One of the most common reasons why people decide to prune their trees is because they are deemed too large. But unfortunately in many places on Earth, people make cuts on the branches or stems without regard to their size, foliage, bud allocation or tree response. If you're thinking of reducing your tree’s size, come and learn about this unacceptable practice first.

Topping is when live branches and leaders are cut to stubs (usually large enough to contain heartwood), without regard to bud allocation, the effect to long term tree health or structural integrity. 

You often can recognize it when landscape workers have neither the knowledge nor the right equipment to make proper cuts and  simply butcher the main branches, usually with a chainsaw, where it’s comfortable and easy for them to reach. 

The problem with this practice, besides the unaesthetic view it leaves behind, it its impact on the tree's health. When cutting away such an excessive amount of live wood, a great amount of stored carbohydrates are taken away from the tree as well as the foliage producing them. When the complete foliage is removed from the branches, the nutrient, water and hormonal circulation is destroyed and most of the time dieback occurs. The extent of it heavily depends on the species, the amount of foliage removed, the health and the age of the tree. Older, weaker trees usually affected worse than young, healthy specimens. 

Dead and exposed wood are a great entry point for opportunistic wood damaging pests and pathogens that further stressing the tree. They draining the tree’s energy bank to fight against these organisms, which further weakening it’s structural integrity by decaying affected tree parts.

As soon as the tree recognizes the missing foliage, it will try to replace it. However the original structure cannot be replaced and most of the time, so called epidemic shoots emerge around the surface of the wound or further back on the stem. These shoots are usually rapidly and densely growing in an upward direction.

So while topping is a quick and easy way to get to the desired results of a smaller crown size, this success is only temporary. The shoots that are emerging near the heading cuts, soon will be as long as the original structure but will create further problems. Headed trees are looking (and soon will be) sick, unhealthy and unsightly. The mistreated trees are not only aesthetically affected but their structural integrity is compromised as well becoming higher hazards and liabilities. Epidemic shoots are only connected to the annual ring when the cut has been made, therefore missing the overlapping connection at the “union” which makes it a weaker attachment than the original branching. This leads to an increased risk of failure when they become branches. The risk of failure is going to be greater if the headed wound can’t be sealed and/or compartmentalized and the wood starts decaying. This is very common.

If the topping is too severe or the specie is less tolerant for this kind of practice tree death is a common occurrence within a year of the “treatment”.

Because of these serious consequences, without an acceptable excuse most tree care associations revoke their certification from arborists they catch doing this practice. In some countries such as Germany people can be judged in court and be legally banned from their profession if found guilty.

While it is discouraged in every levels to top trees, exceptions can be made in 3 specific cases:

Storm damage:

 When a tree has suffered significant damage from storms, such as broken or severely injured branches, topping might be used as a last resort to mitigate hazards and save the tree. However, the cuts should be made with careful consideration of the tree’s long-term health and safety.

Previous failure: 

If a tree has experienced a structural failure in the past, such as a large branch breaking off, topping might be the only choice to save a significant branch or the whole tree.

Gradual tree removal: 
Sometimes, trees need to be removed gradually due to their importance to the landscape or community. In these cases, topping can be part of a phased removal plan, where the tree is reduced in size over time to minimize risk and prolong the lifespan of the remaining tree.

First and foremost do nothing for 2 to 3 years. After this stressful treatment trees need time to heal, adapt and restore their energy reserves. After the initial recovery period select 2-3 shoots to retain behind the surface of the cut and remove the rest of them. The retained shoots will help to rebuild the tree’s structure on the long run. 

Guide the retained shoots outwards from the center of the tree and away from each other. Make sure none of them touching or crossing an other one. If they are too long (50-100x the diameter of the shoot, measured at the base of the union), shorten them to promote branching and reduce the risk of breakage.

The restoring process can take from a few years to decades and depending on the severity of the intervention the tree may never fully recovers. 

In cases where the damage from the topping is too severe, or the tree’s health continues to decline, it might be best to remove the tree entirely and plant a new one.

The main source of the problem is human desires. People use topping as a size managing technique (as presented before only with short term success). Therefore we can look at the different size management techniques to replace this harmful practice. 

Plant well:

The cheapest and most effective approach is to select and plant appropriate species to the location. In a small garden or dense neighborhood it’s almost guaranteed that a large growing tree would cause conflicts all the time. Therefore if a tree is definitely desired on the landscape, use species that are staying small, even at maturity.

Use plant growth regulators:

If the wrong kind of species has been established but conflicts have not yet arisen, the use of hormonal plant growth regulators can prevent or delay such inconveniences. These can be applied to manage tree growth without the need for drastic pruning measures. They help control the size and shape of the tree in a more natural way.

Make appropriate cuts at the right location: 

Regular, proper pruning practices can help maintain tree size and health without resorting to topping. This involves making selective cuts to remove specific branches while preserving the overall structure and vitality of the tree.

Pollarding:

This is a centuries old pruning technique where relatively small heading cuts are applied on an established branching structure and every year or two the arising shoots around the wound are cut back to the same point. Eventually, a knob of tissue will develop at the location of the cuts. These are called pollard heads. While pollarding is not suitable for all species, it can be an effective way to manage tree size if done correctly.

Do nothing, appreciate the size of the tree, monitor risks: 

Sometimes, the best action is to let the tree grow naturally and simply monitor it for any potential risks. Appreciating the tree’s size and form can create a healthier and more aesthetically pleasing landscape if the conflicts are negligible.

In many places, tree topping is illegal due to its detrimental effects on tree health and structural integrity. Understanding the negative impacts and consequences of this practice, a responsible arborist will never top a tree, even if requested by a customer. Instead, consulting with an arborist about your options can lead to better, more sustainable solutions for tree management. Always consider the long-term health and beauty of your trees and seek professional advice when needed.