Should I paint or seal a pruning cut?

Many people grew up believing a pruning cut needs tar or paint. Research summarized by university extension services has not shown that it helps most trees, and it can sometimes trap moisture against the wood.

What helps is where and how the cut is made. A branch grows out of a slightly swollen ring called the branch collar. The cut should be just outside that collar, not flush with the trunk and not leaving a long stub. A clean cut in the right spot lets the tree wall off the wound by itself.

Tools matter too. Sharp, clean tools make cleaner cuts.

If you have a special case, such as an oak in a region with a known disease risk, local extension offices may give advice for that situation. Ask them or a certified arborist.