Actress Dame Judi Dench has lent her support to a campaign to save an ancient Welsh woodland and avert a "national tragedy".
Dame Judi has won Bafta awards and an Oscar for her work
The remaining 352 hectares (870 acres) of Wentwood Forest, near Newport, have been put up for sale.
The Woodland Trust (Coed Cadw) has raised £500,000 of the £1.5m asking price and is hoping Dame Judi's backing will encourage more people to help.
The ancient wood is the largest left in Wales and is home to protected species.
Dame Judi, a supporter of the Woodland Trust, said: "There are over 75 species of birds and 23 species of native butterflies recorded in the area.
"Plants include the wild daffodil, wood anemone and enchanters' nightshade amongst others.
"All these characteristics are now struggling to survive. This is our last chance to protect Wentwood Forest and restore it to its former beauty.
The forest once stretched from the River Usk to the Wye Valley
"It would be a national tragedy if the characteristics of this ancient site were lost forever so please help us by offering your support or making a pledge to our public appeal."
An ancient woodland is described as land which has been continuously wooded since 1600 AD in Wales and England or 1750 AD in Scotland.
Wentwood Forest was once past of a vast woodland which stretched from the River Usk to the Wye Valley.
The Woodland Trust said most of its native broad-leaved trees were felled for timber during World War I, after which commercial forestry and the planting of conifers damaged its flora and fauna.
The organisation is concerned that the site will be bought by a commercial forestry firm if it cannot raise enough funds.