Borassus flabellifer (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Borassus flabellifer L.

Protologue: Sp. pl.: 1187 (1753).

Family: Palmae

Chromosome number: 2n= 36

Synonyms

Borassus flabelliformis L. (1774).

Vernacular names

• Toddy palm, wine palm, palmyra palm (En). Palmier à sucre, rônier, rondier (Fr)
• Indonesia: lontar (general), tal (Java), siwalan (Sumatra), tala (Sulawesi)
• Malaysia: lontar, tah, tai. Burma (Myanmar): tan bin
• Cambodia: thnaôt
• Laos: ta:n
• Thailand: tan (general), tan-yai (central), not (southern)
• Vietnam: thốt nốt, thốt lốt.

Origin and geographic distribution

B. flabellifer is distributed from India through South-East Asia to New Guinea and North Australia. It is particularly abundant in India, Burma (Myanmar) and Cambodia, where it is frequently planted. It is almost generally assumed that B. flabellifer is a selection by man from the more diverse B. aethiopum Mart. of Africa. Its distribution probably followed Indian trade routes in prehistoric times.

Uses

All parts of the toddy palm are used. In India it is called the tree with 800 uses. The main product is the sap obtained from tapping the inflorescences (in B. aethiopum : tapping of the growing point of the trunk), which may be drunk immediately or be processed into sugar or be allowed to ferment for a few hours to become toddy. This mild palm wine with 5-6% alcohol content may later be converted into distilled ethanol (arrack) or vinegar. The leaves were formerly used to write on. They may still be used as thatch ("atap") and are said to last at least two years. They are also used for baskets, brushes and buckets; the fibres of young leaves can be woven into delicate patterns. Petioles are often used as poles for fencing or as firewood and can be split into fibre, to be used for weaving and matting. The lowest 10 m of the trunk has hard and strong wood, good for constructing buildings and bridges. The somewhat softer middle part can be split into boards. The soft upper 10 m of the trunk contains some starch, which may be harvested in times of food scarcity. The wood and leaves are also used as fuel. The seedlings (underground and tuber-like) are sometimes grown for use as a starchy vegetable, and eaten boiled or raw, but they may be slightly toxic. In Burma (Myanmar) they are considered a delicacy. The growing point of the palm (palm heart or palm cabbage) is also edible. The tender mesocarp of young fruits is cooked in curry. The ripe fruit has a yellow edible pulp with a distinctive aroma. The young solid or gelatinous endosperm of the seeds is also eaten fresh or in syrup. In Burma (Myanmar) and Cambodia, toddy palms are often planted as a windbreak or to delimit fields. Innumerable traditional medicinal uses are known for all parts of the toddy palm.

Production and international trade

Toddy palm is mainly grown for subsistence and is primarily produced by smallholders. Surplus production may be sold on local markets. No statistics are available on production and trade, but there are some statistics on palm stands. In Sri Lanka there are 10 million palms on 25 000 ha (two-thirds in Jaffna district), and in India 60 million palms (two-thirds in Tamil Nadu). Central Burma (Myanmar) has 2.5 million palms on 25 000 ha, and central Cambodia has 1.8 million palms. In 1968 the toddy palm sugar production in Cambodia was estimated at 35 000 t per year, and the national consumption at 10 000 t. Stands in Thailand have nearly been eradicated. In Indonesia toddy palm is found in Central and East Java and on Madura, totalling 0.5 million palms on 15 000 ha. There are also large stands in Sulawesi and on the Lesser Sunda Islands, and some in the Moluccas and in south-eastern Irian Jaya. In Burma (Myanmar) and Cambodia smallholders own 30-40 toddy palms on average (25 male, 15 female trees).

Properties

The sap of toddy palm contains 17-20% dry matter. It has a pH of 6.7-6.9(-7.5) and per litre contains some proteins and amino acids (360 mg N), sucrose 13-18%, P 110 mg, K 1900 mg, Ca 60 mg, Mg 30 mg, vitamin B 3.9 IU, and vitamin C 132 mg. The 7-9 g/l reducing sugars are probably formed through enzymatic or microbiological reactions immediately after tapping. The ash content of the sap is to 4-5 g/l.

A rather large fresh fruit may weigh 2790 g (100%): perianth lobes 175 g (6.3%), exocarp 120 g (4.3%), mesocarp fibre 66 g (2.4%), mesocarp edible pulp 1425 g (51.0%) and 3 seeds 1004 g (36.0%). The 3 seeds consist of shell 394 g, endosperm 609 g and embryo 1 g.

