The 'Ōhi'a 'ai tree is also called the Mountain Apple due to the fact that the reddish fruit of the 'Ōhi'a 'ai tastes (and looks to a degree) like apples. While it shares it's name with the 'Ōhi'a Lehua it is actually not related at all and instead is a member of the myrtle family. The common 'Ōhi'a name almost certainly resulted from the similarity in the flowers between the two trees.
The 'Ōhi'a 'ai was brought to Hawai'i by the original Polynesian voyagers in their canoes. The Hawaiians found the wood to be useful for building material and the fruit to be nourishing. Dyes were extracted from the 'Ōhi'a 'ai and used in making designs in tapa cloth.
The fruit of the 'Ōhi'a 'ai ranges from a very light pale pink to a deep red. One single fruit may exhibit a range of pink to red colors. The skin is thin and edible with several larger seeds near the center (which should not be eaten). The inside flesh of the fruit is white and very crisp - much like an apple. The taste ranges from being a bit similar to an apple or pear and is usually extremely juicy. The fruit can be eaten raw or dried or even pickled. However, people sensitive to niacin (flushing) may find themselves sensitive to the fruit (a friend of mine immediately broke out in hives upon eating a single fruit - though I have never experienced such an effect).
The fruit grows not from the end of the branches as with apples, but can appear just about anywhere on the tree including right out of the trunk. Unlike the 'Ōhi'a Lehua, when the flowers of the 'Ōhi'a 'ai fall they split apart into individual pieces and carpet the ground with a beautiful red layer.
The 'Ōhi'a 'ai In Ancient Hawaiian Medicine
Both the bark was used in various medicinal preparations including birthing as well as for cuts.