Impact of carbonization parameters on anatomic aspects and near-infrared spectra of three species from Mozambique

Abstract

This study characterizes charcoal from Androstachys johnsonii (Picrodendraceae), Bobgunnia madagascariensis (Fabaceae) and Sterculia quinqueloba (Malvaceae), made by different carbonization processes, based on wood anatomy and NIR spectroscopy to verify the impact of the parameters and contribute to a database for charcoal identification and control. In the three species analyzed, changes in anatomical characteristics after carbonization were different and formed groups regarding charcoal programs as a result of anatomical and chemical characteristics. In vessel and ray dimensions and frequency, no linear relation to total time or final carbonization temperature was observed, although there were some interactions between species and program conditions. In the near-infrared spectra, the region from 4000 to 5000 cm−1 showed more distinction between the charcoal programs. There was a separation of samples carbonized with lower intensity (400 °C and 40 min), denoting minor chemical degradation of species, from samples submitted to other programs with a final temperature of 450 °C and total time between 2 and 6 h. Near-infrared spectroscopy showed potential to discriminate species in different carbonization processes. Final temperature had a stronger influence on species distinction than the total processing time.