Harry Hill just posted a link to this article on the Native Plant Society of BC email list: http://seattlepi.nwsource.com/specials/urbanforests/
Technical note: Predominant pest ivy here actually Irish ivy (Hedera hibernica), sold and planted as English ivy (H. helix). (Various H. helix forms also pestiferous here, but are not the more familiar, conspicuous, draping, smothering ivy of urban hillsides).