Pruning orange trees what is meant by cutting out the collar of the branch
Pruning Orange Trees
Certified GKH Gardening Expert
You actually want to avoid this. The collar is a lump that surrounds the base of the branch. This is here to protect the cut branch from infection.
This article will help: https://www.gardeningknowhow.com/edible/fruits/oranges/pruning-orange-trees.htm