Three single wood plates, formalinized in the above manner, are bonded in piles with straight-grains crossing perpendicular to each other.Agents, other than formaldehyde by which etherification is performed in this embodiment, such as alkyl halide, aromatic halogenide, and vinyl cyanide, may be used to esterify the wood plates.The specific gravity of the single cross-grain Zelkova plate in this em