Exposed heartwood from sunscald or a wound is an open door to borers and rot. Keep the trunk protected for two or three years, or until the bark becomes woody. Small, leafy twigs eliminate the need for wraps. When finally removing vigorous unwanted branches, cut them almost flush with the trunk or to a collar if the branch has one. A collar is a swelling or ring around the base of the branch.
Collars are common on trees such as mulberry and sycamore.
The smaller the wound, the quicker the healing and the less chance of borer or rot infestation. Tree vigor is the most important thing in healing if the cuts are made properly. Refer to fact sheet F-6412, Fertilizing Shade and Ornamental Trees and Shrubs . Wounds of more than one inch in diameter can be treated with a pruning paint to help prevent borers. Do not use substitutes that might injure healing tissue.