The logging was detected almost a month ago in the park that straddles the three districts of Con Cuong, Tuong Duong and Anh Son in Nghe An Province.

The fallen trees with diameters ranging from 25 to 100 centimeters each were found lying in five different zones covering almost 10,000 hectares (24,700 acres) of the park in Con Cuong.

The provincial team of rangers found the trees chopped at their roots. Three of them had been cut into timber measuring 5.3 cubic meters in total.

Police in Con Cuong District have been directed to coordinate with relevant agencies to investigate the case and find the illegal loggers.

"The Pu Mat National Park is the first agency that should take responsibility for this," said Nguyen Van Thao, the district’s deputy chairman.

The park’s director, Tran Xuan Cuong, said it was spread over 94,700 hectares with just 77 officials in charge, presenting many difficulties in managing and protecting it.

"It is possible that locals had cut down those trees to get the orchids growing there," he said, adding that the park has requested rangers directly managing the zones where the logging took place to submit reports.

Pu Mat is home to 2,500 flora and over 1,000 fauna species.

The penalty for illegal logging in reserve forests in Vietnam's Penal Code is between seven and 15 years in jail