Height Reduction pruning, also called Crown Reduction Pruning or Drop Crotching, is most often used when a tree has grown too large for its permitted space whether it be from powerlines, structures, or view concerns. This method is preferred to topping a tree because it results in a more natural appearance, increases the time before pruning is needed again, and minimizes stress. A tree’s size can be reduced by up to 1/3 using this method.
Crown reduction pruning is a method to be used sparingly because it can result in large pruning wounds to stems that may lead to decay over time. Sometimes, a better long-term solution is to remove the tree and replace it with a tree that will not grow beyond the available space. More information on Tree Removal here.