There is no clear signal of ester bonds from the FT-IR spectrum (1733 cm -1 ), which could be explained by the low concentration of the oligomeric species detected by 1 H NMR. However, it is possible to identify the presence of mid-chain unsaturation from the shoulder at 3003 cm -1 26 (as seen from 1 H and C NMR) as well as bands associated with aromatic species at 1516 and 1599 cm -1 29,32,33 , which may derive from the aromatic fraction of suberin. The brown color of the extractives further supports the hypothesis of lignin-like compounds even though no signal in the 1 H NMR can be assigned to such species. We hypothesize that such a fraction is removed by the filtration step before testing.