PARENT SESSION
Poster Session: Linking Science, Policy, and Management
Thursday, November 6, 2003, 5:00 PM to 7:00 PM
Global Ballroom
Hedera helix: effectiveness of removal protocol adapted to field research data.
Diedrich, Sandra1, Broshot, Nancy2, 1 Ivy Removal Project, Portland Parks and Recreation, Portland, OR, USA2 Linfield College, Portland, OR, USA
ABSTRACT- In 1994 the Ivy Removal Project was organized to develop control strategies for invasive Hedera helix in Forest Park, a 5400 acre urban forest preserve within Portland, Oregon. Initial methods for removing ivy from trees involved cutting the vines around the lower portion of the trunk and stripping them away, then pulling ground ivy within a three foot radius around the tree. A field research study undertaken by Nancy Broshot and Amanda Durkee into the growth patterns of Hedera helix found that ivy growing within 1.8 meters of a tree was significantly more likely to grow towards the tree than in a random direction or away from the tree (p=0.006). Exiting protocol was adapted to these findings by increasing the ground removal zone to a six foot radius around the base of the tree. Because many of our workers are unaccustomed to the metric system, feet were used to clarify the distance. The removal protocol was given the moniker "lifesaver" to create a strong visual image of the tree bole being at the center of the six foot ivy free ring. This new protocol was first used in the summer of 1996 with annual monitoring conducted where the modified protocol was employed. Many trees given a "lifesaver" in 1996 and subsequent years still did not have ivy regrowing up the trunk in the summer of 2002. The extent to which the tree remains free from regrowth up its trunk appears to depend on the quality of the removal work performed on the ground cover ivy and the extent to which the roots are thoroughly removed within the six foot radius. Additional field studies are being conducted to determine the effectiveness of this intervention and to ascertain how long regrowth up the trunk is inhibited by this control strategy protocol.
Key words: removal protocol, Hedera helix, application of research to control strategy, adaptive management