhamnus cathartica) and glossy buckthorn (Frangula alnus). In general, common buckthorn likes to invade forest understories and other upland settings, while glossy buckthorn tends to invade wetter settings which may include lowland and some wetland habitats. Both common and glossy buckthorn can reach heights of 10 to 25 feet and create a dense canopy that allows for little to no forest undergrowth. Besides limiting forest undergrowth, these plants also provide very little value to wildlife. The berries from buckthorn appear to be enjoyed by birds; however, they actually act as a laxative, which causes the seeds to spread easily. These berries also release a toxin into the soil that limits other plant growth.
As I said earlier, Fall is a great time to assess if you have buckthorn on your property. Buckthorn stays green and holds on to its leaves late into the fall, when most other plants have already dropped their foliage. This unique characteristic of buckthorn makes it very easy to locate and confirm they are buckthorn before treatment. Buckthorn is recognized by its dark green round leaves and black berries, and occasional thorns. Young buckthorn sprouts can be hand-pulled, and treatment of older buckthorn can include a variety of methods, including mechanical and herbicidal. By removing buckthorn on our properties, we are all contributing to a healthier, more diverse and more enjoyable forest landscape. Last week, I spent part of the day with Forest County’s Assistant Forest Administrator, Jared Oemig, pulling and treating buckthorn on Forest County land. It helps to treat this species before a logging job occurs, so it doesn’t get access to more sunlight and spread rapidly.
