Ten per cent of the world's tree species face extinction through felling, forest fires and poor forest management, according to a warning from international conservationists in a report published yesterday.
"With 77 species already extinct, this report has now confirmed our worst nightmare," Dr Steve Howard of the World Wide Fund for Nature (WWF) said.
The World List of Threatened Trees details more than 8,753 of the world's 80,000 to 100,000 tree species as being in danger of extinction.
The 650-page report is the resulted of a three-year collaboration between the World Conservation Monitoring Centre, partly financed by the WWF, the Species Survival Commission of the World Conservation Union (IUCN), and the WWF, financed by the Dutch government.
Some 1,000 species were classed as "critically endangered", reduced to tens of specimens as a result of felling, the report claims.
"It's scary, there's no other word for it," Dr Jean-Paul Jeanrenaud, head of WWF's forest program, said in Geneva.
The report coincides with the start of a two-week meeting in Geneva of a UN Forum on forests, at which government delegations will discuss measures to slow down deforestation.
Dr Jeanrenaud called on governments to take responsibility for better forest management and tree protection. He pointed to a pledge by 22 countries, among them China and Brazil, to protect a minimum 10 per cent of their forests by the year 2000, as one example of possible action.
Among the most threatened species listed in the report are three of which only one specimen is known to remain, all due to loss of their natural habitat.
A group of four Hibiscus clayi trees in Hawaii's Nounou mountains appears to be the only remaining population of that species, the study said.
Illegal cutting of trees is at fault for the disappearance of other species such as a rare whitebeam now reduced to around 30 trees in south-west England, the study said. Eleven tree species in the UK face extinction, according to the report.
The varieties threatened in the UK are all from the Sorbus group. They include Ley's Whitebeam with only 16 individuals surviving in two sites in Breconshire. Another endangered species is Sorbus Wilmottiana, with only 20 trees clinging on in the Avon Gorge. The organisations warned that species are being eliminated that haven't yet been investigated scientifically. "We don't know the knock-on effect" of that, Dr Jeanrenaud warned.
A Dutch government delegate, Mr Tom van der Zon, warned that spectacular results shouldn't be expected from the UN forum, but was hopeful it would help improve conservation efforts.
The list includes several species with just one tree left, such as China's single remaining Carpinus Putoensis which survives fenced off at the edge of a sparse forest, the victim of deforestation.
Conservationists said most living species were dependent for their survival on trees. Dr Wendy Straham of the IUCN said: "We know that the conservation situation for plants is alarming. If we can't save these elephants of the plant world, then the prognosis for all other species which depend on trees is frightening."