Morphological characteristics of Quercus variabilis charcoal prepared at different temperatures
- 260 Downloads
The morphology of charcoals was investigated by scanning electron microscopy. Charcoal of Quercus variabilis was prepared in an electric furnace under nitrogen gas atmosphere at 400, 600, 800 and 1,000°C. Charring temperature greatly affects the structure of charcoal. In charcoal prepared at 400°C, most of the morphological characteristics remained relatively unchanged with the exception of the cell-wall layering. The cell walls appeared homogenous and glass-like. Above 400°C, there was an increase in cell-wall thinning and volumetric shrinkage with an increase in the charring temperature. These two factors were responsible for most of the observed changes in structure. Fracture surfaces became increasingly rough and disrupted. Vessel elements were increasingly distorted and tyloses disintegrated with increases in temperature. Parenchyma cells exhibited greater shrinkage except at the pits. This resulted in the appearance of distinctive small protuberances over the surface of the parenchyma cells. Rhomboidal calcium crystals were found to be abundant at all the temperatures studied, but at 800 and 1,000°C the crystals had a sponge-like appearance.
KeywordsCharcoal Vessel Element Volumetric Shrinkage Small Protuberance Honeycombed Appearance
This work was supported by Kangwon National University Grant [3004113-1-1(2004494)].
- Angeles G (2001) New techniques for the anatomical study of charcoalified wood. IAWA J 22(3):245–254Google Scholar
- Blankenhorn PR, Jenkins GM, Kline DE (1972) Dynamic mechanical properties and microstructure of some carbonized hardwoods. Wood Fiber 4(3):212–224Google Scholar
- Blankenhorn PR, Barnes DP, Kline DE, Murphey WK (1978) Porosity and pore size distribution of black cherry carbonized in an inert atmosphere. J Wood Sci 11(1):23–29Google Scholar
- Beall FC, Blankenhorn PR, Moore GR (1974) Carbonized wood—physical properties and use as an SEM preparation. J Wood Sci 6(3):212–219Google Scholar
- Cutter BE, McGinnes EA Jr (1981) A note on density change patterns in charred wood. Wood Fiber 13(1):39–44Google Scholar
- Elder TJ, Murphey WK, Blankenhorn PR (1979) A note on the thermally induced changes of intervessel pits in black cherry (Prunus serotina EHRH.). Wood Fiber 11(3):179–183Google Scholar
- McGinnes EA Jr, Kandeel SA, Szopa PS (1971) Some structural changes observed in the transformation of wood into charcoal. Wood Fiber 3(2):77–83Google Scholar
- Prior J, Alvin KL (1983) Structural changes on charring woods of dichrostachys and salix from southern Africa. IAWA Bull 4(4):197–206Google Scholar
- Prior J, Alvin KL (1986) Structural changes on charring woods of dichrostachys and salix from southern Africa: the effect of moisture content. IAWA Bull 7(3):243–250Google Scholar
- Prior J, Gasson P (1993) Anatomical changes on charring six African hardwoods. IAWA J 14(1):77–86Google Scholar
- Slocum DH, McGinnes EA Jr, Beall FC (1978) Charcoal yield, shrinkage, and density changes during carbonization of oak and hickory woods. J Wood Sci 11(1):42–47Google Scholar