BIALOWIEZA, Poland (Reuters) - Environmental campaigners chained themselves to logging equipment in Poland’s ancient Bialowieza Forest on Wednesday in protest against the government-backed felling of trees in the UNESCO World Heritage site that straddles the Belarus border.

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Poland’s conservative government says the forest, which includes tracts of Europe’s last primeval woodland, is under attack from beetles and needs to be protected through increased logging. It has tripled the quota of wood to be harvested.

However, activists say some of the trees are being cut down in protected areas, threatening the local ecosystem, and accuse the government of sacrificing the forest for profits.

“Foresters have crossed a red line, they are devastating Poland’s biggest natural treasure for the sake of ad hoc profits. We will not be looking on passively,” said Robert Cyglicki from Greenpeace Polska.

The European Commission, the European Union’s executive arm, asked Poland in April to explain its decision and threatened legal action if it received no satisfactory reply within a month.

According to Greenpeace, loggers have now moved into the oldest parts of the forest and the logging has entered a “decisive phase”.

A spokesman at the environment ministry said the logging in Bialowieza Forest was designed to protect local species of wildlife and was in line with EU law.

Poland will reply to the Commission “in accordance with any procedures and laws”, the spokesman added.

Environment Minister Jan Szyszko last ran into conflict with Greenpeace a decade ago when he was also minister and promoted the construction of a motorway in the Rospuda Valley, a nesting location for rare birds in the north-east of Poland.

Campaigners set up camp then in the valley in the middle of a freezing winter, chaining themselves to trees in what became a symbol of the reawakening of civil disobedience in Poland after the collapse of communism. The Rospuda project was eventually abandoned.