SPECTRAL DISCRIMINATION OF HARDWOOD TREE SPECIES AND STRESSED ASH TREES IN SUPPORT OF THE EMERALD ASH BORER EMERGENCY PROGRAM(Abstract)

摘要

Emergency programs such as Emerald Ash Borer could benefit greatly from vegetation mapping to locate susceptible trees within urban and forested environments and potentially locate damaged trees. Currently, detection surveys rely on visual identification of beetles and/or visible damage. These detection efforts are labor-intensive with surveyors first identifying tree species and then examining susceptible trees for signs of beetles. Remote sensing can be a useful tool for mapping vegetation and advances in sensor technology continually improve the information content of imagery. This paper investigates whether northern hardwood tree species can be differentiated from ash tree species using hyperspectral reflectance in the visible to shortwave infrared spectral range. Field sites were established in 2004 & 2005 within the area infested by Emerald Ash Borer. Spectral signatures for typical northern hardwood tree species within the area were collected along with both healthy and stressed ash trees. Data was collected using an ASD FieldSpec Pro full range spectrometer and included bands from the visible spectrum to short wave infra red. Data was primarily collected at the leaf level using an ASD plant probe, but when sky conditions were favorable, whole tree spectra were collected using a bucket truck to reach over the top of the canopy. Preliminary data from 2003 show good separability between individual tree species and ash trees as well as being able to detect levels of stress in ash. This work will also serve to validate airborne hyperspectral data being collected as part of a larger remote sensing research effort.