The chirp of cicadas ripples through the pine forest, carried along on the same breeze as the scent of lavender and wild thyme -- with nearly no trace of man.

The Grand Barry nature reserve in France's southeastern corner is undertaking one of Europe's largest experiments in rewilding.

At a time when reforestation projects -- planting new trees -- are growing in popularity, rewilding aims to let nature do the work by simply leaving ecosystems alone to recover, free from human influence.

According to the United Nation's biodiversity panel IPBES, at least three-quarters of all land on Earth has been degraded by human activity.

As humankind's insatiable demand for food and materials expands, more than one million species of wild animals and plants are at risk of extinction, many within decades, the UN says.

Inspired by similar movements in the United States, the Grand Barry project is overseen by the Association for the Protection of Wild Animals (ASPAS) and aims to give the forest some breathing space.

"On Earth, there are hardly any places which have not been influenced by humans, one way or the other," says Zoltan Kun, from the Frankfurt Zoological Society.

The situation is particularly acute in Europe, where a relative lack of space and large population centres mean areas of untouched nature are increasingly hard to find.

Kun says that the goal of rewilding is to create "ecosystems that can work without human intervention".

This means no tree-planting, no forestry clearance, and no or very little species reintroduction. Just standing back, and letting nature do its thing.

The process starts from the bottom of the food chain: allowing the populations of insects and small creatures to grow again will, in turn, increase the numbers of herbivores, carnivores and birds of prey within the forest.

"In most cases you just need to allow these species to extend naturally," says Henrique Miguel Pereira, IPBES's head of biodiversity conservation.

"(It's about) promoting the connectivity of ecosystems -- if you have populations of wolves in different areas, for example, they can expand if they are connected."

One of Europe's biggest experiments in rewilding is taking place at the Grand Barry nature reserve in southeast France
One of Europe's biggest experiments in rewilding is taking place at the Grand Barry nature reserve in southeast France AFP / PHILIPPE DESMAZES

This involves everything from removing small dams on rivers, to identifying and creating safe passages for wildlife to cross over or under roads.

The wooded massif of Grand Barry, spread across 100 hectares (247 acres) of France's Drome region, is shot through with a kilometres-long rocky ridge.

The forest floor all around rustles to the sound of chamois -- think deer crossed with antelope -- red deer, stoats, badgers, reptiles, not to mention countless species of plants and flowers.

In the sky above, a golden eagle darts through the air like a fighter jet, sharing flight paths with the peregrine falcon and the European hawk.

"It's just an area of pretty normal nature, but there are some nuggets," says Clement Roche, coordinator of ASPAS reserve.

Golden eagles -- once abundant in Europe -- now number only a few thousand pairs across the continent.

The area is highly protected -- banned activities include fishing, hunting, logging, farming, large gatherings and the use of motor vehicles.

Such safeguards put the reserve on a par with the highest protected status granted by the International Union for Conservation of Nature's (IUCN) criteria -- higher than that of national park.

"We let people hike here on the marked paths," says Roche, gesturing to signposts marked discreetly among the trees.

"People can pass through without leaving a trace."

In reality, just a few dozen hikers visit the reserve annually, a figure kept down thanks to its deliberately low-key communication strategy.

Flora here is left to its own devices.

Not everyone is convinced about the benefits of rewilding --  leaving ecosystems alone to recover, free from human influence
Not everyone is convinced about the benefits of rewilding -- leaving ecosystems alone to recover, free from human influence AFP / PHILIPPE DESMAZES

"When a tree falls, we leave it," says Roche, pointing to a toppled trunk that itself will become teeming with plant and animal life as it decomposes.

For Madline Rubin, director of ASPAS, the Grand Barry project is about "recreating the primary forests of tomorrow."

As well as benefiting local biodiversity, rewilding can play a key role in the fight against climate change.

As global warming changes the climate, scientists have little clue as to which species of tree will adapt the best.

Rewilding is a way of maximising those odds, according to Gilles Raye, a natural sciences professor.

"It's better to leave them alone and see which species holds up the best," he tells AFP.

"When you select specific ones, it's a bit like a poker game."

But not everyone is convinced about the benefits of rewilding.

In France, for example, there is growing opposition to rewilding among farmers and local officials, who argue that the reintroduction of wild predators such as wolves, bears and foxes threatens livestock.

"If man doesn't take care of the forest, it suffocates," said Alain Jeune, a local mayor, who opposes the ASPAS project.

Remi Gandy, president of the Drome hunting federation, said that rewilding poses a risk to "traditional economic and recreational activities", such as fishing and shooting.

Although he's not against the idea in theory, he argues it would take "thousands of hectares" to achieve meaningful results.

In another of its reserves near the Rhone river, ASPAS says signs forbidding hunting have been torn down and placed next to shotgun cartridges on the ground.

Yet, rewilding supporters are undeterred.

"The idea of many people in Europe is that nature needs people, or nature needs management," says Pereira.

"It's nonsense because biodiversity has been here before humans and will be here after humans disappear."

Kun is more succinct on the need of allowing nature its own space.

"We are not God," he says.

Although there are plenty of national parks with protective measures in place, France still has only a handful of reserves where human influence is minimal.

For Frans Schepers, managing director at Rewilding Europe, other reserves should consider rewilding, not just from an ecological but also an economic point of view.

His organisation has eight such projects in countries including Portugal, Romania and Sweden, and it assists locals with start-up loans and marketing.

"Many of those regions suffer from rural depopulation, a lack of entrepreneurial attitude," says Schepers.

So any area interested in rewilding should consider how it can help create a "new identity and pride for that region", he adds.