Ask a Master Gardener: Please, no more topped trees!

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(Posted July 1, 2021)

By Jane Kutzley, Madison County Master Gardener

A mature shade tree is an entire balanced ecosystem, all in one very attractive package. The roots and branches grow and spread in beautiful harmony. The roots support the tree physically and send water and minerals to the farthest leaf on the tallest branch. The leaves, in turn, manufacture starches through photosynthesis, providing energy to expand the root system and power the entire cycle. The tree continues this balanced cycle throughout its life. A tree is either growing or it is dying.

Anything that causes damage to the tree will disrupt that harmony and send shock waves throughout the system. If the damage is not too severe, the tree will try to heal over the damaged area and reach a new equilibrium. It will often continue to live a long, healthy life after overcoming such an event. These trees often have a beautifully imperfect shape.

Topping is the practice of removing many large branches in an attempt to limit a tree’s size. It causes shock and damage that cannot be repaired. When the canopy is severely reduced by the removal of many large limbs, there is no longer sufficient leaf cover to sufficiently support the root system. The root system starves and will shrink in size, reducing critical support for the tree. Additionally, the many open wounds created by the cuts are an invitation to fungal disease, insects, and decay.

Regular tree limbs grow slowly over years and are attached to the parent branch by a band of tissue that increases in girth and strength every year as the limb grows. After topping, the tree tries desperately to establish a new equilibrium. In order to produce new leaves quickly, the tree will send up many long vertical sprouts from just below the cut edges. The new sprouts are an attempt by the tree to reestablish the canopy it desperately needs to survive. These shoots are thin and weakly attached to the tree limb and many will break in a strong wind. The new shoots grow so rapidly the tree usually reaches its original height in just a few years but the shape of the tree has been destroyed. In addition, due to the lack of leaves and the resulting reduction in photosynthesis, the tree will lose a portion of its root system and a similar share of its physical stability.

Quite often, in a few years, the tree will succumb to disease or to high winds because the root system has shrunk, reducing stability. Because it has been a few years since the tree was topped, the death of the tree will be attributed to other causes, or the homeowner may feel vindicated because they were certain the tree was going to fall eventually. Even if the tree continues for 10 or more years, it will never achieve the lifespan it should have enjoyed. The trauma is just too great. Some trees, such as beech, will not tolerate topping and will usually succumb within a growing season.

Judicious, thoughtful pruning of a large tree is the much better alternative. Secondary branches are selectively removed, the tree’s shape and integrity are maintained, the canopy is opened up so wind and sun can pass through, and the tree recovers quickly from a far less traumatic event. Pruning should only remove between a quarter to a third of the canopy and should be scheduled every three to five years. A reputable, knowledgeable arborist should be used.

Sometimes, as when a large tree is planted under power lines, there is no choice but to top a tree. Other times, the tree has been planted too close to a house or drive. Consideration should instead be given to removing the tree. The money spent on topping would help pay for removal and replacement with a tree that will be more suitably sized when mature or is better located to allow for mature size.

One last consideration: a topped tree is visually ugly, especially for the six months of the year when it is leafless. According to a quick internet search, a beautiful, mature tree will add between $1,000 and $3,000 (one source said up to $10,000) to the value of your home. Seems a shame to throw all those dollars into a wood chipper.

To learn more about the effects of tree topping, go to www.extension.purdue.edu/extmedia/FNR/FNR-FAQ-14-W.pdf.

For more information about the Master Gardeners program, call OSU Extension at (740) 852-0975.

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