You should make the cut using these three separate steps:
Step one: Undercut the branch at F, like shown in the diagram below. F is just a short distance away from the trunk, so be careful when trimming. By cutting at the F spot, you will prevent the weight of the branch from tearing along the bottom and damaging trunk tissues.
Step two: Cut the major portion of the branch at G. Se how close f and G are to one another, so it is important to be a precise as possible.
Step three: Make the last cut from A to B. This is the base of the branch tissue.
The swollen area where the branch and trunk meet is called the branch collar. It is easy to cause damage to the branch collar when cuts are not correctly, so please be careful. Cuts that cause damage to the branch collar will result in differing formations around the pruning wound. Images CE2, CB3 ad AE4 are examples of a collar that has been damaged. When properly done, a perfectly round doughnut of new wood tissue will form around the wound, as shown at the bottom of the picture marked with AB1. Examining the cut in the following seasons will show you how well you made the cut.