Bambusa blumeana

Bambusa blumeana J.A. and J.H. Schultes

Syst. veg. 7: 1343 (1830).
2n = 78

Origin and geographic distribution
The exact origin of B. blumeana is not known, but it is believed to be native in Sumatra, Java, Lesser Sunda Islands and Borneo. For map click: Map498.TIF. It is found planted or cultivated in Peninsular Malaysia (northern provinces), Thailand, Vietnam, southern China and the Philippines. In the Philippines it was probably introduced in prehistoric times and can be found throughout the settled areas at low and medium altitudes.

Young shoots are eaten as a vegetable, usually boiled and shredded. The culms are used for construction, basketry (baskets are very popular), furniture, parquets, concrete reinforcements, kitchen utensils, chopsticks, hats and toys. Culms are also used as firewood if wood is scarce. The culms are suitable for making paper. It is often planted along water courses to prevent soil erosion. It is planted around farmhouses as wind-breaks, in fields as living fences or to mark boundaries.

Production and international trade In the Philippines B. blumeana is the most important bamboo used as building material, to make furniture and chopsticks, and for the production of paper. The Philippines exported bamboo furniture with a total value of US$ 741,505 in 1987. In Tarlac, 20 ha of B. blumeana have been planted for the export of chopsticks to Japan; 12,000 culms are produced per year, from which 1200 million chopsticks are made. No statistics are available from other countries in South-East Asia.

In culms of B. blumeana the number of fibrovascular bundles increases from 2.37/mm2 in the butt to 3.30/mm2 in the apex. The fibre dimensions are: length 1.95-2.56 mm, diameter 15-20 µm, lumen diameter 4-9 µm, wall thickness 5-7 µm. Fibre length increases from the 2nd to the 18th internode, after which it decreases. In the lower internodes fibre diameter and wall thickness are slightly larger. On average, the weight of a green culm is 32 kg, its branches 7 kg, its leaves 1.5 kg, and a culm has 65 internodes and 30 branches. At a moisture content of 94.5% culms have a density of 1000 kg/m3, at about 15% the density is 500 kg/m3. Shrinkage of culms at seasoning from green to oven-dry condition is about 8% in diameter and 13% in wall thickness. For green culms (moisture contents 94.5% and 136% respectively) the modulus of elasticity is 4110 N/mm2 and 9000 N/mm2, the modulus of rupture 110.9 N/mm2 and 32.1 N/mm2, the compression strength parallel to grain 27.1 N/mm2 and 38.3 N/mm2 and the shear strength 4.8 N/mm2. The chemical composition of mature culms on dry weight basis is approximately: holocellulose 67.4%, pentosans 19%, lignin 20.4%, ash 4.8%, silica 3.4%; the solubility in hot water is 4.3%, in alcohol-benzene 3.1% and in 1% NaOH 39.5%. Silica content is high and internodes are sometimes completely filled with a hard, white, siliceous mass which damages any instrument used to cut it.
Per 100 g edible portion, young shoots (7-15 days old) contain approximately: water 89 g, protein 4 g, fat 0.5 g, carbohydrates 4 g, fibre 1 g, ash 1 g, Ca 37 mg, P 40 mg, Fe 1.5 mg, vitamin B1 0.1 mg, vitamin C 10 mg. The energy value is about 120 kJ/100 g.

