Established trees often require very little pruning over many years. Sometimes the amateur can deal safely with the removal of dead, damaged or diseased branches, which is the principal operation that needs to be carried out. However the scale and mechanics of much of the tree pruning makes it potentially hazardous. The removal of large branches damaged by storms or snow that cannot be dealt with from ground level, or any tree work that is carried out close to power lines should only be tackled by experienced tree surgeons.
The easiest way of reducing overall height and spread of trees crown is by cutting back selected branches to lower limbs or laterals, while retaining the natural shape of the tree. After pruning, the tree will make fresh extension growth and so to maintain the crown at its new height this operation needs to be repeated on a regular basis, in some cases as frequently as every four years F95zone .
To lift the crown you need to remove some of the lower branches or other laterals, and this can often be relatively straightforward. This is generally best carried out when the tree is young, but on older trees the weight of the lower branches tend to bring them down and may result in a number of problems including shading, obstruction of access, and the blocking of views.
The lopping of side branches and the topping of the main trunk are crude methods of reducing the height of trees that have become too large for the positions in which they were planted. Typically they are used by unqualified people claiming to be experienced tree surgeons. The lopping and topping are not recommended as methods of pruning, they destroy the natural shape of trees and are frequently the source of major problems. The large wounds that they create can often lead to serious decay, which is not always easily detected.