Considering the implications of species on pigment estimation from leaf spectroscopy

Foliar pigment concentrations have the potential to provide information regarding the physiological status of vegetation. Since foliar pigments cause wavelength specific absorption, these spectral regions and metrics derived there from, have been applied to estimate pigment concentrations. Some literature suggests that foliar attributes not related to chlorophyll concentrations influence the reflectance-pigment relationship. To investigate the appropriateness of these relationships across species with different pigment types and potentially different mesophyll cell structure, a dataset was collected throughout fall senescence. This dataset provided a wide range of pigment levels for five dissimilar tree species. Regression models were generated and compared. This data determined that the widely applied red edge position is sensitive to different tree species. Not only were different model coefficients found but occasionally different functions. The continuum removed and depth normalized left area appears to be a more robust alternative to REP for estimating chlorophyll.