NIR and SWIR Reflectance Characteristics of Dry Plant Materials of some 'Eucalyptus' species

Abstract

Spectral reflectance measurements of dry plant materials of several species of eucalypts were recorded using field based PIMA spectroradiometer and analysed for differences in reflectance in the shortwave-infrared (1000-2500nm) region. Absorption features due to different chemicals and compounds were also identified. Results indicate that dry plant materials have reflectance spectra completely different from that of green leaves. Absorption features which were masked by chlorophyll and water in green leaves were much clearly visible in reflectance spectra of leaf litter and barks. The presence of unique spectral features in dry plant material suggests that there is a strong possibility of developing vegetation indices based on these new positions. This reflectance information would also be useful in modelling canopy reflectance as dry plant material forms part of the canopy and so contributes to the reflectance spectra. The quantity and exposure of dry plant material varies both spatially and seasonally, and so can also be used for water stress and fire fuel monitoring.