While observing satellite images captured by a forest management system using remote sensing technology last month, Le Chien, a technician at the ranger station of two districts, Ham Tan and La Gi, detected "abnormal signs" on an area of the May Tao Mountain in the former.

This is a remote area with a challenging terrain that is managed by a national shooting range based in Ba Ria-Vung Tau Province, which borders Binh Thuan.

The ranger station informed the shooting range, local police, and border guard to form a team to inspect the area based on the images.

"On arrival at the coordinates shown on the system, we saw exactly what we had predicted from the satellite image," said Chien.

After a day of trekking, the team discovered that 3,200 square meters of the forest had been destroyed to create space for growing cannabis. In the cleared area were around 470 cannabis plants 40-60 centimeters tall.

The rangers even found an irrigation system directing water from a stream nearby to the cannabis garden.

No information was immediately available on those responsible for the deforestation and cannabis cultivation.

Cannabis is on the list of narcotics forbidden in Vietnam. Those growing cannabis on a small scale can be fined VND2-5 million ($86 - 215). Farmers found cultivating 500 to 3,000 plants could face jail terms of six months to three years, while those working on bigger scale could spend up to seven years in jail.

"If it weren't for the remote sensing images, it would have been difficult to detect such a major and remote deforestation site," said Nguyen Dang Hieu, head of the forest station.

The system used is a forest motorized system that applies the Sentinel satellite imagery technique and the Geographic Information Systems, Hieu said.

Costing VND3 billion ($130,000), it was put into use by the provincial Department of Agriculture and Rural Development at the beginning of this year.

The system automatically updates images twice a month, showing the exact coordinates of places where it has detected changes in the forest. It also issues warnings when detecting unusual activity.

In the past five months, it has sent more than 1,000 warnings that have led to rangers finding forest fires, deforestation and encroachment by local people.

Binh Thuan Province has more than 334,400 hectares of forest area, comprising of 288,700 hectares of natural forests and 47,700 hectares of planted forests.