But officials admitted that ash dieback will not be “possible to eradicate” after scientists found the disease had spread to Britain's mature trees.
With it threatening 80 million trees in Britain, the number of confirmed cases has risen from 115 sites to 129, including 64 cases in woodland, and is expected to spread even further.
Today, Owen Paterson, the Environment Secretary, announced an “action plan” to tackle the disease after chairing the government’s emergency committee Cobra, usually only convened for terrorist or other national security emergencies.
Mr Paterson admitted the scientific advice had concluded that would not be “possible to eradicate this disease now that we have discovered it in mature trees” although he insisted it would not mean the complete death of ash.
There are fears that Britain's ash trees face a similar fate to its elms, which were destroyed by Dutch elm disease in the 1970s.
Among the immediate measures announced today included destroying “newly-planted diseased trees” and those found to be dying in nurseries because young specimens “succumb quickly” to the disease.
But in promising a "radical" rethink, Mr Paterson ruled out cutting down or burning mature ash trees to stop the disease.
They were too “valuable” to Britain’s wildlife, mature trees take a significant amount of time to die and old ash will provide valuable evidence for scientists to study to potentially find “genetic strains that might be resistant to the disease”.
There is no cure for ash dieback but some trees have already shown resistance.
Research into resistance will concentrate on identifying the gene that makes this possible and breeding it into future stock. Hybrids with foreign species from countries such as Japan may also make the tree resistant.
The decision comes after experts said specimens should be allowed to live as they are still good for wildlife and can be used for fuel.
Once a tree has ash dieback there is little that can be done and it could take up to ten years to die.
The action plan will also concentrate on research, public awareness and practical measures to stop the spread of the disease.
Research will look at how to better detect the disease so that experts can advise members of the public on how to stop it.
Practical action is based around moving leaf litter. Already ‘lateral flow’ kits, much like a pregnancy test are used to detect other diseases in trees like sudden oak death.
A tissue sample from a leaf is mixed in with a solution. The tester kit is then dipped into the liquid and a signal such as a blue bar shows if the result is positive.
“The scientific advice is that it won’t be possible to eradicate this disease now that we have discovered it in mature trees in Great Britain,” Mr Paterson said.
“However, that does not necessarily mean the end of the British ash.
“If we can slow its spread and minimise its impact, we will gain time to find those trees with genetic resistance to the disease and to restructure our woodlands to make them more resilient.
“The groups that put such a lot of effort into looking after our wildlife and our countryside will play a major role in minimising the impact of Chalara and so will the general public, especially when it comes to spotting other areas where the disease has taken hold.”
He added: “Our plans have been developed through bringing together Britain’s top experts and listening seriously to their advice.
“We now have a window of opportunity for action because the disease only spreads in the summer.”
Campaigners broadly welcomed the plans, but questions remained over where the new funding would come from.
The National Trust also said it was surprised the Government believed it will not be possible to eradicate the disease.
Dr Simon Pryor, director of natural environment at the Trust, said: "Given our limited understanding of this disease in this country, we believe we should keep an open mind as to whether it may be possible to eradicate it, or at least contain it within the core area in the east.
"Even if we only delay the spread of the disease this will buy us valuable time to establish the next generation of trees and also investigate other means of increasing resistance of mature trees.
"This is a major new national disaster for our countryside and it will require new resources to tackle it effectively."
Martin Harper, RSPB Conservation Director, said the plans were a "vital part of stopping the spread of this disease".
"We are pleased that protecting this wildlife has been enshrined in the Government’s approach to tackling ash dieback," he said.
“However, it is essential that at a time when budgets are already stretched we do not divert resources away from other vital environmental services provided by Government agencies."
Sue Holden, the Woodland Trust chief executive, added: "We support Defra's response advising that no mature ash trees should currently be felled.
"This underlines widespread concerns that rapid and ill-considered action in our mature and ancient woods could do more harm than good.
"We do not want to remove small populations of resistant ash that may hold the key to the survival of the species across the country."
The disease, also known as chalara fraxinea, is thought to have come over from Continental Europe on the wind and could have been there for years. It also spread into nurseries via imports this summer.
The disease originated in Japan and was then imported into Eastern Europe.
In Denmark it has infected 90 per cent of trees and experts say there is no sign of a cure. In fact experts say specimens should be allowed to live as they are still good for wildlife and can be used for fuel.
Ash dieback spreads during June to October when fungus in leaf litter are releasing spores. The UK imports around 500,000 ash trees every year.
The Government has banned import of ash and movement of trees around the country.
Talks are ongoing with Europe on tightening up the laws around tree imports, including introducing ‘plant passports’ and quarantine.