Ten villages joined the Cao Bo tea production: Chat Tien, Tham Con, Ban Dang, Khuoi Luong, Thac Tang, Thac Tau, Thac Hung, Tat Khao, Tham Ve and Lung Tao. Green Bridge is encouraging those farmers to join and build a democratic cooperative which could be certified as sustainable for the region.

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These villages are situated in the north of Vietnam, in the Tay Con Linh mountains, an official protected region. This protection is necessary to ensure the prosperity and development of the tea plants. Nowadays, 645 families of tea producers, most of them, Dao people, are certified organic. This region is also well known for the Pho Nhi tea, also named Puerh tea, which means fermented tea. This naturally fermented tea is only composed with the old Shan Snow tea. It has to be organic because the pesticides and other chemicals would have stopped the development of the microorganisms, which would have make the fermentation impossible.

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Nobody knows the real production processes of the Vietnamese Puerh tea, except the locals because they share the border of Puerh, original city of the medicinal tea. The story of this tea started under the Tang dynasty (618-907) when the border was not as established as now. At that time, it was consider as a big region where minorities live together and share their expertise.