Densely tufted, sympodial bamboo, with spiny basal branches forming a densely interlaced thicket to 2-3 m high. Culm erect, 15-25 m tall, up to about 20 cm in diameter, wall 0.5-3 cm thick; internodes usually hollow, 25-60 cm long, glabrous, green; nodes prominent, the lower ones bearing aerial roots. Branches arising from nearly all nodes, the lower ones spreading horizontally and bearing stout straight or curved spines in groups of (1-)3(-5) (the central one usually larger and longer than the others), the upper branches ascending, branched at the base. Culm sheath up to 30 cm x 22 cm, the lower ones short and narrow, increasing progressively upwards, coriaceous, dull, the back covered with stiff, appressed, short, deciduous dark brown hairs; blade narrowly lanceolate, up to 15 cm x 1.5 cm, erect in basal and apical sheaths, horizontal to deflexed in middle sheaths, margins incurved, apex narrowly acute, glabrescent abaxially, adaxially with scattered, short, appressed dark hairs; ligule stiff, to 5 mm long, the middle tallest and shortly fringed, the outer parts with stiff bristles to 12 mm long; auricles on either side of the base of the blade, leathery, bearing numerous curved bristles 5-15 mm long. Young shoots with yellowish-green sheaths and blades. Leaf blade linear-lanceolate, 15-20 cm x 1.5-2 cm, base rounded, margins scabrous, apex narrowly acute; sheath striate; ligule truncate, short, fimbriate; auricles small, bearing a few bristles about 3 mm long. Inflorescence borne on leafy branches and on branches of a leafless culm, consisting of pseudospikelet groups 1-5 cm or more apart; spikelet laterally compressed, up to 5 cm long, comprising 2-3 empty glumes and 5-12 florets. Caryopsis is not known.

Growth and development
Planted culm cuttings at first send up thin shoots and culms are produced only after about 3 years. The number and size of the culms produced increases yearly until the clump reaches maturity. The following data are available from an experiment in the Philippines: 3 years after planting, per clump 2 culms with average height of 3 m were present; after 5 years 5 culms with average height of 8.5 m (maximum height 16.9 m, maximum diameter 10 cm). A planted cutting develops into a harvestable clump in 6-8 years. A mature clump (containing 10-40 culms) may develop about 30 shoots per year of which only about one-third to one-fourth reaches maturity because of diseases and pests, wind damage, and shortage of water and nutrients. Culms reach about full height in approximately 5 months, which means for the larger culms (25 m or more) a daily growth of about 17 cm. The most rapid growth usually occurs near the end of the growth period in the latter part of the rainy season. In that period, daily growth may reach 45 cm on average.
B. blumeana flowers very rarely, perhaps once in 20-30 years, and plants die after flowering. In the Philippines, sporadic flowering was observed in 1990; a 100-year-old clump had 6 flowering culms, a 45-year-old clump had 3 and 5 clumps of 3-year-old had 3-5; flowering extended from January to October, after which the culms died; no fruits were formed.

Other botanical information
Culm diameter and internode length vary greatly. The maximum culm diameter is attained at about 6 m above ground level, the internodes are shortest in the lower part of the culm. In the Philippines plants generally have longer internodes than plants grown in Indonesia and Malaysia.
B. blumeana much resembles B. bambos (L.) Voss, but they can easily be distinguished from each other by their culm sheaths. In B. blumeana the auricles of the culm sheath are prominent, bearing numerous curved bristles along the edges, whereas in B. bambos they are not auricle-like, but formed as extensions of the base of the blade, covered by dark brown hairs. B. blumeana does not grow as large as B. bambos and its culms are also less durable.

Where B. blumeana occurs in the wild, it grows up to 300 m altitude, often on heavy soils and on marginal land. B. blumeana grows well along river banks, hill slopes and freshwater creeks and it tolerates flooding. Optimum pH is 5-6.5; saline soils are not tolerated.

Propagation and planting
B. blumeana is propagated vegetatively by culm cuttings, branch cuttings, layering, marcotting and tissue culture. Propagation by culm cuttings is most common. Cuttings about 50 cm long (with 2-3 nodes) are taken from the middle portion of 1-2-year-old culms with a relatively large diameter. They are planted horizontally at 10 cm depth. Application of growth hormones, e.g. 200-600 ppm -naphthalene acetic acid (NAA), gives a better rooting rate and longer roots. They should be planted immediately in a nursery or directly into the field in direct sunlight. Before planting, the field is cleared and cuttings or rooted cuttings are planted at a distance of 8-10 m all sides, resulting in 100-150 clumps/ha. Planting is preferably done at the beginning of the rainy season. After planting, mulch is distributed around the plant.
In the Philippines good results have also been obtained with 3-noded-cuttings from branches, up to 1.5 cm in diameter, from 1-2-year-old culms. Treated with 100 ppm IAA and planted in a sand bed, the cuttings could be potted when rooted (after about 20 days) and transplanted to the field after 2-3 months.

