Q.Willow Pollarding
While I was away on holiday, 3 same size(about 40ft high) riverside willow trees(each about 15ft apart, were to be pollarded. All have been done several times previously, together and at the same time. I have returned to discover 1 tree fully pollarded, another trimmed and the third not touched. An assessment by “3rd party surveyors” has been put forward as the very vague basis for this particularly unwelcome piece of butchery. There is no statement or explanation as to why such an exceptionally ugly process was deemed necessary. Is there any horticultural or arborial justification for such treatment or should we insist on getting the job done as before???I look forward to hearing from you.
Peter Morgan

Once you start the pruning method of pollarding, it will need to be continued.
https://www.gardeningknowhow.com/ornamental/trees/tgen/what-is-pollarding.htm