Quantifying Chlorophylls and Caroteniods at Leaf and Canopy Scales: An Evaluation of Some Hyperspectral Approaches

An investigation was undertaken into the effectiveness of a range of hyperspectral approaches for estimating the concentrations of chlorophyll a, chlorophyll b, and the carotenoids at the plant canopy and leaf scales. Measurements of spectral reflectance, biophysical characteristics and pigment composition were made for a bracken (Pteridium aquilinum) canopy, and its components, throughout a growing season. The results indicate that narrow-band reflectance indices, such as the pigment-specific simple ratio (PSSR), can be developed which have extremely strong relationships with the concentration per unit area of individual pigments at the canopy scale. Spectral derivative approaches, particularly those based on pseudo absorbance (Log 1/R), are also closely related to canopy pigment concentration per unit area, but are more useful for deriving estimates of the concentration per unit mass of photosynthetic pigments at both canopy and leaf scales.