The aim of this research was to investigate the use of high spectral resolution sensors to recover more detailed information on the biochemical composition of forest canopies. The research was divided into two broad areas: laboratory and field studies. The laboratory studies were undertaken to determine the relationships between reflected radiation and the biochemical concentrations of foliage. A number of sample sets of slash pine, Sitka spruce, lodgepole pine and Japanese larch were analysed for their chlorophyll, water, nitrogen, lignin, cellulose, sugar and starch concentrations. Reflectance measurements were made for whole green, wet needles and dried whole needles. Stepwise regression analyses showed strong relationships between reflectance spectra and chlorophyll concentration. Wavelengths in the region of the red edge often had the strongest correlation with chlorophyll concentration. For the remaining biochemicals the relationships between concentration and reflectance were weaker. Also, for these biochemicals absorption features with the larget correlation with reflectance values could not be readily related to the wavelengths of absorption features determined from other work using near infrared spectroscopy techniques on dry ground samples. Field studies at two sites used similar statistical techniques to relate reflectance spectra (measured for canopies using the AVIRIS) to the biochemical concentration and content of the foliage. Except for chlorophyll and nitrogen the results of both the concentration and content data showed a weak comparison with laboratory results. Difference spectra between control plot canopy samples and fertilized plot canopy samples revealed a large number of apparent absorption features which could be related to the known absorption features of foliar biochemicals.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637829 |
| Date | January 1994 |
| Creators | Kupiec, J. A. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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