A300 Pruning standards recognize four basic pruning methods for pruning:
Clean: Selective pruning to remove one or more of the following parts: dead, diseased, and/or broken branches.
Thin: Selective pruning to reduce density of live branches
Raise: Selective pruning to provide vertical clearance.
Reduce: Selective pruning to decrease height and/or spread (consideration must be given to the ability of a species to tolerate reduction pruning).
Certain pruning practices are not acceptable and can injure trees:
Topping: The reduction of a tree's size using heading cuts that shorten limbs or branches back to a predetermined crown limit
Lion's Tailing: The removal of an excessive number of inner, lateral branches from parent branches.