The Bad Practice of Topping
For more than 25 years, we have known that topping trees is one of the most harmful techniques you can do. Unfortunately, itís still one of the most common methods to be adopted by amateurs, professionals and large companies. Here we will uncover the reasons why it should be avoided.
What exactly is topping?
Topping is the random or indiscriminate cutting of tree branches to stubs. These stubs are not large or long enough to assume the terminal role. Once a tree no longer has terminal leaders, it can become a hazard, unstructured and vulnerable to disease along with other problems outlined below.
Topping is generally used to reduce the size of a tree. An owner may feel that the tree has become too large for the space is occupies or that it poses an unacceptable risk. Topping the tree is generally not a viable method of height reduction and will often cause more long term risk.
Topping stresses a tree
Topping a tree could possibly remove 50-100 percent of its leaf bearing crown. Remembering that leaves are the food factories for a tree, by removing them we starve a tree and trigger a survival instinct. The tree needs to put out a new crop of leaves immediately. To do so, dormant buds are activated below where each cut is made. If the tree has not saved enough energy to do this then it may die.
A tree with large open wounds is much more vulnerable to disease and infection. If it lacks the energy to defend against invasion the infection can spread and be fatal.
If you have read the pruning cuts article you will know that the correct place for cutting a branch is just outside of the branch collar. A tree is biologically equipped to close a wound such as this, provided it's healthy and the wound is not too large.
During topping, the cut is made further along the branch and the wound is not able to compartmentalize so the wood tissue begins to decay. If the badly cut branch is just a one off, the tree can usually close the wound without a problem but few trees can defend against multiple wounds caused by topping. Once decay sets in, there is a free path down the cut branch and into the main truck.
Yes, trees get sunburn; they are living organisms like us. Within a crown there are thousands of leaves that absorb sunlight. Once topped, the sun is able to penetrate down onto the lower branches and trunk, the parts of the tree that are often shaded. It may be hard to actually see sunburn because the real effect happens underneath the bark. However, it can lead to cankers, bark splitting and death of branches.
Once topped, the survival mechanism of a tree is to produce multiple shoots from below each topping cut. These may look innocent, but come at great expense to the tree.
The shoots actually develop from buds near the surface of the old branch; they are anchored in only the outer layer so are very weakly attached. The shoots will grow at an astonishing rate, up to twenty feet per year in some species. They often break off in windy and icy conditions. With such fast growing shoots, the original goal of reducing the height now becomes an issue again. However, the tree is now much weaker with a higher possibility of limb failure.
A trees growth is actually a calculated and complicated process; we may even call it a biological wonder. The fundamental aim of all species is the same; to present leaves to the sun in the best possibly away to allow photosynthesis to occur from sunlight. Topping removes the ends of branches, often leaving ugly stubs and destroying the natural shape of a tree. A topped tree will never regain its natural shape and will appear mutilated for the remainer of its time.
An Expense to You
Not only will you have to pay the person or company who tops your tree, there are further expenses that will occur:
More regular maintenance costs. If the tree survives the initial onslaught, it will likely require corrective pruning within a few years due to the aforementioned shoots. If the tree dies, it will likely have to be removed.
Reduced property value. As mentioned in the benefits of trees article, a healthy tree can add 5-20 percent to the value of property. Disfigured, ugly trees can be considered an eyesore and expense.
Increase liability. Because topping a tree will over time make it weaker, it may pose an unacceptable risk. Any damage caused by branch failure may lead to a finding of negligence on your behalf.
What can you do?
There is no doubting that sometimes a tree must be reduced in height or lateral spread. Maybe it has actually grown too large or is coming into contact with utilities. There are recommended techniques for dealing with this: Small branches can be taken back to their point of origin. Larger branches can be pruned back to a point that is suitable for the terminal role to be transferred. This method is usually called crown reduction; you can read about it here. A crown reduction helps to maintain the form, structure and strength of a tree. Proper pruning cuts will allow for compartmentalisation of the wound. Sometimes, the best solution is to remove the tree completely and replace it with a species that is more suitable for the site.
Thanks for reading.
SPC Tree Services