Preliminary assessment of airborne imaging spectrometer and airborne thematic mapper data acquired for forest decline areas in the Federal Republic of Germany

This study evaluated the utility of data collected by the high-spectral resolution Airborne Imaging Spectrometer (AIS-2, tree mode, spectral range 0.8-2.2 μm) and the broad-band Daedalus Airborne Thematic Mapper (ATM, spectral range 0.42-13.0 μm) in assessing forest decline damage at a predominantly Scotch pine forest in the Federal Republic of Germany. Analysis of spectral radiance values from the ATM and raw digital number (DN) values from AIS-2 showed that higher reflectance in the near infrared was characteristic of high damage (heavy chlorosis, limited needle loss) in Scotch pine canopies. A classification image of a portion of the AIS-2 flight line, generated using log residual data in conjunction with the SPAM "Find" algorithm, agreed very well with a damage assessment map produced by standard aerial photointerpretation techniques. Results suggest that fine feature spectral differences in canopy reflectance have been detected in the near and short wave infrared by the AIS-2 and these features correspond with visual evidence of damage. The exact nature of these spectral fine features is not presently understood. These preliminary results indicate that both visible as well as near and short wave infrared reflectance features do characterize increasing damage in Scotch pine.