Woody vines - Porcelainberry/Bittersweet A. brevipedunculata/C. orbiculatus

- Bittersweet can grow up and over canopy trees, causing light deprivation and bark girdling, eventually causing collapse with heavy weight. It also makes trees more susceptible to wind and ice damage (VA DCR, 1999; Ellsworth, 2003; NH DOA, 2005). Both of these impacts may lead to loss of canopy and changes in views.

- Both porcelainberry and bittersweet can grow over and smother native ground vegetation (such as forbs and herbs), forming thick, almost monospecific stands (VA DCR, 1999; USDA, 2006).
    - Due to its high reproductive rate, long range dispersal, and rapid growth rate, bittersweet is also thought to be part of the reason behind the decline in the native species American bittersweet (C. scandens) (www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/invbio_plan_report_home.html; www.invasive.org/weedus/).

- Negative correlations have been found between tree seedling density and cover of porcelainberry. Also, cover of trees > or = to 5 cm dbh had negative correlation with cover of procelainberry (Yost et al., 1991), indicating that porcelain berry growth may lead to loss of canopy forming trees, community structure, or species richness.

- Kudzu and English ivy (P. montana) will blanket all vegetation layers as they grow, leading to loss of canopy trees, community structure, and native species (www.nps.gov/plants/alien/pubs/midatlantic/toc.htm).

- Following disturbance invasive vines have been shown to negatively affect the regeneration of other native plants including pre-established juveniles and resprouts from damaged adults (Horvitz et al., 1998).