From Longman Dictionary of Contemporary Englishpreservation orderpreserˈvation ˌorder noun [countable] SCLin Britain, an official order that something, especially an area of countryside or an old building, must be preserved and not damaged a tree preservation order
Examples from the Corpus
preservation order• Those particular flats have a preservation order on them.• With that, the council slapped a preservation order on it.• Penryn itself is unspoilt, and its old and narrow streets are under a preservation order.• Indeed, listing is in essence a collective preservation order.• Tree felling: Trees near a house in Hawkswood could be felled despite a tree preservation order.• The tree preservation order will be extended to cover hedgerows. 