Bambusa bambos (L.) Voss
Vilm. Blumengärtn. ed. 3, vol. 1: 1189 (1896).
Gramineae
2n = 70, 72
Origin and geographic distribution
B. bambos is native from India to southern China, including Thailand and Indo-China. It is also cultivated throughout the tropics, in South-East Asia especially in East Java, Singapore, Peninsular Malaysia, Thailand and the Philippines. For map click: Map510.TIF.
Uses
B. bambos is a multipurpose bamboo with a range of uses ranging from edible shoots (vegetable), leaves (forage) and seeds (famine food) to valuable culms for household uses and basic construction materials. It is often planted as wind-breaks around farms and along rivers to check floods. In rural areas the culms are used for flooring and roofing of cottages. The culms are among the best and strongest for building purposes and scaffolding, and when well seasoned they are durable. In logging areas the culms are used for floating heavy timbers. At present the culms are important raw material for paper, pulp and plywood industries. The richly and uniformly branched culms are suitable ladders. Such natural ladders may serve for more than 2 years and they are, for example, extensively used to climb tall sugar palms to tap the sweet sap from the young inflorescence. When young, the culms of B. bambos are covered with wax (up to 0.25% of the weight). This wax can be used as a base for shoe polish, cheap-grade sealing wax, carbon paper and waterproof kraft paper.
In India the leaves of B. bambos are used in the Ayurvedic system of medicines for blood purification, leucoderma and for treatment of inflammatory conditions. An infusion of the leaves is used as an eye wash and internally it is given for bronchitis, gonorrhoea and fever.
Production and international trade
The production of B. bambos culms in South and South-East Asia is considerable, but no statistics are available. Most culms are used locally, domestically and industrially, but there is some export. India is certainly the largest producer and consumer, e.g. in Maharashtra State alone, natural and planted B. bambos occupies an area of 13,000 km2 and in Karnataka State annual production is 160,000 t. In Thailand, for example, one paperpulp factory consumes over 2000 culms daily.
Properties
Fibres in the culm of B. bambos have the following dimensions: length 1.73-2.52 mm, diameter 16.34-22.0 µm, lumen diameter 4.93-7.44 µm, wall thickness 5.37-8.0 µm.
The average density of green bamboo (moisture content 104.1%) is 438 kg/m3, of air dried bamboo (moisture content 14.3%) 664 kg/m3. B. bambos seasons without much degrade. Mature culms dry rather slowly, showing very little cracking. Thick-walled pieces collapse slightly and thin-walled immature pieces may develop deformations. The following shrinkage percentages have been reported: in wall thickness for immature culms 9.6% (air dried), 12.3% (oven dried) and for mature culms 13.4% (air dried), 16.4% (oven dried); in diameter for immature culms 7.1 % (air dried), 10.5% (oven dried), for mature culms 9.9% (air dried), 13.4% (oven dried). The mechanical properties for air dried (moisture content 14.3-15.6%) and green (moisture content 104.1%) culms are respectively: modulus of elasticity 3099-12,190 N/mm2 and 2687 N/mm2, modulus of rupture 47.3-95.6 N/mm2 and 45.2 N/mm2, compression strength parallel to grain 40.3-64.9 N/mm2 and 34.0 N/mm2, shear strength 47.18 N/mm2.
The approximate chemical composition of the culm is: holocellulose 58-67%, pentosans 20%, lignin 22-30%, ash 3-5%, silica 3-4%; the solubility in cold water is 4.6%, in hot water 6%, in alcohol-benzene 1.2% and in 1% NaOH 19%. Per 100 g edible portion young shoots contain: water 87-88 g, protein 3.9-4.4 g, fat 0.5 g, carbohydrates 5.5 g, fibre 1 g, ash 1 g, Ca 20-24 mg, P 40-65 mg, Fe 0.1-0.4 mg, vitamin A 76 IU, vitamin B1 0.16 mg, vitamin B2 0.05 mg, vitamin C 0.3-0.5 mg. The energy value is about 185 kJ/100 g. Young shoots also contain 0.03% HCN (after hydrolysis of cyanogenic glucosides) which should be removed by sufficient cooking before eating.
The approximate chemical composition of the leaves on dry matter basis is: protein 19%, fibre 24%, ash 12%, N-free extract 41%; Ca 56 mg and P 170 mg per 100 g. The digestible crude protein fraction is 13.5% and the total digestible nutrient content 46.5%.
The chemical composition of the grains (caryopsis) per 100 g edible portion is approximately: water 8 g, protein 13.5 g, carbohydrates 73 g, fibre 1 g, fat 0.4 g, ash 1.7 g, Ca 87 mg, P 163 mg. The protein content is comparable to wheat and in quality it is comparable to rice. The 1000 seed weight is 11.6 g.
