With ash dieback disease being headline news tree management is once again a real issue. Some commentators predict landscape impacts far greater than for Dutch Elm Disease.
Trees can obviously be protected by a Tree Preservation Order (TPO) which makes it a criminal offence to remove or damage the tree. In 2012, the scope of the exceptions to TPO controls was narrowed so that cutting down a tree subject to a TPO is not permitted simply because it is dying or damaged.
Whilst a dead tree or dead branches can be removed, there has to be some nuisance or immediate risk of serious harm before a TPO tree can be cut down without obtaining express consent.
Conservation areas contain similar controls, such that prior notification to the council is required before any works are carried out to trees in the area.
It seems unlikely that a council would prevent requests to remove genuinely diseased trees under either system. Whether pre-emptive removal would be tolerated is a different question. The pressure to retain as many ashes as possible, and the hope that some trees may prove to have a measure of immunity may lead to ashes being an emotive subject for years to come.