Restoring forest cover and enhancing biodiversity of the Carolinian forest in Ontario affected by Ash tree decline from the Emerald Ash Borer

Abstract

The Emerald Ash Borer (EAB) is an invasive insect killing millions of ash trees in North America, threatening functional extirpation of ash (Fraxinus) species from the continent. Deemed the costliest biological invasion by a forest insect in history, EAB has cost an estimated 12.5 billion USD to the United States through 2020. The EAB has also caused tremendous economic loss in Canada, particularly in the Carolinian zone of Ontario, an area inhabited by all five species of ash native to Canada which were once major forest species. This Major Research Project will lay out a proposal for the underplanting of native, preferentially uncommon, tree species in forests impacted by ash tree decline from the EAB. Uncommon species can be defined as provincially endangered or rare and/or locally rare or absent. Uncommon species are preferred as they may increase a forests resistance and resilience to disturbance, as described by the diversity-stability hypothesis. Motivated by a need for more in-situ management options in response to EAB, the proposed activity, including work to date, could be used to help restore forests affected from ash decline and increase the resistance and resilience of Carolinian forests to future disturbance.