Heavy rain clatters on the windscreen of Ion Holban’s four-by-four as he shifts through the gears to make it up a steep dirt track deep in Romania’s Carpathian Mountains, a wilderness where pristine forests host bears, wolves, lynx and wildcats. Holban wants to keep it this way, which is why he has organised a 50-strong group of experts and campaigners to join him on a week-long mission to map out the vast tracts of ancient woodland before it’s too late.

“There’s pressure from logging all across Romania,” says Holban, the campaign co-ordinator of Agent Green, an anti-logging NGO. “The government is not treating the virgin forests with the respect and value that they deserve. There’s very little protection in place.”

Romania is home to more than half of Europe’s last remaining primeval forests – some 200,000 hectares of beech, spruce, fir, oak and other species – much of it in the Carpathian Mountains, which sweep in an arc across the country. But by some estimates, it is losing as much as three hectares of total forest cover an hour, including valuable virgin forests, as a result of legal and illegal logging and degradation.

The problem has grown since the fall of communism in 1989. With corruption endemic in Romania, successive governments have been unwilling or unable to put a stop to illegal logging. Foreign timber companies have also been accused of taking advantage of the lax enforcement.

The Austrian company Holzindustrie Schweighofer is Romania’s biggest exporter of wood, with annual revenues of around half a billion pounds. Much of the timber ends up in other member states of the EU, which Romania joined in 2007.

In 2015, the Environmental Investigation Agency (EIA), a US-based NGO, published a report on a two-year-long investigation that accused Schweighofer of purchasing illegally sourced wood. The company denied the claims.

Few areas are out of reach for illegal loggers. According to Greenpeace, of the 280,000 hectares of Romania’s total forest cover lost between 2000 and 2011, nearly half was located in national parks and other so-called protected areas.

“Even inside national parks, nothing is safe. There are ways in legislation to get around it,” says Holban, a well-built man, over a beer after a long day mapping the forests. “They can say they have an infestation of insects, and then they’ll inflate the issue and cut many more hectares than necessary.”

The race to save the trees has been set back this year. Environmental campaigners claim that the Social Democrat (PSD) government, which won power in December, is reversing hard-won measures designed to prevent illegal logging.

According to Agent Green and other NGOs, the government is trying to withdraw the official status of a register of virgin forests that was funded by the Royal Dutch Society for Nature Conservation in 2005. The PSD is also pushing to abandon a real-time tracing system for timber – monitored by satellites – that was initiated by the previous government and was supposed to come into full effect in April. The government has questioned the validity of the contract with the software company.

The effect of illegally logged timber on Romania’s rich biodiversity is clear. In June, Greenpeace Romania released aerial-view photos from Sadu Valley in Transylvania, in the centre of the country, where 100 hectares of state-owned forest have disappeared. The once-picturesque spruce-covered slopes now reveal barren expanses of earth scarred by fallen and dragged timber. Greenpeace called the site an ecological disaster.

“Sadu Valley is a sad example of how legal papers can cover for disastrous logging done without any respect for the law and the ecosystems,” says Valentin Salageanu, the head of forest campaigns at Greenpeace Romania. Greenpeace claims that the trees in Sadu Valley should have been selectively cut – removing fewer trees over a larger area – rather than clear-cut, which is much more damaging to the wider ecosystem. “It’s not at all an isolated incident, but a widespread practice in state and privately-owned forests,” Salageanu says.

The campaigners’ claims are backed up by official statistics. Between 2009 and 2015, illegal logging reports to local authorities increased from 30 to 96 per day. A study by Romania’s National Forest Inventory, a state body, estimated that nearly half of all the timber harvested in the country between 2008 and 2014 was illegally cut.

Enforcement efforts by the previous government appeared to be paying off, with reports of illegal logging falling to 26 per day in 2016. But according to the campaigners, these gains are now in danger.

Public anger over illegal logging is widespread. In 2015, thousands of Romanians took to the streets in 14 cities to vent their anger over the alarming rate of deforestation. The European Union has also expressed its concern. In 2015, the European Commission highlighted Romania’s weak enforcement of EU regulations on timber and threatened to take the country to court if it continued failing to meet the required standards.

Without more external pressure, it may be up to the activists to lead the campaign to protect the country’s natural heritage. Thanks to their efforts, around 10 per cent of Romania’s virgin forests won Unesco World Heritage status in July.

“We’re regarded as a nuisance for the government right now,” says Octavian Anghelescu, a campaigner who joined Holban’s camp and will spend his free time this summer with Agent Green. “In time, hopefully, we’ll have a stronger voice and we can change the situation in favour of nature. Our forests are unique in Europe. It will be a great shame if we lose them.”

As the sun sets over the 18th-century former hunting lodge in Covasna County, several campaigners leave with Holban in his Jeep for home. But in a few hours, Holban will return with more volunteers eager to help save the forests.