Calamus caesius (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Calamus caesius Blume

Protologue: Rumphia 3: 57 (1849).

Family: Palmae

Chromosome number: 2n= unknown

Vernacular names

• Rotan sega (general throughout region and in trade)
• Indonesia: rotan sego (Sumatra), rotan taman (southern and central Kalimantan)
• Philippines: sika
• Thailand: wai ta kha thong.

Origin and geographic distribution

C. caesius is widespread in the wetter parts of SouthEast Asia, occurring in Peninsular Malaysia, Sumatra, Borneo, Palawan (the Philippines), and southern Thailand (possibly introduced). In recent years it has also been introduced to China and a few countries in the South Pacific for trial planting.

Uses

Traditionally, C. caesius has been used by rural people for making baskets, mats, carpets, handicrafts, cordage, and in house construction, and sewing of "atap"(thatch). The round cane, skin peel and core provide extremely important highquality materials for the now highly developed and very sophisticated rattan furniture manufacturing industry. Its unique glossy golden cane surface makes it highly sought after for making "tatami"mats or rattan carpets for the lucrative Japanese market. Its commercial usage has now surpassed traditional usage.

Production and international trade

Traditionally, C. caesius has been collected from the wild in Indonesia, Malaysia and the Philippines either for local use or to be sold commercially. In Kalimantan, however, C. caesius has been extensively cultivated by smallholders for probably over a century, particularly along Mentaya River in Central Kalimantan. In this region, it is commonly planted in abandoned rubber holdings, the old rubber trees being used for shade and support. In East Kalimantan, C. caesius has been incorporated into the swidden farm system. There are no authoritative statistics on annual production of C. caesius either from the wild or from cultivated areas, although it is certain that Indonesia has been the largest producer. In Malaysia, 30004000 ha of commercial plantations of this species have been established in stages over the last 10 years. In the near future, Malaysia will become a major producer.

C. caesius is collected or harvested and sold to middlemen either in the raw form or after some cleaning, fumigation and drying. Middlemen in turn sell to large processing factories which are also usually engaged in exporting it as washed and sulphured round canes, split canes, skin peels, woven chaircane or core. In the past, raw materials from Malaysia and Indonesia were exported to Singapore and Hong Kong for further processing, grading and packing before they were sold to end users in Europe, the Philippines, Taiwan and China which have well developed rattan furniture manufacturing capability and capacity. These traditional trade routes have been drastically altered recently by the introduction of increased export levies and bans aimed at increasing processing and manufacture in the producing countries, thereby adding value to the exports.

Properties

C. caesius has a resilient and durable cane with a smooth golden surface. It is particularly suited for making highquality rattan carpets ("tatami"mats) because of the siliceous glossy surface. The quality of the cane is adversely affected by poor processing; it also depends on factors such as age, moisture content and the light conditions during growth (which affect the internodal length).

Description

Clustering, moderatesized, highclimbing, dioecious rattan, with stems ultimately to 100 m or more long, the clump tending to be rather close and dense. Stem without leafsheaths 712 mm in diameter, with sheaths to about 20 mm in diameter; internodes to 50 cm or more long. Leaf to 2 m long including the sheath; leafsheath dullgreen, armed with sparse, pale, triangular spines to 10 mm×5 mm, between the spines with grey hairs and sometimes with minute spicules and/or brown scales; petiole up to 50 cm long in juveniles, very short in adult climbing stems; rachis c. 75 cm long, bearing scattered reflexed spines on the lower surface, distally the rachis prolonged into a whip (cirrus) c. 75 cm long, bearing grapnellike groups of reflexed spines; leaflets c. 15 on each side of the rachis, arranged irregularly, usually in alternate pairs, lanceolate, up to c. 30 cm×5 cm, the upper surface darkgreen, the lower surface usually conspicuously bluishwhite. Inflorescence borne on the leafsheath of the leaf above the subtending axil, to 2 m long, the male and female superficially similar, the male branching to 3 orders, the female to 2; bracts tightly tubular, sparsely spiny and hairy; firstorder branches 58, rather distant; flowerbearing branches rather slender, to 10 cm long in the female, shorter in the male; male flower greenishyellow, c. 5 mm×3 mm; female flower, larger than the male, each borne in a pair together with a sterile male flower. Mature fruit 1seeded, ovoid, c. 15 mm×10 mm, covered in neat reflexed greenishwhite scales, drying yellowish. Seed c. 12 mm×7 mm, with an outer fleshy seedcoat (sarcotesta); endosperm ruminate, embryo basal. Seedlingleaf forked, with the two acute lobes only a quarter the length of the whole leaf, and held parallel to each other, upper surface dark green, the lower surface greywhite.

