This bonsai technique allows you to select a branch that looks like a tree and root it while it is still attached and being nourished by the parent tree.
In the spring, select the desired branch. With a knife, cut one-third of the way into the branch, just below a lead node. Nature will want to start healing this would as soon as the cut edges meet, so keep them separated by inserting a toothpick. Dust the cut area with rooting hormone containing a fungicide, then wrap it with damp,sphagnum peat moss.
Next, wrap the moss with plastic, and close the top and bottom with twist-ties. When the plastic has filled with roots, cut the branch off just below the root system. Remove the plastic and moss and then pot the rooted branch.
The same bonsai cutting process can be used with a branch that reaches the ground. Make the cut on the bottom of the branch, insert a toothpick to keep the cut open, gently place the cut area in a hole in the ground, and cover it with soil. Roots should develop. If necessary, place a rock on the branch to keep it in place. Cut the branch from the parent and pot it when it has rooted.