Millions of conifers and other non-native trees are to be felled in the next 20 years to regenerate indigenous trees in England's woodland.
England's ancient woodlands have been threatened by foreign species
Oak, ash and beech would be encouraged to naturally seed and regenerate, said Forestry Minister Jim Knight, and Lord Clark, of the Forestry Commission.
Shading from conifers and over-grazing by livestock had taken their toll on ancient and native woodland, they said.
Lord Clark said woodlands were "jewels in the crown" and needed to be saved.
'Diverse and beautiful'
England's woodlands - which are often small and fragmented - are also vulnerable to climate change, pollution from farming, poor management and neglect, or loss to housing development.
The shake-up policy, called Keepers of Time: A Statement of Policy for England's Ancient and Native Woodland, will see more wooded areas created over the next two decades.
Some of these will be aimed at buffering or linking existing woods.
Ancient woodlands that were converted to plantations in the last century will undergo a major programme of tree felling and thinning.
Mr Knight said England's "diverse and beautiful landscapes" were justly famous the world over.
"Our ancient woods are quintessential features of these much loved landscapes, irreplaceable, living historic monuments, which inspire us and provide us with a sense of place and history," he said.
"This policy statement rightly celebrates the importance of our ancient and native woodlands and sets out the mechanisms by which they can be conserved and enhanced over the coming years."
Lord Clark, chairman of the Forestry Commission, said: "It is now time to significantly raise the profile and importance of ancient woodland by placing it at the heart of our policies on woodlands and forestry.
"Our ancient and semi-natural woodlands are the jewels in the crown of English forestry, and protecting and enhancing them will now be a high priority.
Ancient woods categorised by existence since at least 1600
England had lost about 95% of its ancient woodland by 1919
Havens for rare flowers, ferns, insects and mosses
15% to be found in Sites of Special Scientific interest
"Since the 1980s, our understanding of woodland has increased, new issues have arisen and many of the pressures on the resource have changed."
Native woods aid flood management and help regulate air and water quality. They also contain a wealth of historic features and important wildlife.