Growth and development

Most seeds germinate within 34 weeks. After 1214 months the primary stem may exceed 1 m; the first climbing whips and 12 sucker shoots may have developed. As the plant grows older, more and more suckers will be produced every year, probably up to ten per year. Some of these will develop into aerial stems while others remain dormant as bulbillike shoots, thus forming a relatively compact cluster of aerial stems. By year 10, the number of aerial stems may vary from 20 to 60 or more per cluster, depending on conditions of growing site and weather.

Aerial stems may grow at rates exceeding 45 m per year. Annual flowering may commence at an age of 45 years. Up to 4 inflorescences may be produced on one flowering stem, with each infructescence bearing 10001500 fruits.

Other botanical information

C. caesius is closely related to C. optimus Becc. and C. trachycoleus Becc. Whereas C. caesius and C. optimus produce short horizontal stolons not exceeding about 8 cm, C. trachycoleus produces long horizontal stolons up to 1 m or more long. As a result, C. caesius produces a relatively compact cluster of aerial stems whereas C. trachycoleus has a diffuse colony of aerial stems which are more widely spaced and hence compete less with each other. The diffuse colony of C. trachycoleus makes it an aggressive colonizer and a potentially higher cane yielder.

Ecology

C. caesius is usually found in the lowlands on alluvial flats, seasonally flooded river banks, and margins of freshwater or peatswamp forest, but not in permanent swamps. In Borneo, where the greatest morphological variation occurs, it is also found on drier sites up to 800 m above sealevel. On these drier sites, growth is less vigorous. Although it flourishes under mild and seasonal floodings, the seedlings cannot withstand severe floods.

Propagation and planting

Although C. caesius can be propagated by using sucker shoots, cultivation is best effected using seed. Rattan fruits should be processed and sown as soon as possible after collection in order to maintain their viability. During processing, scales and sarcotesta are removed by repeated rubbing and washing. Cleaned seeds should be stored in a cool and shady place if they are not sown immediately after processing. Seeds are sown about 1 cm deep in a seedbed constructed under shelter. The sowing medium should be sandy loam or loam with a top layer of 2 cm of sawdust to enhance moisture retention in the sowing medium. Regular watering is essential to keep the seeds and sowing medium moist. Seeds may be treated with fungicide prior to sowing. Seedlings are potted in black polythene bags of about 15 cm deep and 15 cm in diameter when the shoots have emerged 23 cm above the sawdust. Seedlings are nursed in these bags for 9 months or more under semishade provided by plastic shading sheet, palm fronds or other appropriate materials. Regular watering, fertilizing with 510 granules of NPK compound fertilizer per seedling per month and spraying with some pesticides are routine maintenance measures. Seedlings 4050 cm tall are ready for planting out in the field. Rubber trees, bungor ( Lagerstroemia sp.) and even fruit trees have been used by smallholders to provide shade and support for C. caesius. Largescale commercial planting has been carried out under loggedover natural forest and plantation forest. While smallholders adopt haphazard spacing, commercial planting adopts a spacing of 2 m×10 m or 2 m×8 m.

Husbandry

Postplanting maintenance is relatively simple. Seedlings should be circleweeded manually for 23 years. Overhead shade should be manipulated at about 6monthly intervals for 23 years to ensure seedlings receive sufficient light to grow vigorously. About 50% light/shade conditions are ideal for rattan growth. A path 1 m wide may be maintained in the planting row to allow easy access and maintenance. NPK compound fertilizer needs to be applied at 6monthly intervals if soil conditions are poor. Pesticide application has not been necessary.

