Warsaw - The European Union asked Poland on Thursday to stop massive logging in one of Europe's last primeval forests, warning it might take the country to the European Court of Justice if it doesn't reverse course.The European Commission, the executive arm of the EU, said it had given Poland "a final warning" to stop the large-scale felling of trees in the Bialowieza Forest. The commission said Warsaw has a month to react, rather than the customary two-month deadline, due to the threat of "serious irreparable damage."Bialowieza is a last relic of an ancient forest that once stretched across the lowlands of Europe, a mossy woodland that is home to bison, storks and other animals. The forest straddles Poland and Belarus, with parts of the Polish section theoretically protected by their status as a Unesco world heritage site and a Natura 2000 site, a special status under EU law.High chance of finesPoland's government last year increased logging threefold. The previous level had been considered sustainable. So far thousands of trees, some more than 100 years old, have been cut down.Environmentalists have been alarmed by the logging and welcomed the EU's step."The Polish government is not only violating the law, it is attacking its own land and the people who want to protect it," said Agata Szafraniuk, a lawyer with ClientEarth. "If the case goes to the EU Court of Justice, it will be hugely embarrassing for the Polish government. There is also a high chance of being handed significant fines, with taxpayers footing the bill."Poland's Environment Ministry says its actions conform to European and Polish law.