Charcoal from biomass residues of a Cryptomeria plantation and analysis of its carbon fixation benefit in Taiwan

Charcoal production as an age-old industry not only supplies fuel in developing countries, in recent decades, it has also become a means of supplying new multifunctional materials for environmental improvement and agricultural applications in developed countries. These include air dehumidification and deodorization, water purification, and soil improvement due to charcoal's excellent adsorption capacity. Paradoxically, charcoal production might also help curb greenhouse gas emissions. In this study, we made charcoal from discarded branches and tops of wood from a Cryptomeria plantation after thinning using a still-operational earthen kiln. Woody biomass was used as the carbonization fuel. The effect of carbonization on carbon fixation was calculated and its benefits evaluated. The results showed that the recovered fixed carbon reached 33.2%, i.e., one-third of the biomass residual carbon was conserved as charcoal which if left on the forest ground would decompose and turn into carbon dioxide, and based on a net profit of US$1.13 kg−1 for charcoal, an annual net profit of US$14,665 could be realized. Charcoaling thus appears to be a feasible alternative to promote reutilization of woody resides which would not only reduce greenhouse gas emissions, but also provide potential benefits to regional economies in developing countries.