While tree topping seems like a quick, simple solution to overgrown trees, it can be a potentially dangerous practice that can cause significant and permanent damage to the tree itself and the property around it. A better, more sustainable option is called crown reduction, which can be completed to decrease the overall crown size of a tree without compromising the overall health or stability of the tree.  The general rule of thumb is that no more than 30% of the canopy should be removed .