Fig. 2 Ratio of lignin-derived phenolic acids to aldehydes of the vanillyl (ac/al)V and syringyl structural units (ac/al)S as related to mean annual temperature (MAT, °C) for the fine sand fractions (20–250 µm)
Fig. 2 Ratio of lignin-derived phenolic acids to aldehydes of the vanillyl (ac/al)V and syringyl structural units (ac/al)S as related to mean annual temperature (MAT, °C) for the fine sand fractions (20–250 µm)