Fig. 4

Ratios between areas of FTIR absorption bands attributed to lignin and carbohydrates (1503/1730, 1503/897), and hemicellulose and cellulose (1730/897) obtained for the oak reference wood (ref) and for the wood samples after 2, 4, 6, 8 and 10 years of burial in a SP1 (wet peat) and b SP4 (water sediment)