figure shows that the fitting parameters of each band are globally
grouped altogether. The most important parameter is therefore
more the presence of a decomposition band than its profile. It is
thus necessary to add a spectral decomposition step, which goes
deeper in the morphological analysis of the CH stretching region,
in order to obtain a good clustering depending on the chemical
families and/or geographical origin of the tree species. Working on
the morphology of the CH spectral region can be sufficiently
informative if the treatment procedure is well defined. Indeed,
choosing the correct number and position of bands for the spectral
decomposition is a critical point to get a relevant description of the
spectra morphology.