~ Why Topping Hurts Trees ~
What is topping? Topping is the indiscriminate cutting back of tree branches to stubs or lateral branches that are not large enough to assume the terminal role. The most common reason for topping is to reduce the size of a tree. Often, homeowners feel their trees have become too large for their property and may feel that tall trees pose a hazard. Topping, however, is not a viable method for height reduction, and certainly does not reduce the hazard. In fact, topping will make a tree more hazardous in the long term.
Topping stresses trees, causes decay and can lead to sunburn. This sounds funny, but trees get sunburn too! Branches within a tree's crown produce thousands of leaves to absorb sunlight. When the leaves are removed, the remaining branches and trunk are suddenly exposed to high levels of light and heat. This can lead to cankers, bar splitting, and death of some branches.
Topping creates hazards because the survival mechanism that causes a tree to produce multiple shoots below each topping cut comes at a great expense to the tree. These shoots develop from buds near the surface of the old branches. Unlike normal branches that develop in a "socket) of overlapping wood tissues, these new shoots are only anchored in the outermost layers of the parent branches. The new shoots grow very quickly, as much as 20 feet in one year in some species! Unfortunately, the shoots are very prone to breaking, especially during windy conditions. The irony is that while the goal was to reduce the tree's height to make it safer, it has been made more hazardous than before.
What are the alternatives? There are times when a tree must be reduced in height or spread. Recommended techniques are to remove branches back to their point of origin. If a branch must be shortened, it should be cut back to a lateral that is large enough to assume the terminal role. This method of branch reduction helps to preserve the natural form of the tree. Sometimes, the best solution is to remove the tree completely and replace it with a species that is more appropriate for the site.
Our ISA Certified Arborists can help you determine the best tree care plan for your trees!