Effects of flood duration on seedling survival and growth of potential replacement species in black ash (Fraxinus nigra Marshall) forests threatened by emerald ash borer

Abstract

Within black ash (Fraxinus nigra Marshall) wetlands, black ash acts as a foundational species, resulting in high vulnerability to the invasive emerald ash borer (EAB) (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae). One mitigation strategy being considered is the planting of alternative tree species to increase compositional diversity, however, there is limited understanding of how replacement tree species tolerate flooding. A greenhouse experiment was used to explore early survival and growth of eighteen tree species in response to five flooding durations (3, 6, 9, 12, or 15 weeks). Seedlings were assigned to flood tolerance groups according to their responses to the various flooding duration treatments. Taxodium distichum (L.) Rich., Ulmus americana L., and Betula nigra L. were able to survive and grow with flooding durations of up to 15 weeks. Thuja occidentalis L., Acer rubrum L., Larix laricina (Du Roi) K. Koch, Quercus bicolor Willd., and Betula alleghaniensis Britton had high survival and growth rates with flooding durations up to 6 weeks in length. Finally, Juglans nigra L. and Acer saccharum Marshall responded poorly to flooding of any duration. These results can assist managers in matching potential black ash replacement species to the hydrology of their local black ash wetlands.

Keywords

• Great lakes region
• Invasive species
• Adaptive management
• Flooding
• Flood tolerance