What structure is formed when trunk tissue grows around branch tissue?

The structure formed when trunk tissue grows around branch tissue is known as the branch collar. This anatomical feature is crucial for the health and stability of the tree. The branch collar acts as a natural defense mechanism; it contains specialized cells that help in the healing process and can effectively seal off wounds caused by branch growth or eventual branch removal. This sealing process helps prevent decay organisms from entering the trunk and promotes proper growth around the junction.

The branch union refers to the area where the branch and trunk meet, but it does not specifically describe the tissue growth process. The branch base denotes the bottom of the branch where it attaches to the trunk, while the branch point generally refers to the location where a branch or twig originates. Understanding the role of the branch collar in promoting tree health is essential for proper tree care practices, especially when it comes to pruning and managing tree structure.