As a local planning authority, Wyre Council has an obligation under the Town and Country Planning Act 1990 to make a Tree Preservation Order (TPO) "if it is considered expedient to do so."
Usually the test for expediency is whether or not there is a clear threat to the tree such as heavy pruning or felling. Most TPOs are made in response to a planning application that would result in tree losses, but occasionally they arise for other reasons - because a feature tree in a front garden is to be removed, for example.
Wyre has policies in its local plan that reflect a desire to preserve trees in the development process, and we ask that developers and architects use the presence of important trees on sites to inform the design and layout rather than to assume the trees can be removed prior to development.
Not every tree is a suitable TPO candidate. The basis of the preservation order is usually public visual amenity, so in essence the tree should not only be a healthy one of good form but should also be visible from a public place. Young trees may be protected on the basis of future visual amenity. Unless a threat to a tree exists, most councils will not make a TPO on the precautionary principle.