3. Results and Discussions
3.1. Method of making specimens
The damages of surface of sapwood and heartwood are shown in Figure 4 and 5, respectively. The
fungal attacked surface was softened and cracked in both specimens, sapwood and heartwood. In all
specimens, the fungal attacked area corresponded to the wrapped area, and both end surfaces of specimen
were kept sound condition. Our decay method has enabled the decayed specimen to fix firmly on the
apparatus and carry out the nail shear test. The cracks and softening in sapwood was severer than in
heartwood, thus it was verified that heartwood was more durable than sapwood.