The most important thing to know about what part of tree not to cut is the branch collar. This small swollen ring sits where each branch meets the trunk or a larger limb. Cutting into or through this collar causes lasting harm that your tree may never recover from.
I have two apple trees in my backyard that taught me this lesson years ago. One tree had branches removed with clean cuts just outside the collar. The other had flush cuts made right against the trunk. After five years, the first tree shows smooth healed bark over every old wound. The second tree still has open wounds with decay spreading into the trunk wood.
My neighbor made similar tree cutting mistakes on his pear tree. He trimmed branches flush to make it look neat. Three years later, soft rot had spread so deep that a major scaffold branch snapped off in a storm. That single bad pruning choice cost him half his tree.
The branch collar holds special cells that know how to seal off damage. When you cut outside this zone, your tree builds walls of resistant tissue around the wound. This process keeps decay and disease locked out of the healthy wood. Cut into the collar and you destroy this natural defense system.
Good branch collar pruning keeps all the healing tissue intact. Bad cuts remove it and open a door for trouble. Fungal spores land on the exposed wood and start breaking it down. Bacteria move in and spread through the tree's inner tissue. Once decay gets past the collar zone, nothing stops it from moving deeper.
You can find the branch collar by looking for a slight bulge or ridge where the branch connects to larger wood. Some trees show it more than others. Oak and maple have obvious collars. Apple and pear collars can be subtle but still exist. Run your hand along the branch base and feel for any change in the angle or thickness.
Position your saw or loppers just beyond the outer edge of this swelling. Angle your cut so it slopes away from the trunk but stays parallel to the collar ridge. This leaves all the healing tissue in place while removing the unwanted branch.
Never leave a long stub sticking out either. Stubs die back and invite the same decay problems as flush cuts. The goal is a clean cut just outside the collar with no extra wood left behind. Your tree will thank you with fast healing and strong defenses against rot and disease.
Read the full article: Pruning Fruit Trees: A Complete Guide
