A 12,000-year-old German forest located near the Belgian border can be largely removed in order to turn the area into a coal strip mine, a court in western Germany has ruled.

The ruling by Cologne's administrative court will allow for the clearance of much of the Hambach forest, according to the Associated Press. The court's ruling came after environmental group BUND filed a legal complaint about energy company RWE's decision to turn the forest into a coal mine, the report added.

But because RWE owns the land, the court said there's very little it can do to stop the company from knocking down trees in the ancient forest, according to Deutsche Welle. BUND said it was known that RWE's expansion plans would have to include bulldozing the Hambach forest and should have never been approved, the report added.

The area stripped for coal mining has increased in size every year since 1978, and the forest is now just 10 percent of its original size, according to RT.com.

Activists are even angrier about the ruling because it came just days after the European Union threatened to fine Poland if it continued to cut down trees in the Bialowieza forest – a UNESCO World Heritage site – RT.com also reported. Polish officials said the trees needed to come down to prevent the further spread of a beetle that was ravaging the forest.

Much of the coal for nearby power plants comes from the 52-square-mile mine, according to the AP. The mine contains a light brown coal known as lignite, and it's one of the worst polluting forms of fossil fuel, the report added.

BUND will appeal the ruling and seek an injunction that would prevent RWE from destroying the forest, the AP also said.

"We will continue to pursue all legal and political avenues to stop this irresponsible open-pit mine and to save what remains of the Hambach forest," Dirk Jansen, a managing director with BUND, told Deutsche Welle.