1) What are the important spectral characteristics of vegetation that I should know about?
A: The cells in plant leaves are very effective scatterers of light because of the high contrast in the index of refraction between the water-rich cell contents and the intercellular air spaces.
Vegetation is very dark in the visible (400-700 nm) because of the high absorption of pigments which occur in leaves (chlorophyll, protochlorophyll, xanthophyll, etc.). There is a slight increase in
reflectivity around 550 nm (visible green) because the pigments are least absorptive there. In the spectral range 700-1300 nm plants are very bright because this is a spectral no-man's land between the
electronic transitions which provide absorption in the visible and molecular vibrations which absorb in longer wavelengths. There is no strong absorption in this spectral range, but the plant scatters strongly as mentioned above................