Question: How much of a stub is too much when you’re removing a tree limb?
Answer: If you look closely at any large limb, you’ll notice that it swells just as it attaches to the main trunk. That’s an area known as the “branch collar,” and it’s a very important part of the healing process. Rather than cutting exactly flush with the trunk, you need to leave that one-quarter-inch branch collar in place. Any more stub than that and you risk decay setting back into the trunk.