In the past the practice of lopping or topping to reduce the overall height of a tree that was becoming inconveniently large was an accepted practice. Unfortunately, though still regularly done by homeowners and some operators, it is no longer viewed as best practice, and can sometimes have the reverse effect, encouraging subsequent regrowth at weakened points of the trunk, resulting in a larger and more dangerous tree. Exactly the opposite of the desired effect! The crown of the tree is extremely important to the overall structure, and trees naturally monitor the ratio of their growth zones to the load bearing capacity of their major branches. Proper pruning by a trained arborist tries to maintain these ratios, reducing the height of the tree in the least stressful way possible.