Pollard
A frequently misunderstood term, and used in two different contexts.
Traditionally and still commonly used this term describes the removal of all branches from the trunk.
Mature trees that have not been pollarded before are generally not suitable candidates for this type of pollarding due to the large wounds that such treatment produces which may jeopardise the long term future of the tree.
A less frequently used definition can mean the regular (annual of biannual) pruning back of small branches to the same point resulting in the formation of a ‘pollard head’. Pollarded trees usually require regular treatment of re-growth.