To explore the applicability of the carbon isotope composition (δ13C) of fossil charcoal for the quantitative reconstruction of paleoclimates, we selected five points in Shaanxi province, from north to south, to collect modern Pinus species and Quercus species to sample covering areas with obvious climatic differences. In order to reveal the relationships between δ13C of charcoal and climate variables on the basis of carbonization experiments, we evaluated the fractionation mechanism of δ13C of charcoal, and compared the differences between δ13C of charcoal in wildfire experiments and indoor experiments regarding genera and species. The results showed significant differences in δ13C between genera but no significant differences among species. Additionally, the δ13C of charcoal was significantly negatively correlated with precipitation and positively correlated with evaporation, which could be determined from δ13C values in the study area to reconstruct ancient precipitation and evaporation in the future.

The objective of this paper is to examine the representativeness of charcoal taxa at archeological sites in northern China. We carried out standardized laboratory compression tests on 168 samples representing 21 taxa charred at four different temperatures to characterize the mechanical properties of common taxa in temperate China. The results indicate that significant fragmentation differences occur between taxa. Ring-porous/semi-ring-porous taxa with a moderate density (>0.55 g/cm3) are overrepresented, while those with a very low to low density (<0.55 g/cm3) are moderately represented. Diffuse-porous taxa with slightly dense uniseriate rays, rare multiseriate rays and distinct helical thickenings are underrepresented, and those with slightly dense multiseriate rays are overrepresented, while those with rare to moderate multiseriate rays and helical thickening absence are moderately represented. Gymnosperm trees are generally well represented. Among the ubiquitous taxa at the archeological sites across northern China, Quercus and Ulmus may be overrepresented, and Pinus, Salix, Populus, and Acer may be underrepresented, while Betula may be moderately represented.