Topping is the most harmful tree pruning practice known. Yet despite all the information available, it remains a common practice among local tree companies and the homeowners who hire them. Topping has become a major threat to the urban forest, shortening the lifespan of trees, reducing canopy coverage and creating hazardous trees in high-traffic areas.
What is Topping?
In simple terms, it is the drastic removal of all parts of the tree above a certain height, with no regard for the structure or growth of the tree.
Why is Topping Terrible for Trees?
Wounds cause by topping expose a tree to decay and invasion from insects and disease. Also, the loss of foliage starves the tree, which weakens the roots, reducing the tree's structural strength.
Topping often removes 50 to 100 percent of the leaf bearing crown of a tree. Because leaves are the food factories of a tree, removing them can temporarily starve a tree. The severity of the pruning triggers a sort of survival mechanism. The tree forces rapid growth of multiple new shoots below each cut to put out a new crop in order to quickly to compensate for the missing canopy and food source.
These new shoots come at a great expense to the tree. Unlike normal growth, these new shoots are anchored only in the outermost layers of the parent branches. The new unstable shoots grow quickly, as much as 20 feet in one year, in some species. Unfortunately, the shoots are prone to breaking, especially during windy conditions. The irony is that while the goal was to reduce the trees height to make it safer, it has been made more hazardous than before.
Topping is Expensive and High Maintenance.
Because of its unnaturally accelerated growth, a topped tree must be pruned again and again, and eventually removed when it dies or becomes too hazardous. Much like the many headed Hydra snake that Hercules battled, when a tree is topped, people create maintenance monsters in their back yards.
Topped Trees are a Liability.
Because Topping is considered an unacceptable pruning practice, any damage cause by branch failure of a topped tree may lead to a finding of negligence in a court of law.