Like Death Valley National Park, which is where A New Hope and Return of the Jedi shot some of its Tatooine scenes, Joshua Tree National Park is a desert environment.
According to a production listing for the Obi-Wan Kenobi movie that was uncovered by Omega Underground, the project’s working title is Joshua Tree.
However, as the report also noted, Joshua Tree could be referring to the Joshua Tree National Park, which is in southeast California.
At first glance, that may not seem at all important, and there are certainly cases where a major movie’s working title doesn’t correlate at all to the actual title or anything plot-related.