Techniques to suppress invasive Oriental Bittersweet (Celastrus orbiculatus) on Presque Isle State Park in Erie, Pennsylvania.

Abstract

Oriental bittersweet (Celastrus orbiculatus) is a deciduous, woody vine native to Southeast Asia. Currently this invasive is considered a major threat to native forests in the eastern United States. Some characteristics associated with its’ competitive ability include shade tolerance, ability to colonize a wide range of suitable environmental conditions, and prolific seed production, viability and germination. These factors contribute to difficulties related to the suppression and containment of this species. In order to preserve native plant communities at Presque Isle State Park in Erie, PA, a total of 5 treatments, each having 4 replicates was established to test various procedures to suppress this invasive species and restore native plant communities. Two control treatments involved either making cuts of all stems at chest height and ground level (window cut) with no subsequent treatment or no action at all. Additional treatments consisted of a basal stump herbicide application of a 100% solution of either triclopyr or glyphosate to every cut stem immediately after window cuts were made. The last treatment method consisted of making window cuts followed by a foliar herbicide application 5 weeks post cut with a backpack sprayer containing a solution of 6% glyphosate and 3% triclopyr. Data analysis show that the most effective method to suppress C. orbiculatus is by making a window cut of all stems followed by a foliar herbicide application 5 weeks post cut. Plots with this treatment had significantly fewer regrowth stems and these stems had a trend towards shorter length as opposed to other treatments. This knowledge has the potential to assist not only Presque Isle State Park but many other locations afflicted with the presence of this invasive species.