I like the idea, but I think we should all make the trees in the repository. We have a community, why not use it? And it's much more satisfying to know that what you're using is from "local farms" than from some unknown location. :D
Also, I don't think we should do this for planes and cars, because we may end up with these kinds of things copied and pasted everywhere with no real uniqueness. I think it's a much different thing for small vehicles and buildings than it is for trees.
I also do not think there should be any player submission limit. If a player has a custom tree they like at any point, they should be able to submit it for the community.
Fuck your useless nostalgia fest lol