What is the branch collar?

• A. The tip of the branch.
• B. The outer bark where the branch meets the trunk.
• C. The swollen area at the base of a branch where it attaches to the trunk.
• D. The inner cambium layer of the branch.

Answer: (C)

The branch collar is the swollen area at the base of a branch where it attaches to the trunk, formed by the tree as it grows protective tissue to seal the wound. This zone helps protect the union and provides the starting point for callus tissue that winds around the wound, aiding healing and strength. When pruning, you want to cut just outside the branch collar so that this healing tissue remains intact and can effectively seal the cut. The other descriptions don’t fit because the tip of the branch is just the end of the limb, the outer bark at the junction is not the specialized healing region, and the inner cambium is a very thin layer, not the expanded protective area at the branch-trunk connection.