Make the right cuts when pruning trees
Pruning season is here, and today, here’s how you make proper pruning cuts on trees.
Any time you prune a plant, you are essentially wounding the plant. Good pruning cuts, particularly on trees, allow the plant to seal or compartmentalize the wound.
Tree wounds don’t heal, rather the tree “walls off” (compartmentalizes) or blocks decaying wood fungi from entering the tree through the wound. The tree develops a “wall” that acts as a barrier to these fungi, preventing further damage.
Physiologically, it’s more complicated than this, but you get the picture. Making a proper pruning cut on a tree is important to the overall health and structural stability of a tree. Of course, there are other factors involved in good wound sealing such as the overall health of the tree, but a good cut is always beneficial.
Topping, for instance, a poor practice at best, is when you remove the top of the tree and pay no attention to proper cuts. The result is a lot of new branches growing on decaying wood. This leads to structural problems in the long run.
The proper cut involves the bark collar and the branch bark ridge.
Look at the branch of a deciduous tree where a branch joins the trunk. The swollen part underneath the branch, right before the trunk area is the branch collar and has tissue to wall off wounds.
The other part to look for is the branch bark ridge. This is the line where the branch connects to the tree. Start the cut just outside of the branch bark ridge and cut through the branch, beyond the collar.
This ensures making the smallest cut possible, leaving the branch collar tissue to do it’s job in walling off or sealing the cut.
This is very hard to describe in writing. I am hoping this provides the basics for you to research and learn more.
I encourage you to view this Youtube video from our colleagues at Purdue Extension in the Forestry and Natural Resources Department: https://www.youtube.com/ watch?v=g3nxxsmnt6a.
Watch the whole video if you have the time, but to learn more about the above terms, go to around 39 minutes. Lindsey Purcell gives an excellent description along with photos.
Another important factor when pruning larger branches is to use the three-cut method. If you make one cut to a heavy branch, about the time you get almost through the branch, the weight will pull down the branch, potentially stripping bark from the trunk on the underside, resulting in a larger wound.
Homeowners can easily use these methods on small trees while establishing their structure. However, consult with a certified arborist when you need a large tree pruned. Structural stability is at risk if poor cuts are made.