Naio
Naio is very common on Oahu and appears to be the dominant native tree near the coast, although you'll usually encounter it as a bush.
Background Information
Naio is indigenous to Hawaii. Its nickname is Bastard Sandalwood because during the sandalwood trade, they use to pass it off as sandalwood. In Ancient times, Hawaiians used the wood to make post, rafters, frames and beams. Today it is used in wood craft.
Naio
The tree can grow as high as 50 feet, although it is more of a bush or small tree especially on Oahu. The flower is usually white and may have a tinge of purple or yellow. The flower can be a good indicator of identifying the plant as not too many coastal plants have a flower that looks like Naio.
Alan Davis 2018
Kalaeloa Beach Park 2018