Here are 2 photos of Oak trees that have been pollarded at some stage in their life,
The first one is a lapsed pollard found in Centre Vale Park Todmorden, which has suffered greatly from the shading of self-seeded trees close by. Oaks need plenty of light and space.
This Oak would have been in the open when it was younger and is a good indicator of what the landscape was like before woodland arrived. It is full of character and one can look at it for ages trying to work out how it got those bulges and folds on the trunk.
The second Oak is in a nearby wood but is not subject to as much shade. It has been re-pollarded and shows the fresh spring of new shoots. These new shoots can be allowed to grow for any number of years before being re-cut but 10 to 20 years gives good sizes for lots of uses.
There are plenty of lapsed pollards of many species in the Calder Valley and it can be fun trying to spot them. Because of this method of management, the trees as they age create many more niches for wildlife than a 'woodland' tree.