“…As mentioned before, C=O 239 stretching in lignin and carbohydrates seems relevant for the classification. The 240 greater contributor to the discrimination between subclass groups was the 241 wavenumber 1769, attributed in the literature to C=O stretching in acetyl groups 242 of hemicelluloses (xylan/glucomannan) Bjarnestad and 243 Dahlman, 2002;244 Mohebby, 2008244 Mohebby, , 2005Rana et al, 2009;Stewart et al, 1995), this contributor 245 was followed in order of importance (the second greatest F-value) by 1697 246 assigned to C=O stretching (Coates, 2000;Silverstein et al, 2005), 3613 and 3610 247 (O-H stretching (Coates, 2000)), and lastly 1701 related to Conj-CO-Conj lignin 248 Larkin, 2011). 249 STEPDISC method was run over different split datasets from ring dataset, the 250 imbalance effect on the results was also checked; in such a way, the discriminator 251 wavenumbers from the output of STEPDISC method were selected and used to 252 construct linear regression models.…”