WARSAW, Poland (AP) — Hundreds have marched in Warsaw to protest widespread logging in Europe’s last primeval forest, a project undertaken taken by Poland’s conservative government.

The ruling Law and Justice party has allowed increased logging in the Bialowieza Forest, a vast woodland that straddles Poland and Belarus, alarming environmentalists who say it threatens a natural treasure. The forest has been designed a UNESCO World Heritage site.

The government says it’s fighting an outbreak of bark beetle, but ecologists see that as a pretext to increase timber production for profit.

Speakers at the rally Saturday organized by Greenpeace said they want the entire forest to be declared a national park to ensure its protection. Currently only the forest’s core is protected on the Polish side.

The protesters marched with signs to the Environment Ministry.