Hi we have a navel orange tree that's probably over 100 years old, so not new. It produces an amazing amount of sweet oranges, so we don't want to mess that up, but it's growing closer and closer to the ground (it's sort of a canopy shape), and we'd like to continue to enjoy the shade without bonking our heads! I just want it up from the ground a bit...is it okay to trim a bit? Is this time of year okay? We're in southern California, so we don't really have frost (lows of 50s in winter, low 90s in summer).

Thanks!