Would it be possible to plant trees on the moon to create oxygen?
Terra-forming is not easy really, first you have to create an atmosphere foremost, the trees would stand little ability to survive in space that is -220F and below and would freeze otherwise. Space as you know is a vacuum also, a vacuum is a place where no atmospheric pressure exists and no environmental aspect such as breathable oxygen or nitrogen can sustain life. Basically in short terms they would have to pump gases into the atmosphere around the moon and build it up so the gases can sustain life. The moon also would have to have a stable orbital rotation that would allow life to flourish, it even now does not have that capability whether they chose to do the terra forming or not, it travels far too wide a path from the Earth and Sun to make an inhabitable place to live or grow crops on.
