Writing a journal post is a great idea, but there’s no need to rush (new ideas and/or different perspectives may emerge in the coming days/weeks).
Open question: what about an umbrella project for merging the project “Trees That Need IDs” with existing bigger or more specific “tree” projects (like the ones for Southern Africa)? This umbrella project could be the preferred entry point for identifiers, while the project “Trees That Need IDs” could be the default entry point for observers (for observations not matching a more specific “tree” project). Publicizing (by you or, later, by others) the umbrella project would make known all the projects it contains (including your traditional project).