Incorrectly pruned evergreen shrub.
Stubs on this 'topped' oak tree forms spindly suckers. These trees are now weak, stressed, and ugly.
Pruning is sometimes necessary to improve plant health. The only time pruning might not be needed is when a natural woodland area is desired.
In this case, dead branches and dead trees can be left to provide perches, nesting sites, and other desirable benefits for pollinators and birds.They become part of the natural nutrient cycling process in the landscape. Note, however, to occasionally check for any disease or pest outbreaks in these areas.
If a more manicured look is desired, then pruning should be performed to increase air circulation and sun into interior of trees and shrubs. Make sure to make clean cuts. Ragged and incorrectly cut branches can be entry sites for disease organisms.