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Dr. Jordan M. Marshall
Department of Biology
Indiana University – Purdue University Fort Wayne
Emerald ash borer (Agrilus planipennis [EAB]) is an invasive species introduced from Asia to North America in the 1990s. Since introduction, EAB infestation has been reported in more than 20 US states and 2 Canadian provinces causing significant mortality in ash (Fraxinus spp.). However, some ash trees appear able to survive EAB attack, even within a few miles of the de facto epicenter in southeastern Michigan. Ash trees were selected from a gradient of apparent host tolerance to EAB attack in Kensington, Oakwoods, Lower Huron, and Willow Metroparks, Michigan. Cores from 80 trees were collected using an increment borer during July 2013 and measured to determine the growth rates of the trees prior to and after EAB introduction. In a 6-year ordination analysis, there was substantial overlap of the growth rates of trees from all sampled parks. This growth rate overlap also extended throughout the three identified tolerance groups. A hierarchical cluster analysis including all years of growth also identified substantial overlap between the three tolerance groups, supporting the inference that growth patterns were similar throughout the life of the trees. Therefore, it does not appear that growth rates strongly influence mortality of trees in the event of an EAB attack. As the infestation of EAB in North America spreads, it becomes more important to identify the factors that increase the chances of ash survival. Results from this study will be incorporated into decision models to improve management of ash resources.
Biology | Life Sciences
Boyes, Kayla N., "Dendrochronological Assessment of Ash Growth Rates Relative to Emerald Ash Borer Infestation" (2014). 2014 IPFW Student Research and Creative Endeavor Symposium. 68.