This is what your tree should never look like. This is the result of the abysmal practice of topping. Other names for topping include: heading, tipping, hat-racking, and rounding over. Besides the ugliness of the topped tree and the cost of having someone come do it every year, there are other reasons to not ever do this to your tree.
The International Society of Arboriculture states: “Topping is perhaps the most harmful tree pruning practice known. Yet, despite more than 25 years of literature and
seminars explaining its harmful effects, topping remains a common practice.”
There are several things that topping your tree does to harm your tree:
Stresses the tree – Making large cuts can remove more than 50% of the leaf bearing crown of the tree. In an effort to recover, the tree produces rapid growth of new leaves. As a result you leave a weak tree with large pruning cuts which provides a perfect situation for diseases and pests to attack the tree.
Decay – Correct pruning of a tree allows the tree to compartmentalize the wound and close it. Topping leaves no way to close the wound created by leaving no branches nearby to carry resources to the point of the cut.
Weak Limbs – Due to the stressful production of new branches after topping, the newly formed branches are much weaker than a properly formed branch. This increases the risk of breakage through windy conditions.
While topping is still commonly practiced, it is not necessary. If you need clearance from utility lines you can prune in a responsible way to satisfy clearance and still provide a way for the tree to heal itself. Proper planning of tree species and placement will help you to avoid these problems in the first place.
Fruitless Mulberry trees have a lifespan of 50 years, but generally only live for up to 25 years due to topping. Topping is much easier than properly pruning a large tree and provides yearly income for those performing it, but properly pruning your tree will result in a healthy tree for much longer.