On the steep, dark slopes of the Carpathian mountains, 300-year-old beech trees scrape the sky in one of Europe's last remaining virgin forests, spared from any human intervention for centuries.

These are "unique forests," home to thousands of brown bears, lynxes and wolves, "mammals nearly extinct in western and central European countries," the Royal Dutch Society for Nature Conservation notes.

But as demand for timber surges, the last great swathes of ancient forest in Europe are at risk, say green campaigners.

On Tuesday, Environment Minister Laszlo Borbely pledged to beef up protection of what he called a "treasure" of biodiversity. The move came after President Traian Basescu named the forests a vital asset for Romania's image abroad.

But turning this vow into reality may be tough in a country struggling with a creaking legal system and deep-rooted corruption at local level.

Primary or old forests, which include some of the world's most species-rich ecosystems, account for 36 percent (1.4 billion hectares, 3.46 billion acres) of the world's forest area, according to the UN Food and Agriculture Organization (FAO).

In Sinca, central Romania, the forest hosts imposing century-old indigenous 45- or 50-metre (147- to 164-feet) trees, interspersed with striplings and fallen trunks where innumerable species of insects and plant have made their home.

In Europe, these wild forests have disappeared except in Scandinavia and Eastern countries. In Romania, they are vast, even though they have shrunk from some two million hectares in the 19th century to around 250,000 hectares today, according to official figures.

"It's thanks to their inaccessibility that they have survived," Erika Stanciu, the head of the World Wide Fund for Nature's Carpathians/Forests and Protected Areas Programme told AFP.

The remoteness that protects them is being nibbled away by economic development as the former Communist country strives for prosperity.

-- Jewels at risk --

"Over 80 percent of Romania's virgin forests are not protected in any way at the moment and are at risk of being legally destroyed," the WWF said last month.

"Once virgin forests are exploited, the genetic and ecological assets that have accumulated for years in their ecosystems are irremediably lost," Victor Giurgiu, a member of the Romanian Academy, the highest scientific body in the country, said.

A petition urging the Romanian government "to take urgent and efficient protection measures" garnered some 100,000 signatures in less than a month.

Under pressure, Borbely pledged in November to finalise by the end of the year legislation putting all virgin forests under complete protection.

"No exploitation whatsoever will be allowed," he said on Tuesday, after signing a memorandum of understanding with the WWF.

Even so, the process will probably not be in place before next spring, Costel Bucur, WWF Forest Programme Coordinator, told AFP.

Private virgin forest owners will have to be compensated. The ministry and the WWF will try to persuade the European Commission to let European funds be used.

A model for compensation has already been implemented in Sinca. There, the municipality accepted to leave part of its virgin forest untouched in exchange for compensation paid by the WWF.

"The fact that after many years the minister has made a clear public commitment to protect all virgin forests is a big success to be attributed to the WWF campaign -- but we'll have to see if these measures are implemented," Gabriel Paun, the head of environmental group Agent Green, told AFP.

Another question is whether Romania has the ability -- or will -- to impose tough protective measures.

Illegal logging by private firms has been making front-page news.

Last month, Agent Green denounced a case of illegal felling in one of Romania's most famous natural parks. Some of the timber had been delivered to a lumber factory owned by Austrian company Schweighofer, the group said.

Junior environment minister Cristian Apostol said that thanks to tougher controls, seizures of illegally logged wood soared from 189,892 cubic metres (6.7 million cubic feet) in all 2010 to 134,883 cubic metres in the first six months of 2011 alone.

But connivance at local level is a problem.

"We had to bring in police officers from other regions in order to avoid complicity at local level," said Apostol.

Prosecutions, too, are long-winded affairs. Since 1990, only 0.5 percent of cases brought to justice have received a final verdict.