Without the Derung people's protection and sacrifice, the Dulong River valleys would not harbor one of the country's best preserved primitive forests, Li Haishu, director of the forestry bureau of Nujiang prefecture in Yunnan province, tells China Daily.

"As a treasure trove of biodiversity, the area is considered one of the country's last virgin lands of discovery," he says.

According to the official who has been working in nature conservation in the region for a dozen years, only about 3,000 Derung people live at the Dulongjiang township in Gongshan county, with an area of 1,900 square kilometers, of which 242,800 hectares belong to the Gaoligong Mountains National Nature Reserve.