Rhamnoneuron Facts : Amasix Asia Group Ltd, Handicraft of Vietnam

Vietnamese name: Do giay

Other names: Do, Vo do

Scientific name: Rhamnoneuron balansae Gilg

Family: Thymeleaceae

1/ Morphological description:

R. balansae is a wooden bush species, average height 3.5- 4.0m, usually multi-stemed due to regenerated shoots. Average diameter of 4 year old tree from shoot is 3.5- 4 cm.

Bark smooth with fine cracks along the stem, pale or greyish brown in colour. Bark of 3-4 year old tree is 3.0-3.5 mm thick on the average, inner bark ivory white with soft and coriacuous fibres. Cellulose content is 45-50% on the average depending on tree age. Ratio of air dried and fresh weight of bark is 1/3.5-1/4.0.

R. balansae has single leaves, alternate, leaf blade ovule, tip rounded, base obtuse or lanceolate, margin entire, 8-10 cm long, 2.5-5.5cm wide, leaf blade thickness 0.38-0.42mm (� 0.02-0.03), venules 14-18 pairs, opposite through midrib. Petiole small, red in colour, 4-5mm long. Bud pale green, tomentose, silvery in colour.

Inflorescence racemose, apical, numerous clusters, each with 3-4 flowers. Flower bud globose, bract white or pinkish, purplish, thick tomentum. Calyx adnate, cup-shape tappering at both ends, 4 short lobes. Stamens arranged in two rows. Anther 2-celled lengthwise splitting, upper ovary 1-celled, 1 ovule.

Fruit: No splitting when ripe, apical clusters each with 3-4 fruit, closely adnate at a short pedicel. Fruit 1.0-1.2cm long cross section in the middle of the fruit is square shaped due to four small ridges, width 3-4 mm. Each fruit has one rhomboid seed, 0.5-0.8 cm long; 3-4mm wide, tightly wrapped in a porous, soft but coriaceous coat. Thus the seed can hardly come out of this coat and absorb water. Typical feature of the fruit and seed is small, light with some basic indices as follows:

� Fruit purity: 79.7%

� Number of fruit per 100g: 3,245 fruit

� Ratio of fruit containg seed: 80-90%

� Weight of 1,000 seed: 8.5g

� Average number of seed per kg: 117,000-120,000

2/ Ecological characteristics:

In Vietnam R. balansae is distributed from 21^o06 to 22^o09 N-latitude at 50-400m a.s.l. R. balansae is distributed and most concentrately planted in an arched area of mid-land low hills from North East of North Vietnam through Mid region of North Vietnam, westernmost to part of low area of North West of North Vietnam. R. balansae prefers tropical monsoon moist climate, high mean annual rainfall (1,600-3,800mm), average air humidity rather high (82-86%), total hours of sunshine 1,520-1,620.

R. balansae grows well in soil types generated from metamorphic rocks such as mica schist, crystal schist, gneiss and acidic alluvial rock, reddish yellow or yellowish red feralit, thick soil layer, texture from loam to medium clay, pH from acidic to slightly acidic.

R. balansae grows mixed with other species in rehabilitating broad leaved forest as Livistona sabribus forest mixed with Ormosia balansae, Engelhardia chryrolepis, Canarium album, Prunus arborea or it grows in pure patches in home garden. Besides R. balansae is also planted in mixed rows or bands with a number species yielding paper raw material such as Styrax tonkinensis, Manglietia glauca and attains good growth.

R. balansae is capable of regeneration from seed at forest margin or suitable open places around the base of mother tree. Specially its regeneration from shoots is very strong at almost all ages. Taking advantage of these biological characteristics one can do the planting with stumps and practise management with many coppice rotations in many years.

Flowering of R. balansae is from October to December, fruit is ripe in large number in late March-early April in short period of time and then all fall. Thus, time of fruit collecting must be strictly monitored, the best time is usually in 3^rd day of 3^rd month of lunar year.

3/ Uses

Bark of R. balansae has cellulose content from 40 to 50% (depending on tree age), fibre length 6-7mm, width 10 m, the length is 600 times the width thus the fibre has high mechanical strength.

Pulpwood of R. balansae has a cellulose content 92-93%, copper index is low, 1.13%. Pulpwood to produce paper of high quality must have a cellulose content � 90% and copper content � 1.5%. Thus bark of R. balansae is very suitable for production of high quality paper (durability upto 500 years). In experiences of the people in many regions of North Vietnam, bark of R. balansae is used to produce tissue paper, paper for writing chinese characters, soft and coriaceous paper such as core of stencil, paper articles for worship, table paper, printing paper for folk paintings (Dong Ho paintings). More specially, honour certificates issued by feudal dynasties from XV century in Vietnam were written on paper made of R. balansae bark and they are now stored in many communal houses, pagodas or in national archives. Besides leaves, flower and roots of R. balansae are also used as medicine by the people in mountainous regions. Wood of the stem is used to produce paper pulp or firewood. At present many private and cooperative production units in Bac Ninh and Bac Giang still maintain and develop paper production from R. balansae bark with traditional handicraft method (Phong Khe-Dong Khe, Bac Ninh).

Practically demand for paper keeps increasing not only in quantity, quality but also in diversified categories. Apart from paper categories of common use there is still urgent demand for paper of high quality used for records, restoration of documents, national cultural and historical printed matters that must be kept for long time. With its mechanical physical properties and basic indices of R. balansae bark that have been studied and tested, it is shown that R. balansae pulp are entirely suitable for high grade paper production.

4/ Evaluation of R. balansae plantation

From a very long time the people in many regions of North Vietnam have exploited R. balansae bark in natural forest to make paper for common use. The exploitation has been most concentrated in the provinces of Mid-region of North Vietnam, North East of North Vietnam and part of North West of North Vietnam. Besides, R. balansae planting has also been extended by seed sowing in home gardens, home forests, around hill foot or at hill sides, 1-2 year after slash-and-burn cultivation by people in the mountainous region on small scale in scattered plots (Dai Tu-Thai Nguyen, Chiem Hoa-Tuyen Quang; Yen Binh, Ngoi Lao- Yen Bai, Thanh Son-Phu Tho and Kim Boi-Hoa Binh). In 1982-1985 period concentrated planting of R. balansae was done in Ngoi Lao district, Yen Bai province on hundreds of hectares. From 1986 to 1995, ecology and sowing technique of R. balansae was studied and model of R. balansae plantation has been established on tens of hectares in Tu Quan-Tuyen Quang and in Cau Hai Silvicultural Research Centre, Doan Hung, Phu Tho. The research results obtained and the existing forest plantation models will serve as a base for expanding R. ba ansae in production. Thus it can be said that at present the raw material for production of paper from R. balansae in the traditional way is mainly exploited from natural forest. As regards raw material supply, forest plantations are still few. Raw material supply has not been planned and is not stable.

Today demand for high grade paper is urgent to serve the archives and restoration of national documents. R. balansae bark is suitable for production of high grade paper but the processing technology especially the pulp moulding, still remains a problem. Spiral structure and mechanical strength of the fibres cause difficulties for pulp moulding by machine. Thus research for suitable pulp moulding technology to replace old traditional pulp moulding method and technique on small scale and with low productivity together with supplementary research on genetics, breeding for high productivity, planning and expanding the planting regions aimed at creating long term and stable raw material sources, meeting practical requirements are highly significant and necessary.