• Introduction of native tree species in sites invaded by Japanese Knotweed Taxa and a study of its affect of the seedbank.

      Toews, Hans-Peter C. (2013-01-15)
      The invasion of three closely related taxa of knotweeds: (Japanese knotweed) Polygonum cuspidatum, (giant knotweed) Polygonum sachalinensis, and their hybrid Polygonum x bohemica in riparian corridors throughout the eastern U.S. has a negative impact on native plant communities. In the study the following research objectives were addressed: 1) To determine if forms of mechanical control (cutting and tilling) could be used to allow tree saplings to become established in knotweed invaded sites. 2) To compare height and leaf number of saplings of four native tree species inside and outside of Japanese knotweed stands. 3) To compare the soil seed bank density and composition in knotweed invaded versus noninvaded sites. No significant differences were found in the growth or survival among the saplings of four native tree species across treatments. Although treatments did not significantly affect sapling growth trends showed that saplings in the tilled treatment had the greatest growth across treatments over the growing season. A longer running experiment is needed to establish any emerging patterns in the data. Significantly greater densities of seedlings were observed in non-invaded than invaded sites and significantly greater densities of native seedlings were observed in non-invaded than invaded sites. Knotweed invasion does significantly affect the seedbank.
    • Techniques to suppress invasive Oriental Bittersweet (Celastrus orbiculatus) on Presque Isle State Park in Erie, Pennsylvania.

      Wooten, Jessica (2013-07-10)
      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.