Abstract
Now, coniferous trees of the enormous quantity that it planted in the days after the war reaches time to cut it down. But, it can't be said that no prospect of effectively using coniferous trees has yet emerged. To use that effectively, improvement to the high-performance wood is indispensable. In this paper, we try to destroy closed border pit membrane of Sugi (Japanese name, its scientific name is Cryptomeria japonica D.Don) to improve the permeability of water. And dried Sugi infused with several medicine to have it become a fire-resistant wood. Using the suitable strength of underwater shock wave, it is possible to destroy only closed border pit membrane but affect the original strength.
