We need trees. And not just for the oxygen they produce. We need to walk between them on cool moonlit nights and sit in their shade on hot sunny days. We need flowers and bushes and grass. We need plants and places to enjoy them to remind us that we are alive. Gardens. Parks. That’s why all of our space stations have them. And the mobile cities too. The city and station cores almost always have some form of park or garden that people can walk through and just get in touch with the nature that humanity grew up with. And countless public corridors have bushes or flowerbeds designed to liven things up as well. We need plants to live, and we have brought them with us everywhere we go.