ABSTRACTDENDROCHRONOLOGY AND NEAR-INFRARED SPECTROSCOPY (NIR) OF WHITE ASH INFESTED BY EMERALD ASH BORER IN MICHIGANByKaelyn Anne FinleyEmerald ash borer (EAB) (Agrilus planipennis Fairmaire), is a non-native beetle responsible for widespread mortality of several North American ash species (Fraxinus sp.). Current non-destructive methods for early detection of EAB in specific trees are limited, which restricts the effectiveness of management efforts. This study explored the potential of dendrochronology and near-infrared spectroscopy (NIR) as novel methods for detection of EAB on white ash (Fraxinus americana) in Michigan using a handheld increment borer. Increment borers are used to non-destructively and efficiently collect increment cores from trees. While the potential of dendrochronology for early detection of EAB in Michigan was inconclusive based on the results of this study, white ash in Michigan was shown to have a strong negative relationship with precipitation and available moisture in the summer of the previous year. Increased risk of branch failure due to EAB infestation may further increase ash susceptibility to wind damage. Near-infrared spectroscopy was successfully used to discriminate between bark, phloem and xylem tissues from EAB infested and visually healthy trees using linear discriminant analysis. The xylem spectra transformed using a Savitzky-Golay, 1st derivative smoothing filter over the full NIR wavelength range observed in this study (1134-2190 nm) had the highest discriminating power at 97% correct classification accuracy.
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