Do green olives and black olives come from different trees, or are green olives just picked when less ripe?

I think the sort of Pimento found in olives is actually a sweet spanish pepper. I’m not entirely sure, though. There are other things called “pimento”, like some sort of berry from an Allspice plant, and then there’s the band, Project Pimento….. but yeah. I’m thinking sweet spanish pepper.

Most olives we call black are usually a dark purple, the black canned olives have usually been treated with chemicals such as sulfates turning them black artificially.