Non-chemical European buckthorn (Rhamnus cathartica) removal effectiveness and costs compared to chemical removal methods

Abstract

Common or European buckthorn (Rhamnus cathartica) and glossy buckthorn (Frangula alnus) are invasive species that can take over forest floors, alter soil properties, and out-compete native species for sunlight, nutrients, and water. Buckthorn is capable of assisting the cultivation of potential invasion meltdowns across the midwestern U.S. and southern Canada via increasing decomposition of ground litter, altering the carbon-nitrogen ratio in soils by increasing the nitrogen level, facilitating other species’ invasions, and shading out seedlings of keystone species. Buckthorn resprouts readily from roots and stumps, requiring laborious mechanical removal or potentially costly chemical treatment. A thorough review of the process, costs, effectiveness, and environmental impact that are associated with the removal of buckthorn has reinforced the need for finding a non-chemical control method that is similar in its ability to kill an individual buckthorn to its chemical counterparts. I investigated the cost and effectiveness of buckthorn removal using Buckthorn Baggies applied to cut stumps at two locations in Wisconsin. Buckthorn Baggies successfully killed 80.7% of buckthorn over the treatment period (95% CI: 70.8-87.8%), and effectiveness decreased with increasing stem width (z = 3.26, p = 0.001). Costs for Buckthorn Baggies average slightly higher than chemical removal methods. Buckthorn Baggies provide an environmentally safe way to remove buckthorn effectively. Success is dependent on stem width but may be dependent on other factors. Future research on Buckthorn Baggie effectiveness will need to be directed towards additional factors that may influence success rates.