Information on Forest Science and Technology Number 6 2001

Summaries of papers in the bulletin; for more information contact

Bamboo resources in Vietnam

(Nguyen Tu Uong)

Bamboos constitute a very abundant and valuable plant resource. They are capable of regeneration and rehabilitation but they need good management. In the recent past many activities have contributed to the maintenance and development of bamboo resources in Vietnam.

Some rare and precious bamboo species in Vietnam

(Nguyen Hoang Nghia)

Vietnam has a large number (about 100) of bamboo species of which nine species are considered as economically valuable and some of them are very rare. These species have been widely exploited and their genetic resources are seriously depleted. Some species, such as Chimonobambusa quadrangularis (Fenzi) Makino, Phyllostachys nigra (Lodd.) Munro and P. bambusoides Sieb et Zucc. Var. aucro Makino are in danger of extinction. Sustainable use and effective conservation measures are needed to save and develop these bamboo resources.

Research on introduction of Phyllostachys pubescens in Hoa Binh province from Cao Bang province

(Dinh Van Tu)

Phyllostachys pubescens is widely planted and adaptable to growing conditions in some mountainous regions of Cao Bang, Bac Kan and Thai Nguyen provinces. This research shows that the introduction of Phyllostachys pubescens in Hoa Binh from Cao Bang is feasible and should be carried out. Due to the high value of Phyllostachys pubescens, more long-term and comprehensive research is needed.

Regeneration — ensuring exploitation and use of Bambusa procera as raw material for paper

(Hua Vinh Tung)

Research has been conducted in natural Bambusa procera forest (forest subdivision 200) managed by North Lam Ha (Lam Dong province) Protection Forest Management Board on suitable silvicultural measures for exploitation of Bambusa procera forest to develop stable forest structure and high productivity. The author points out that 50—75% of the culms in the forest stand can be harvested. However less than 10% of the medium-sized culms can be harvested. The paper also discusses laboratory research, the physical and mechanical properties of raw material as well as processing technology, pilot production and calculation of production costs.

Dendrocalamus membranaceus propagation by branch layering

(Le Quang Lien)

Dendrocalamus membranaceus is a species that can be propagated by branch layering. In a mother plant, only 11% of the branches have aerial roots. Inserting branched culm sections (6-8 months old) with aerial roots into the ground will lead to rooting in more than 90% of branches.

Layering of branches with aerial roots will also give rooting in more than 90% of branches This is a suitable method to make full use of the branches lower in the culm for planting stock.

The ordinary method of using a ball of earth (without nylon sheet wrapping) can be used only for branches that have no aerial roots. The method of using nylon sheet to wrap the ball of earth and mud can be used for layering both types of branch, with and without aerial roots.

When the layering branch has produced roots, further raising and tending in 4-6 months is needed to meet planting stock standard.

Research on bamboo planting technique for bamboo shoot production

(Le Quang Lien and Nguyen Danh Minh)

Research was conducted with two bamboo species: Dendrocalamus sp. and Dendrocalamus membranaceus.

Propagation of these two species can be done by branch layering with nylon wrapping. A planting hole with size 1 m x 1 m x 0.5 m gives twice the productivity compared to planting with a normal sized hole.

Fertilizer application: N 2.9 kg; P 2 kg; K 2 kg of decomposed farmyard manure, 22.5 kg/clump/year, divided into six applications.

The tool for culm harvesting must be sharp, the shoots are cut close to the rhizome surface and the height of the harvested shoots is 2-30 cm.

Research on the use of 3-layered pressed bamboo mat as a substitute for wooden board in the houses of people in mountainous regions of North Vietnam

(Nguyen Manh Hoat, Tran Cong, Tran Huu Thanh and Nguyen Nhat Chieu)

As a result of research, a new type of equipment line and technology suitable for production of a 3-layered bamboo mat (7, 10 and 12 mm thickness) has been developed using wall surface, house partition wall and floor as substitutes for wooden boards and ordinary bamboo mats in households of people in mountainous regions of North Vietnam.

Treatment technique for bamboo preservation by sap-displacement method

(Nguyen Thi Bich Ngoc)

In Vietnam, there is a great demand for bamboo for construction. To increase the length of service and the efficiency of use of this resource, research on the method of sap displacement for bamboo preservation has been continued, making full use of the hollow bamboo culm to hold the preservative. Details to be studied are preservative impregnation capability and the necessary moisture threshold of bamboo for effective treatment. An improved method of sap displacement preservative impregnation by Vietnam is suitable for preservation of bamboo used in widely distributed households.

Characteristics of soil under bamboo plantation and effect of planting systems on bamboo performance

(Nguyen Ngoc Binh)

Dendrocalamus membranaceus forest is a type of economic forest which generates an income early and gives a quite high, regular annual income. At the same time it is a forest type which has a positive influence on soil and water conservation.

Dendrocalamus membranaceus is a tropical forest plant species which has a high demand for moisture and mineral nutrients, especially N. Therefore, the area for Dendrocalamus membranaceus plantation establishment must have good soil which is porous (porosity > 55%), heavy texture, rich in clay particles, high water permeability, good water retention, sufficient water available almost all year round for plant growth but no water-logging in the rainy season. The soil reaction should be acidic or slightly acidic (pH H2O 5—6.5); high humus content of surface soil layer (>4.5%); high total N content (>0.25%); and high soluble K2 O content (>10 mg/100g)

To raise the environmental protection effort and economic efficiency of Dendrocalamus membranaceus forest, especially to ensure sustainable forest management, a mixed Dendrocalamus membranaceus plantation must be established with leguminous tree species capable of fixing N and establishing in an agroforestry system.

Dendrocalamus sp.

(Nguyen Tu Uong)

Dendrocalamus sp. is a large bamboo species, thornless, with big leaves, planted for its culm and leaves. Planting Dendrocalamus sp. in a scattered planting system is recommended for people in the mid-region of North Vietnam. If concentrated planting is done, Dendrocalamus sp. must be mixed with tree species. Expansion of Dendrocalamus sp. planting will contribute to raw material supply for the production of paper and export commodities.

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