Acacia Koa

This young tree shows something we were not seeing on the mature trees. The large plant parts in the center of the image which look like leaves are actually this tree's modified stems. The leaves are the smaller opposite leaves on the left hand side of the image which look like acacia or some sort of legume leaves. Both parts are photosynthetic, but the greenery you see when you look into a Koa forest is mostly stems, not leaves. This is the kind of thing we silly biologists find fascinating.