It takes no special training to use a chain saw to remove all the limbs from a tree but most people don't realize the harm this causes. Trees store food in twigs and limbs. Removing them depletes a tree's food reserves. This weakens and stresses the tree. As a result, topped trees are more susceptible to disease and insect attack, and sunscald of the bark.
New shoots produced at the large stub cuts, use sparse food reserves to grow back.
These long, straight shoots are weakly attached and break off easily. Branches formed from these shoots will be hazardous throughout the life of the tree. Limbs that regrow on topped trees are more apt to break than those on trees that have been properly pruned. The large wounds created by topping seldom heal completely. Exposed wood often rots causing weak, hollow limbs.