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On 23 July 2018, National Office of Intellectual Property issued Decision no. 2416/QĐ-SHTT on granting Geographical indication registration certificate No. 00068 for the famous “Cao Bằng” tortoise-shell bamboo and tortoise-shell bamboo mat. Cao Bằng’s Department of Science and Technology is the organization in charge of managing this GI. 

Cao Bằng tortoise-shell bamboo (scientific name: Phyllostachys pubescens Mazel ex H.de Lehaie) are planted into forests in the province. Cao Bằng locals speculate that tortoise-shell bamboo originates from China, immigrated by the Dao ethnics and spread thanks to their nomadic lifestyle. Nowadays, tortoise-shell bamboo is popular in Cao Bằng, Lạng Sơn, Bắc Kạn, Thái Nguyên, Quảng Ninh, etc. on the altitude of over 800 meter, where the Dao, Mèo, Tày, Nùng ethnics reside. Cao Bằng tortoise-shell bamboo has long become a familiar with the locals as their symbol. It not only possesses economic value, but also helps protecting the environment, increasing the forest coverage, preserving the soil and water resources, and developing the bio-diversity of local plants. It also holds a special place in the culture of the community.  

  

  

Cao Bằng tortoise-shell bamboo and mats made from it are reputable products, well-known to the consumers with their distinctive quality. Cao Bằng tortoise-shell bamboo grows straight, the diameter is consistent, the culms are not clearly visible, and the culm nodes are bump lines. The colour of the skin is lime to deep green. Average length of nodes is 19.4cm to 25.5cm, root nodes’ is 8.5cm to 15.5cm. The thickness of stem wall averages at 1.94cm to 2.53cm. Cao Bằng tortoise-shell bamboo has the hardness of 2.9 to 3.1 (HBS), ductility of 2,465 to 2,758 (Mpa), elasticity of 1,601 to 1,905 (Mpa), fiber content is from 78.35 to 83.45 (%), water content is from 28.30 to 34.78 (%), total ash content is from 1.07 to 1.89 (%), Lignin content is from 30.40 to 33.54  (%),Polysacharid content is from 60.05 to 68.52 (%), Cellulose content is from 40.31 to 45.32 (%). Tortoise-shell bamboo mats are made 100% from natural Cao Bằng tortoise-shell bamboo. Cao Bằng tortoise-shell bamboo has consistent, thin, long and whole-outer layer laths. The mats are made by a modern production line, therefore their strips are straight, small, flat, smooth, have better appearance and are lighter than square-eye bamboo mats. The mats are pest-free, no moldy nor other strange smell, the percentage of defective laths is no more than 0.5%. The upper face of the mat has a shiny, light yellow-brown colour. The lower face has a white-yellowish colour. Bamboo mats are weaved by six yellow-brown D3-250 threads per line, with 5cm distancing. The nylon edges as the width of 40 ± 3 mm and the corners are rounded. 

  

  

Cao Bằng tortoise-shell bamboo and mats made from it are reputable products and are favoured by the consumers for its distinctive traits. These traits are thanks to the heat, rainfall, hour of sunlight, and wind speed distribution throughout the year of the geographical area, directly affects the development of Cao Bằng tortoise-shell bamboo and especially the cultivation techniques of the local ethnics. 

  

The geographical area consists of the communes of Bắc Hợp, Ca Thành, Hoa Thám, Hưng Đạo, Lang Môn, Mai Long, Minh Tâm, Minh Thanh, Phan Thanh, Quang Thành, Tam Kim, Thái Học, Thành Công, Thể Dục, Triệu Nguyên, Vũ Nông, Yên Lạc, and the towns of Nguyên Bình and Tĩnh Túc of Nguyên Bình district; communes of Cô Ba, Đình Phùng, Hồng An, Hồng Trị, Hưng Đạo, Hưng Thịnh, Huy Giáp, Khánh Xuân, Kim Cúc, Phan Thanh, Sơn Lập, Sơn Lộ, Thượng Hà, Xuân Trường of Bảo Lạc district; communes of Vĩnh Phong, Vĩnh Quang, Thái Sơn, Thái Học, Yên Thổ, Mông Ân of Bảo Lâm district; communes of Cần Nông, Bình Lãng, Thanh Long, Lương Can, Yên Sơn, Đa Thông, Lương Thông, Cần Yên, Vị Quang, Ngọc Động of Thông Nông district; communes of Bạch Đằng, Bình Dương, Bình Long, Công Trừng,  Đại Tiến,  Dân Chủ,  Đức Long,  Đức Xuân,  Hà Trì,  Hoàng Tung,  Hồng Việt,  Lê Chung,  Nam Tuấn,  Ngũ Lão,  Nguyễn Huệ,  Quang Trung,  Trương Lương of Hòa An district, Cao Bằng province. This area has a slopey terrain, with the inclination varies between 10 - 30^o, declining from North to South and from West to East. Average altitude is 300 - 1,500 mét. Situated within an region of tropical monsoon climate, this area has an average rainfall 1,200 - 2,000mm annually, distributed evenly throughout the year. The annual average temperature is 19 - 22^oC, with the lowest is in February and March, which is the season for bamboo shoot growth. Total hours of sunlight per year are 1,382 – 1,583 hours. May, when the bamboo grows rapidly, is the month with the most sunlight hours, therefore this is a favourable condition for the growth and development of bamboo. The annual average humidity is 84 - 85%. High wind speed results in the elasticity of Cao Bằng tortoise-shell bamboo. The soil here has light to medium mechanical property, the surface layer is loose and soft. The soil has grain texture, and the layers are not clearly separated. The depth of the soil is usually 80 - 100cm and may 130cm at some places. The A layer has grey, grey-black or black colour, and the B layer has grey-brown colour, mixed with 4 - 10% of rock. pHH²O value is 4.4 – 4.6. 

Aside from the topography, soil and climate conditions resulting in such peculiarity, the healthy, stable development and high survival rate of the bamboo are thanks to the accumulated experiences of the local farmers (such as planting bamboo body underground, wholly uprooting the mature bamboo). The season for nurturing newly planted bamboo is from October to December when the humidity is relatively high, and the rainfall is low. Stable temperature is also crucial to the quality of the bamboo. During the tending of the bamboo, regularly clearing the bushes around the root helps the development of bamboo shoots and underground body. Suitable pest control techniques are also applied. Only bamboos that are over 4 years old are cultivated. In the production of tortoise-shell bamboo mats, Cao Bằng locals don’t make square-eye mats like other bamboo mats, but instead make mats with toothpick-like threads made from whole bamboo culms of which length is equal to the mats’ width. Tortoise-shell bamboo mats are made by modern production line, therefore their strips are straight, small, flat, smooth, has better appearance and durability, and are thinner and lighter than square-eye bamboo. When holding by hand, the mats are not offset as the back surface are pressed with non-absorbing cotton cloth using high pressure heat treating machine, making sure the mats are consistently flat. 

All of the factors above, combining with the peculiar and favourable natural condition, have resulted in the highly elastic, shiny and durable of Cao Bằng tortoise-shell bamboo. 

  

Geographical Indication and International Trademark Division