Small-scale wood gasification combined heat and power plants, which are promising for the realisation of a decarbonised society and local revitalisation, have a low capacity-utilisation rate in Japan, partly due to the generation of solidified products (clinker) from the inorganic components of the wood fuel. The ash fusion characteristics of different parts of cedar wood (heartwood, sapwood and bark) have been elucidated and it is clear that the fusion temperature of heartwood ash is lower than that of sapwood and bark ash. In previous studies, additives have been investigated, but the high cost of additives has been a problem. Therefore, in this study, it was decided to determine the blend ratio that could increase the ash fusion temperature by blending different ratios of sapwood or bark to heartwood.