Description
Densely tufted, sympodial bamboo. Culm erect, up to 30 m tall and 15-18 cm in diameter, wall very thick, sometimes almost solid in upper part of culm and distal parts of branches; internodes usually 20-40 cm long, bright green; nodes slightly swollen, lower ones sometimes with aerial roots. Branches develop from all nodes, lower branches spreading, spine-like, bearing recurved spines, forming a dense, nearly impenetrable thicket in the lower part of the clump, upper leafy branches horizontal or ascending and bearing small spines, or spineless; spines usually in groups of 3. Culm sheath 15-35 cm x 18-30 cm, coriaceous, wrinkled at the top, brown hairy when young, glabrous when old, deciduous at the time the branches develop; ligule continuous with sheath top, 2 mm long, white ciliate; blade more or less reflexed, persistent, much shorter than the sheath, triangular, with a broad sloping and wrinkled base on either side (constituting the auricles), glabrous abaxially except for the brown, pilose wrinkled portion, adaxially densely dark-brown hairy. Leaf blade lanceolate to linear, 6-22 cm x 1-3 cm, glabrous, slightly glaucous beneath; ligule short, entire; auricles small, bearing a few bristles. Inflorescences at first terminating leafy branches, ultimately resulting in small clusters of pseudospikelets at the nodes of leafless branches; spikelet lanceolate, about 2 cm long when mature, consisting of 0-2 empty glumes, 3-7 fertile florets (lower ones hermaphrodite, upper ones male) and 1-3 imperfect florets. Caryopsis ellipsoidal, 4-8 mm long.
Growth and development
B. bambos readily establishes from seed. The clump reaches about 5 m height in 7 years and about 20 years are necessary to reach full growth comprising 25-50 (-100) culms. Twelve-year-old clumps are regarded as mature. Undisturbed clumps are almost impenetrable after some years because of the interlacing thorny branches.
B. bambos flowers gregariously over a region at intervals of (16-)32(-45) years. A complete flowering period of the whole clump takes as long as 3 years. Flowering is followed by profuse seeding after which the old clump dies. In bamboo areas protected from fire and grazing natural regeneration occurs without difficulty.
Other botanical information
B. bambos is related to and resembles B. blumeana J.A. and J.H. Schultes but has larger, straighter culms, more open branching, narrower smoother leaves and its culm sheaths bear very hairy blades that are gradually decurrent along each side of the top of the sheath and the decurrent parts are curled and not auricle-shaped.
The nomenclature of B. bambos is complex; many authors prefer the name B. arundinacea (Retzius) Willd., and consider Arundo bambos of Linnaeus as a 'nomen confusum'.
B. bambos is a very variable species, ranging from clumps with handsome, straight, large culms up to 27-30 m tall (tallest recorded up to 40 m) with a diameter of 15-17 cm, to clumps with almost dwarf, thick-branched, very thorny small culms up to 7 m tall. Thornless (or almost thornless) forms exist as well.
Ecology
B. bambos prefers a humid tropical climate and grows best along river valleys and in other moist conditions. It is found most abundantly in mixed moist deciduous forest, and not so commonly in mixed dry deciduous forest and in semi-evergreen forest on hills up to 1000 m altitude.
Propagation and planting
B. bambos is propagated by seed, rhizome cuttings and by tissue culture. Fresh seed germinates readily in 5-10 days after sowing, with a germination percentage of up to 80%. Seeds remain viable for about 6 months when stored at 5ºC or when stored dry in sealed containers (with CaCl2) at room temperature. Seeds stored without lowering temperature or moisture content will lose viability completely within 3 months.
Propagation by seed is most practical for large-scale plantings. Although B. bambos flowers and fruits gregariously at long intervals, every year individual clumps can be found flowering and fruiting in various regions of a country. As fruits are abundant, seed is seldom the limiting factor for propagation. Seedlings are normally raised in a nursery for up to 2 years before being transplanted to the field at the onset of the rainy season. In the nursery seedlings should preferably be grown in large containers (18 cm x 40 cm) to facilitate optimum development.
Propagation by rhizome cuttings (offsets) is possible if only few plants are required. For successful propagation, rhizome length should be at least 5 times the basal girth of a culm.
Propagation by culm cuttings (1-3 noded, planted horizontally), has been successful when they have been treated with root-promoting chemicals like coumarin, naphthalene acetic acid or boric acid.
In India, promising results have been obtained by tissue culture using explants from selected superior plants (node, shoot tip, base of leaf sheath, rhizome part, somatic embryo plantlets) and by a technique called macroproliferation in which young seedlings are forced to multiply by manipulating their young rhizomes (up to 7 times per seedling for B. bambos).
