Variation of quantitative anatomical features due to carbonization and their impact on size classes for charcoal identification

Abstract Species identification of carbonized wood holds significance for various scientific disciplines, including botany, palaeontology, and archaeology. Identification also contributes to the preservation of endangered wood species and forests, and supports climate research. With regard to the identification of wood and wood products, all international research institutions adhere to the IAWA list of microscopic features for hardwood and softwood identification, established by the IAWA Committee in 1989. Our comparative anatomical studies of 30 different species reveal significant dimensional losses of quantitative features during the charring process. Specifically, the findings indicate a shift in size classes, with varying percentages of loss in anatomical features from solid wood to charcoal for most of the taxa analyzed. Consequently, the size classes defined in databases for solid wood differentiation cannot be directly applied to charcoal identification. Furthermore, the present study employs statistical evaluations to illustrate the application of conventional size classes for the parameters: tangential diameter of vessel elements, intervessel pit diameter, ray height, and width. The implications of these findings for charcoal research are discussed in detail.