The second one is acoustic koa.

第二是acoustic koa。

Hawaiian men and women of all ages and social classes participated, riding surfboards shaped from koa, breadfruit, or wiliwili trees.

夏威夷龄段和社会阶层的男女都参加了比赛，他们骑着由相思木、包果树或威利威利树制成的冲浪板。

Boatmaking was so revered that there were specific religious rituals throughout the entire process of building one, starting with selecting the correct koa tree.

造船业是如尊敬， 以至于在造船的整过程中都有特定的宗教仪式，从选择正确的相思树开始。