The Government has faced criticism for failing to protect woodlands as a ban on ash tree imports was introduced to try to stop a devastating disease spreading.
The ban prevents the import of ash plants, trees and seeds, and movement restrictions will stop trees from infected areas being moved elsewhere in the country, as part of efforts to stop the spread of Chalara ash dieback.
The disease was first identified in the UK in imported trees in February and has been found in nurseries and recently planted sites, including a car park and a college campus.
Last week officials confirmed it had been found in the wider countryside in East Anglia, with trees likely to have been infected as a result of spores blowing over from the continent. The discovery has increased fears that one of the country's most common native trees faces the same fate as the elm, which was devastated by Dutch elm disease in the 1970s.
The Chalara fraxinea fungus, which causes leaf loss and crown dieback and can lead to ash tree death, has wiped out up to 90% of ash trees in Denmark and is becoming widespread throughout central Europe.
Announcing the ban, Environment Secretary Owen Paterson said the disease was a serious one that demanded action to stop its spread. He said the import ban and movement restrictions came into force immediately.
Around 100,000 trees planted in the last five years have been destroyed, while the Forestry Commission said staff had been taken off other duties to survey for the disease in East Anglia, the South East and East Midlands. The ban, to curb further spread of the fungus, is being put in place before the main tree-planting season begins in mid-November.
"By working together we can protect our native trees from this devastating disease," said Mr Paterson. But shadow environment secretary Mary Creagh accused the Government of being "asleep on the job", and of funding its forest research body at a minimal level, leaving officials with no capacity to tackle tree pests and diseases.
She said the Government had cut the Forestry Commission's budget by 25%, and reduced forest research funding from £10 million to £7 million a year. "Those cuts reduced the Forestry Commission's ability to identify and tackle tree disease."
And she told MPs: "After the forest sell-off fiasco this Government has been asleep on the job with ash dieback. Like Nero, ministers fiddled, and now it is our forests that will burn."