During the first two years after planting, the plantation should be weeded whenever necessary. If rainfall is not sufficient, watering or irrigation is necessary during the initial period of development.
On poor soils, application of fertilizer is recommended, e.g. compost or a NPK mixture. A recommended rate per ha is in total 20-30 kg N, 10-15 kg P, 10-15 kg K and 20-30 kg silica, applied in two rounds, 1 month and 4 months after planting. Removal of spiny branches and old culm bases in the clump will increase culm production and improve access.

Diseases and pests
B. blumeana has no serious diseases or pests during growth. In the Philippines tar spot (Phyllachora shiriana) and leaf rust (Phakopsora louditiae) are common diseases on B. blumeana and mites (Schizostatranycus floresi) are most prevalent on the leaves. Young plantations should be protected against animals which eat young shoots. Harvested culms are liable to attack by fungi (brown, white and soft rot) and especially by insects (beetles, termites). For B. blumeana no specific data on deteriorating organisms have been reported.

Bamboo shoots emerge during the rainy season and can be harvested for food after 7-15 days. In B. blumeana plantations, the harvesting of culms may start 5 years after planting. The harvesting depends on the end use but should preferably be effected in the dry season. For handicraft purposes, 1-year-old culms can be taken. For construction purposes, 3-year-old culms are suitable. Culms are cut 2-3 m above the ground, just above the dense growth of spiny branches. The remaining basal portion should be cut back close to the ground within 6 months of the harvest. In order to ensure sustained yield, the number of culms that can be cut annually should not exceed 60% of the standing mature culms in the clump.
Removal of the basal spiny thickets and basal parts of harvested culms makes access easier, promotes the development of healthy shoots and reduces the number of deformed culms.

About 6-7 edible shoots can be harvested per clump per year. Managed (cleaned) clumps produce an average of 8 culms per year (800-1200/ha), unmanaged (uncleaned) clumps only 5 (500-750/ha). In the Philippines the marketable length of culms varies from 7-16 m, with diameter (at base) of 7-12 cm and average internode length of 34 cm. The average dry weight production ratio for culms, branches and leaves is 83.5%, 12.8% and 3.7% respectively. Standing crop production (dry weight) is estimated at 143 t/ha (120 t for culms, 18 t for branches, 5t for leaves). Per ha, about 9t pulp for paper can be produced per year.

Handling after harvest
Fresh harvested young shoots are washed carefully, sliced and boiled before they are sold in local markets. Harvested culms should be dried first. Air drying (in sheds) takes about 2-4 months, kiln drying 1-2 weeks, depending on required moisture content and drying conditions.
The natural durability of untreated culms is poor: 1-3 years outdoors, 2-5 years indoors, 6 months or less in seawater. Preservation treatment considerably increases the service life of culms and is recommended, but no specific data are available for B. blumeana.
In South-East Asia the traditional treatment of bamboo culms after harvesting is to soak them for about 2 months in running or brackish water before drying, or to expose culm pieces for some time to the smoke and heat of a fireplace.
Culms harvested for wickerwork are allowed to wither in the shade for 3-5 days, then the nodes are removed and each internode is split lengthwise into a number of pieces. The internodes from the middle of the culms are preferred. The inner material and the outer layer are removed. The remaining material is flattened and divided into 4-10 layers, the outermost layers under the skin considered the best.

Genetic resources and breeding
Germplasm collection of B. blumeana has been started in Indonesia (private company in Lampung (Sumatra) and Ministry of Forestry). Breeding programmes will be restricted to selection of superior genotypes, as B. blumeana rarely flowers.

B. blumeana has a promising future as a very useful bamboo for tropical lowlands. Large-scale cultivation started in the Philippines, e.g. as a pulp source for paper of various qualities, but could possibly be extended to other areas in South-East Asia as well. More research is needed on the optimal techniques for cultivation and preservation and other possible applications. To improve B. blumeana as a crop plant it is recommended to collect germplasm from all areas where it grows or is cultivated.

C.A. Roxas

For additional information about author(s) see Contributors or Editors.