Diseases and pests

In the nursery, disease and pest attack is usually minimal if strict nursery hygiene is observed. However, seedlings may suffer leafspot diseases caused by Curvularia, Colletotrichum, Phomopsis and Pestalotiopsis species. Severely infected leaves will dry up. These diseases can be controlled by applying fungicides. Leaf blight caused by Colletotrichum gloeosporioides is more serious and may kill the seedlings in a few weeks. It can be controlled with fungicide applied at 10day intervals. In the field, individual shoots may be attacked by rats, squirrels, porcupines and an unidentified weevil. In Sabah, elephants are known to pull out seedlings or feed on the shoots. Wild boars will uproot seedlings as they forage for roots and worms.

Harvesting

Selective harvesting of mature canes can be carried out in the eighth year after planting. Harvesting is carried out by cutting the rattan cane at about 30 cm from the base, pulling the cane down out of the canopy as much as possible, removing the leafsheaths by twisting the cane around a tree trunk or hitting it with a knife. The cane, divested of its sheaths, is then cut into lengths of about 6 m and bent, and tied in bundles of 100 pieces. Inevitably, lengths of canes will be left in the canopy and cannot be pulled out because they are entangled with the tree branches. More efficient mechanical methods of harvesting for large commercial plantation have yet to be developed. Canes should be processed soon after harvesting, in order to maintain their quality.

Yield

Highly variable figures, ranging from 1.53 t/ha per year, have been provided by cultivators and researchers. Based on a surviving population of 500 plants/ha in a commercial plantation, a cane growth rate of 2.5 m/year and 36000 m of dry canes to yield one ton, the yield has been estimated to increase from 0.5 t/ha per year in year 9 from planting to 1.5 t/ha per year in year 12 and thereafter.

Handling after harvest

Postharvest treatment of canes involves washing to remove mud and remaining leafsheaths, drying, and sulphur fumigation to prevent attack by diseases and pests and to improve cane colour.

Genetic resources

C. caesius has been collected and planted in a number of botanic gardens and arboreta in several countries. Recently, different provenances of this species have been collected for provenance trials by the Sabah Foundation in Sabah, Malaysia.

Breeding

No breeding work has been carried out on C. caesius . Primary selection and provenance trials are needed before a breeding programme can be initiated.

Prospects

Supply of C. caesius from natural forests has been dwindling fast, especially in Malaysia and the Philippines, due to overexploitation and destruction of its natural habitat when forest is converted for agriculture. Rich alluvial flats and other fertile land where C. caesius used to thrive best have practically all been converted to agricultural land. In Indonesia, fortunately, there is a long tradition of cultivating C. caesius by smallholders, thus very significantly supplementing supply from the wild. Rattan cultivation has provided a very important source of income for large numbers of otherwise impoverished smallholders, especially in Kalimantan. Several Indonesian companies have also started cultivating this rattan on a commercial scale as in Malaysia by government bodies and private companies.

Literature

• Dransfield, J., 1979. C. caesius and C. trachycoleus compared. Gardens' Bulletin, Singapore 30: 7578.
• Dransfield, J., 1979. A manual of the rattans of the Malay Peninsula. Malayan Forest Records No 29. Forest Department, Kuala Lumpur. p. 135.
• Godoy, R. & Tan ChingFeaw, 1991. Agricultural diversification among smallholder rattan cultivators in Central Kalimantan, Indonesia. Agroforestry Systems 13: 2740.
• Lembaga Pengembangan Perbankan Indonesia Proyek Pengembangan Agro Industri, 1989. Industri mebel rotan di IndonesiaStudi sektor [Rattan furniture industries in Indonesiasectoral study]. 83 pp. and 10 pp. appendix.
• Norani, Ahmad & Maziah, Zakaria, 1988. Diseases of Calamus spp. (Rattan). FRIM Technical Information No 4. 4 pp.
• Shim, P.S. & Momen, M.A., 1985. A preliminary report on the growth forms of Calamus caesius and C. trachycoleus in SAFODA's Kinabatangan rattan plantation. In: Wong, K.M. & Manokaran, N. (Editors): Proceedings of the rattan seminar, Kuala Lumpur, 24 October 1984. Rattan Information Centre, Forest Research Institute of Malaysia, Kepong. pp. 6371.
• Weinstock, J.A., 1983. Rattan: ecological balance in a Borneo rainforest swidden. Economic Botany 37: 5868.

Authors

C.F. Tan & P.S. Shim