This is a pruning system that involves the removal of the upper branches of a tree, to promote a dense head of foliaged branches.
It is normally started once a tree or shrub reaches a desired height, and annual pollarding is recommended as it will restrict the plant/tree to the height you want.
When do I pollard a tree?
When a tree or shrub reaches a desired height.
To help the tree last longer than a naturally grown tree.
If a tree has been previously pollarded.