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Hat racking, a drastic solution to recover runaway trees

A tree hat-racked in the previous years in view of pollarding.

In some cases, ornamental shrubs or trees neglected for a long time need drastic pruning to get back into shape.

Hat racking (or hatracking) is the most severe type of pruning. It is only suited to a very small number of tree species.

Hollies and boxwood are two tree types that can cope with undergoing hatrack pruning.

However, this technique should be avoided when proper pruning is possible since it’s very stressful for the shrub.

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Let’s now take a look at:

  • how to hat rack a tree,
  • which species should and shouldn’t be hatracked,
  • disadvantages of hat-racking vs other options.

How to hatrack a tree

Hat racking a tree literally means “turning the tree into a hat-rack“. So in the end, a shrub will look like a trunk with a few large stumps sticking out from it, without any leaves or twigs anymore. Ready for any giant to hang its coat on!

Steps to hat rack a tree

  • First, check that it’s really necessary. Often, it’s possible to get a tree or shrub under control by pruning less drastically over a span of time. Three years is common, with about a third of the tree cut back every year. Short of cutting the tree down at the trunk, nothing is more stressful to your shrub.
  • Second, although the idea seems simple, performing it may be tricky. After all, you’re dealing with sawing off large branches high up in a tree. It’s essential to ask a professional to hat rack your runaway shrub if ever it involves a chainsaw or if it requires use of a ladder or platform. Your life is worth more than a beautiful shrub!
  • Once you’ve assessed this, here is the procedure to hat-rack the shrub.

Procedure to hat-rack a tree

  • The best season to hatrack a tree is spring, just after the last frosts.

1. Whenever multiple trunks have formed, cut down all but one (the most vigorous one). Multi-trunk growth is common in yaupon, lilac and holly.

2. Determine the height you’re targeting for the tree. Perhaps you’ll cut it down by half or by a third.

3. Determine how wide the largest lower branches of the tree should be. Usually you’ll cut them back to only several feet, or about a third of their original length.

4. With the lower branches cut, and the tip removed, visualize a pyramid or a cone. The cut tip of the tree is the tip of the shape, and the shortened large lower branches are the base.

5. Cut all remaining branches so that they fit within this cone or pyramid.

6. Eventually, cut some branches all the way back to the main trunk if you want to lighten up the tree even more.

You’ll be left with only a skeleton that seems hacked bare. It’s surprising, but from these branches new twigs will sprout and bear leaves.

  • Note: you won’t be having any flowers or berries the first year after hatracking!

Which species of trees can be hat-racked?

Hat racking should only be performed on dense, bushy shrubs that have grown too tall. Typical shrubs are holly, yaupon and boxwood.

The following species of trees can be hat racked and will bounce back:

Any other type of tree or species should not be hat racked! In many cases it will shock and kill the tree, and if it survives it will need years to recover.

You should not hat rack oak, birch, beech, ash, and many more, unless you diligently maintain them as pollard trees.

Also, you should never hat rack a tree if you intend for it to grow taller than a person. Weaker regrowth means that any person walking beneath it is at risk of having a branch break while under the tree!

Hat racking in tropical countries

Many tropical tree species are very vigorous and will survive hat-racking. However, it’s preferable to resort to crown reduction. Crown reduction is the best way to “shrink a tree”!

Disadvantages of hat racking

Hat-racking is generally not suited to very large trees. For shrubs and bushes, disadvantages are minimal, but serious issues arise for large ones.

New wood grows back weaker

Indeed, branches that grow back from the remaining stumps are much weaker. Since they take off at an angle from the cut on the bark, fibers in the wood are neither aligned nor continuous.

As the tree grows, this is covered up with bark and thickens, but if loaded with snow, a swingset, or simply strong wind, the branch may snap.

  • Hat-racked trees are more dangerous.

Hat-racking requires follow-up pruning

This is true for flower vines and grape vines. A consequence of cutting a branch sharply is that no “leader” branch naturally channels growth anymore. Instead, many small twigs pop up around the cut and crowd each other out.

To bring the tree back to a single branch again, a pruning follow-up is needed every year for two or three years. Each time, a leading twig is selected and all others are removed.

  • In the special case of pollarding, branches are cut back to the original cut every few years.

More expensive despite a low initial price

Hat-racking is sometimes said to be cheaper than a proper pruning. This may be true because hat-racking doesn’t require any skill apart from knowing how to use the cutting tools.

  • In the long run, however, it’s always preferable to ask for a more skilled hard pruning or tree thinning instead.
  • Not only will this not require much follow-up pruning, it will also avoid costly accidents!

Hat racked trees are more vulnerable to disease

Diseases like fungus enter the tree through wounds.

Open cuts also make the tree vulnerable to late frosts, if ever the hat racking was performed too soon.

Hat racking trees is sometimes illegal

In some places hat racking is illegal or restricted. There are several reasons for this. Trees that are hat-racked have weak joints when they grow back, as seen above. This makes the practice dangerous, especially in parks and such.

A second reason is that hat racking interferes with land value. Simply put, a hat tracked tree is considered ugly for a few years. This brings property prices down. Home Ownership Associations sometimes forbid hat racking for this reason. Remember to ask if it’s authorized where you live for large trees.

Alternatives to hat rack for an overgrown tree

The best is simply to prune your tree regularly. It’s perfectly possible to keep a tree at the same size for decades by pruning it diligently.

If you do have to remove a large branch, always carefully consider where the cut should be. Ideally, cut just above a node or an existing split, so that the remaining (smaller) branch can absorb growth naturally. When you do this for all the large branches of a tree, it’s called crown reduction.

  • Crown reduction is just as effective as hat-racking and much softer on the tree  – and on the eyes! The natural form of the tree is retained.

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Image credits (edits Gaspard Lorthiois):
CC BY 2.0: Julie Corsi
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  • James wrote on 8 August 2021 at 4 h 34 min

    Hat Racking is not a real term used by any real arborist. You are essentially pollarding the shrub or tree. Then you are advising people to prune their plant from that point instead of continuing the pollarding practice.

    I am confused as to why you would make up, or use the wrong term, when in your article you mentioned the proper term pollarding many times. So weird.

    • Gaspard wrote on 11 August 2021 at 10 h 02 min

      Hi James, it’s not a common term mostly because it’s not a common practice, especially because arborists themselves wouldn’t be caught red-handed doing this. I agree with you! However, it is used to describe the fact of topping a tree and cuttings its branches in the manner described. This is often simply to state that it’s prohibited or not allowed in local regulations or in neighborhood guidelines.

      It’s different from pollarding because when you pollard you intend to keep the same structural branches and regularly cut off growth from that point on afterwards. Hat-racking is typically a one-time action, that shouldn’t be repeated, and instead, the better technique of pruning to shape the tree is followed. The cuts that result from the hat-racking are gradually eliminated thanks to proper pruning.