Environment Secretary Owen Paterson says there are a range of diseases which could threaten the countryside. He says a new attitude is needed to help tackle them.
Experts say little can be done to stop the spread of 'Ash dieback' the disease threatening to devastate the UK's ash trees.
One of the UK's biggest tree growers will seek damages from the government after losing thousands of trees to ash dieback disease.
The disease threatening to wipe out the majority of Britain's ash trees may have spread - as experts say an import ban was too slow.