Do you ever wonder why a tree didn’t grow well, looked deformed, fell over, or entirely died? There are certainly combinations of reasons for this happening, but according to many horticulturalists, one of the top reasons is improper pruning. Specifically, a damaging practice called “Topping”. Topping involves cutting away a large section of the top of a tree’s crown, or all the leafing branches across the top half of the tree. This is often justified by the need to reduce the overall size of a tree. The leader (or the vertical stem) and the upper primary limbs (known as scaffold branches) on a mature tree are often cut back to a level height- This can prove damaging or fatal to many trees, or severely decrease their longevity.

Why not to Top a tree:

1. Weak, unhealthy shoots and mini limbs without a central leader will sprout as a response to the trauma. The tree becomes weak, top heavy and inevitably the wrong shoots or stems will dominate the tree. The limbs will be weakened both aesthetically and structurally. Eventually, a tree trimmer will need to come back and remove most of the shoots costing more time and expense than doing it right the first time.
2. Shock, Trauma and starvation can occur as the leaves that provide food and shade to the rest of the tree are removed the recovery process is slowed. Without protective leaves, the tree lacks nutrition and often the new growth and bark are scalded by the sun. The tree’s energy goes into recovery, self-protection, and producing unnatural new growth while branching.
3. Large wounds create a magnet for insects and disease. The shock and starvation that occurs reduces the trees natural ability to fend off insects, disease and decay. Once decay hits a tree, there is no way of stopping it.
4. Weak Limbs and a weak tree can be dangerous. The meeting point of the limbs and trunk is called a “crotch”. Crotches growing at wrong angles and with competing branches create weak forks and brittle wood that breaks easily. Unhealthy trees and limbs are much more likely to fall down in times of stress or inclement weather
5. Increased cost, increased liability and lost aesthetic value. Though it may be tempting to take that low cost of the simple large cut, certainly more money will be invested in repair of the tree, removal of dead or broken limbs ,and damages caused by the inopportune falling of limbs and trees on items of value. The value a beautiful tree can add to a property cannot be taken for granted, and the cost of replacing a tree of size may be impossible if not very expensive.

Of course, there are exceptions to this rule, as some trees that are often used as hedges respond well to topping if we want to keep them as hedges. If a tree is to be kept like a large shrub at a limited size, topping is actually necessary, but if the tree is to grow into its natural state as a tree, then the above rules apply.

So, what is the alternative when the tree is too large? Crown reduction is the preferred pruning method, because it conserves natural appearance, decreases need for extensive pruning, and limits stress.

Read our next article on crown reduction!

– Mark Meahl

In our last article, we described the 5 reasons that you should never top your tree. Not only can the practice be damaging to the tree, and expensive in the long run. But what are we to do if it is necessary to reduce the size of a tree?  Most arborists agree that Crown Reduction is preferred to topping. Compared to topping, reduction helps maintain the form and structural integrity of trees.

To recap, Crown Reduction is the selective, strategic removal of branches, all the way back to healthy growing lateral branches. This practice aims to develop a new central stem leader at the top of the tree. To help empower you in this process, we’ve cut through the clutter to find the top five basics of Crown Reduction.

The 5 Basics of Crown Reduction

1. Use the “Drop Crotch Pruning Technique” – selectively pick branches, and cut back to a lateral branch or trunk, which looks like a junction of two legs, or the crotch. Never leave large stubs behind.
2. Never cut off more than 20% of the tree. If it’s necessary to prune more than 20%, either because of damage or dangerous conditions, trim the tree in increments. 20% now, then a healing period, and you can finish the job at a later date- Usually about a year later, if you can.
3. Develop a new central leader at the top of the tree. The new central leader should be the tallest, straightest, healthiest stem in line with the rest of the trunk.
4. When reducing a leader branch, cut back to a lateral branch that is large enough to assume dominance. A lateral branch that is 30% of the size of the original parent branch will be your ideal candidate. Any larger than the 30%, and you run the risk of producing multiple, weaker shoots, that do not follow the intended pruning direction- Any smaller, and the branch may not be strong enough.
5. As a general rule, when reducing the size of the tree, one should try to thin out the longer branches while keeping the crown of the tree balanced.

Mature trees are a valuable resource that are not easily replaced. Careful, well thought-out pruning may cost a little more in the short run, but is well worth the effort in long term health, aesthetics, safety and future costs associated with the tree. If you are hiring a tree professional to do the job for you, be sure they are familiar with the above techniques. If you are trimming the tree yourself, be careful, and educate yourself on the most important pruning basics.

In our previous articles, we discussed the negative side effects of topping pruning, specifically topping trees. One exception is hedges; it is necessary to top them so they do not grow into tall trees but into aesthetically pleasing green walls.

I remember as a kid reading the book Robinson Caruso, about a shipwrecked man on a desert island. Struggling to survive on his own, he builds a sheltered enclave by planting trees close together in order to create a barrier which offered protection and hid him from the dangers around him. Today in our crowded world, the saying “fences make good neighbors” couldn’t be truer… But maybe even better of a saying is, “hedges make great neighbors.” Hedges provide privacy along with a soft, organic, and aesthetically pleasing barrier between us and our neighbors.

Hedges don’t just happen. In most cases, we can’t plant a tree or shrub and expect it to stay dense and aesthetically pleasing without some effort on our part. The two general categories of hedge candidates are either large shrubs that grow large, or trees that respond to topping-pruning by generating new growth along the trunk.

While the first category, shrubs, are generally lower maintenance once mature, they take a long time to grow into fences. Tree-type hedges generally grow faster, so are often more popular. However, the tree-type hedges can’t grow into proper hedges without help from us. This is where topping comes in. The first rule of pruning is, “Cut a plant in one place and it grows in another” couldn’t be more obvious than this case. Topping your tree-type hedge on a regular basis encourages them to put their energy into the lower growth, shifting focus away from their normal job of growing tall, generating dense, low growth, perfect for making a fence-like hedge. Remember to top your tree-type hedges often, as waiting too long between topping, or cutting only the sides, will result in a less dense plant. See examples below of two properties with the same plant (Ficus nitida). One has been topped, the other has not.

When planting a new hedge, don’t let the plant grow upward to the desired height immediately. Allow the plant to grow in 1-foot increments, then cut back 4 inches. This forces new limbs closer together, which will create that compact, dense look, without compromising health.

While we may not be hiding from wild animals or cannibals like Robinson Caruso, with mature hedges in place, we can enjoy our yards in peace, quiet, and any state of undress without upsetting our neighbors.

Mark Meahl