Cutting off hair in ancient Asia (Japan, china, Korea & possibly some other Asian cultures) symbolizes being banished or rejected from their home. In the more modern age that is now, cutting long hair into a short cut means to forget the past, leaving the old and starting anew.
Actually pretty easy. Trees don’t reject tissue from other trees in the same family. You bend the tree to another tree when it is a sapling, scrape off the bark on both trees where they touch, add some damp sphagnum moss around them to keep everything slightly moist and bind them together. Then wait a few years- The trees will have grown together.
You can use a similar technique to graft a lemon branch or a lime branch or even both- onto an orange tree and have one tree that has all three fruits.