Maybe worth remembering that "trees" have evolved many times on earth. i.e. trees do not all share a common tree-like ancestor. The woody-trunk-and-branches pat

Maybe worth remembering that "trees" have evolved many times on earth. i.e. trees do not all share a common tree-like ancestor. The woody-trunk-and-branches pattern was just useful enough that it evolved many times. Which makes me suspect that aliens would likely have something tree-like on their home world, and would have also learned to build using it.