Tempted to prune? Know where and how to cut for a healthy, long-lasting tree

Not only does the tree sap start to flow when the weather warms up, so does the urge to prune. It has been said pruning might be the best but worst maintenance practice.

Pruning trees improves aesthetics, structure and safety. Removal of dead or damaged wood reduces failure, which can lead to property damage or bodily injury.

Trees are genetically geared to grow to a certain height and width, so cutting the branches back is not the answer to control size. Pruning slows growth, but over time, pruning alone will not solve the problem.

Trees that are too large for the space should be removed and an appropriately sized tree planted in its place. Topping a tree is never the answer.

Before making the cut, it is important to remember that pruning is the selective removal of plant parts to improve overall growth. Just like in humans, a cut creates a wound that sometimes lead to problems like insects and disease. A pruning wound adds stress to the tree, requiring it to use food reserves and energy.

It is essential to minimize the wound and any damage, allowing the tree to quickly seal off the cut. The smaller the cut, the less damage.

Branches should be removed if possible before growing large. Limbs in the 2- to 4-inch range recover and close over, but larger limbs may never close over, leading to rot and decay, shortening the tree’s life.

Trees seal off a wound through a process referred to as CODIT, compartmentalization of decay in trees, reducing the chance of pathogens to invade. How well a tree can do this is dependent on species, age, health and other factors.

The goal is for the tree to grow callus tissue, or a new bark layer, to enclose the wound and reduce decay. Pruning paints or wound dressings slow this process and should not be used.

A proper cut is vital in allowing the CODIT process to work. Improper cuts result in more exposed wood, a stub, or torn bark, which increases the wound size making it harder for the physiological process to naturally occur. Here is how to tell where to cut.

Pruning should always occur at a branch or crotch angle. Look for the bark ridge, the raised and rough growth of bark on the topside of the branch to be removed.

Next, look for the branch collar at the bottom of the limb. This will be a wrinkled looking layer of bark. Make the cut just to the outside of the ridge extending down to the outside of the collar. At this location, the tree stimulates the branch protection zone to seal off the wound.

Where to make the cut is just one step. What to remove and when are other challenges. Knowing where to make the cut helps in achieving your goal of a healthy, long lasting tree.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Have a question for him or other university extension experts? Email them to garden.help@jocogov.org.