Recommended planting distances have not been reported but 6 m x 6 m seems to be appropriate.
Husbandry
B. bambos planted as a hedge around a farm or field requires little care.
A basal application of 5-10 kg farmyard manure or compost per plant before planting is beneficial to early growth. A later application of N fertilizer promotes growth and biomass production. Young plants must be watered, especially during prolonged drier periods. On a plantation scale B. bambos is a difficult crop. This bamboo is difficult to manage because of the thorny and interlacing branches of the culms in the clump. Dry and dead material has to be removed. Clearing the lowest 2 m of the clump enables culms from the centre to be reached. In South-East Asia, B. bambos forests are often natural grazing areas for domestic animals. A decline of those forests can be prevented by regulating the grazing periods and by maintaining the basal cover of the clumps by cutting culms at a higher level. In any case, after gregarious flowering of a natural bamboo forest, clear felling may only be practised after seedfall and the area should be rigidly protected against fire and closed to grazing.
Diseases and pests
B. bambos is usually only locally seriously damaged by diseases and pests. Major diseases reported from India are damping-off (Rhizoctonia sp., Fusarium spp.), culm rot (Fusarium spp., Arthrinium sp., Craterellus sp.), and rhizome and root rot (Merulius eurocephalus).
Major pests recorded in India are the bamboo leaf roller (Pyrausta coclesalis), the bamboo hispine borer (Estigmena chinensis), the bamboo aphid (Oregma bambusae) and the bamboo culm borer (Cyrtotrachelus dux). Most diseases and pests can be controlled satisfactorily by treatment with chemicals. Research towards 'environmentally friendly' control methods is starting.
Harvesting
Normally 3-4 year old culms are harvestable. They are cut 2-3 m above the ground. This should be done after the growing season in order to avoid damaging young shoots and young culms.
Clear felling of B. bambos clumps is practical but results in poor regeneration; the clumps remain in a congested and bushy state for 3-5 years and only after 5 years are new culms of sizeable length produced. The felling cycle in clear felling is 5-12 years.
Selective felling of individual culms results in better regeneration of the clump. Preferably, only culms older than 2 years are cut at 15-30 cm from ground level and if possible not from the periphery of the clump, so as to prevent congestion. At least half of the culms per clump, a minimum of 8-10, should be left. Extraction of rhizome parts for propagation should be prohibited and clear felling should only be allowed after flowering and fruiting.
Yield
In India culm yield is on average 5 t/ha per year, but may vary from 2.5-36 t. In Thailand an annual production of 5000-8000 culms per ha is reported.
Handling after harvest
In South-East Asia, traditional non-chemical methods to increase the durability of bamboo culms are widely used on a village scale, including curing, smoking, whitewashing and soaking. For preserving culms, chemical treatments are usually more effective than traditional methods. Fumigation with methyl bromide for insect control, brushing and spraying with 5% DDT, 0.5% gamma BHC or 0.5% dieldrin has proven to be effective against bamboo borers like Dinoderus brevis, D. minutus and D. ocellaris.
In India, good results have been obtained by dipping green culms in a solution of 1% lindane or 3% boric acid-borax mixture (1:2). The service life of culms can be extended by a treatment with boric acid, and, if used in ground contact, by immersing the butt end for 7 days in a 10% copper sulphate solution. Cheaper and safer methods for insect control and preservation are still in the experimental stage.
In some areas in India, B. bambos culms are grouped into 3 quality classes: class 1 with culms of 9 m or more long, class 2 with culms from 6-9 m, class 3 with culms up to 6 m long.
Genetic resources
No germplasm collections of B. bambos are known to exist. It is worthwhile to start living plant collections to preserve its rich variability.
Breeding
B. bambos is highly allogamous and provides opportunity for selection of desired characteristics. In India, seedlings are grouped into 4 types: grassy, grassy-erect, erect and very erect. The erect types grow fast and are more vigorous.
Other breeding techniques in the experimental stage include selection of mutants (e.g. thornless types), ploidy changes and somatic cell hybridization. Pollen of B. bambos can be stored well at 4ºC.
Prospects
B. bambos is considered an important raw material for the paper and pulp industry in South-East Asia. In the past, most of the culms supplied to the industry were collected from natural stands, resulting in the decline of natural B. bambos forests. For large-scale production, the cultivation of B. bambos is recommended. More research is needed on cultivation techniques and the development of superior cultivars of this very useful multipurpose bamboo.
S. Duriyaprapan and P.C.M. Jansen
For additional information about author(s) see Contributors or Editors.