Description

• Robust, 25-40 m tall, solitary, pleonanthic, dioecious palm. Stem massive, straight, up to 1 m in diameter at base, conical up to about 4 m high, thereafter cylindrical and 40-50 cm in diameter, occasionally branched, covered by leaf bases when young, rough and ringed with leaf scars when older, fringed at the base with a dense mass of long adventitious roots.
• Leaves (30-)40(-60), arranged spirally, leathery, induplicate, strongly costapalmate; sheath open when young, later with a wide triangular cleft at the base of the petiole; petiole woody, 60-120 cm long, deeply furrowed; margins of sheath and petiole armed with coarse, irregular teeth; blade suborbicular to flabellate, 1-1.5 m in diameter, divided along adaxial folds to about half its length into 60-80 regular, stiff single-fold segments that are about 3 cm broad at base.
• Inflorescence interfoliar, peduncled, shorter than the leaves, the male and female dissimilar.
• Male inflorescence massive, up to 2 m long, consisting of about 8 partial inflorescences of three rachillae each; rachilla spike-like, fleshy, 30-45 cm long, bearing spirally arranged imbricate bracts, connate laterally and distally to form large pits, each containing about 30 flowers, exserted singly in succession from the pit mouth; flowers 3-merous with 6 stamens.
• Female inflorescence unbranched or with a single first order branch, covered with sheath-like bracts; rachilla massive, fleshy, thicker than the male one, bearing large cupular bracts, the first few empty, the subsequent ones each subtending a single female flower with several empty bracts above the flowers; flowers larger than male ones, 3-merous, tricarpellate.
• Fruit a globose to subglobose drupe, 15-20 cm in diameter, 1.5-2.5(-3) kg in weight, dark purple to black; petals persistent, brittle, not imbricate; exocarp smooth, thin, leathery; mesocarp thick, juicy, fibrous, often fragrant, yellowish; endocarp usually comprising 3 hard bony pyrenes.
• Seed shallowly to deeply bilobed, pointed; endosperm sweet and gelatinous when immature, hard and ivory-like with a central cavity when mature.

Growth and development

Normally when planted, seed of toddy palm starts to germinate within 45-60 days. Germination is remote-tubular, i.e. a tubular sprout (hypocotyl) emerges from the seed, protected by a cotyledonary sheath, and grows down into the soil up to 90-120 cm depth; the top of the sprout becomes tuberous, about 15 cm long and 2.5 cm wide, and stores nutrients from the endosperm of the seed. When growth continues the tuberous part sends forth roots, separates from the sheath and begins to grow upright. In 9-12 months the tip of 1-2 sword-shaped eophylls (first seedling leaves with a blade) emerge above the ground, after which true leaves follow. After a rosette-stage of 4-6 years, trunk formation starts. The trunk grows about 30 cm in height per year. Under optimal ecological conditions 14 leaves unfurl per year, or one leaf per 26 days. The crown then possesses up to 60 leaves. The longevity of unfurled leaves can thus be estimated at 4 years and 4 months. Under marginal ecological conditions, only 8 leaves unfurl per year, or one leaf per 45 days. The crown then possesses 30 visible leaves. Leaf longevity is then 3 years and 9 months. The palm starts flowering and fruiting 12-20 years after germination, usually in the dry season. Under optimal ecological conditions (e.g. sufficient water supply) more leaves and up to 50% more inflorescences are produced than under marginal conditions. Toddy palms can become very old (over 150 years), but their economic lifetime is about 80 years (older trees become too tall to be exploited safely).

Other botanical information

The widespread fan-palm of the less dry areas of tropical Africa is B. aethiopum Mart. In the literature, B. aethiopum has often been considered synonymous with or retained as a variety under B. flabellifer. B. aethiopum , however, is a much more massive plant than B. flabellifer, often with a ventricose stem and leaves with very many more completely rigid leaflets forming a gently undulating leaf surface. In B. flabellifer the stem is not ventricose and the leaves have fewer, less rigid leaflets, forming a deeply grooved surface. The Borassus, occurring in Indonesia from East Java eastwards, differs slightly from B. flabellifer (petals in fruit imbricate at the base, absence of scales on the leaf blades, less branched male inflorescence) and has been described as a different species: B. sundaica Beccari. In this article, B. sundaica is for the time being considered to be conspecific with B. flabellifer.

Ecology

Toddy palm is mainly cultivated in the drier parts of its geographical range, where the sugar palm (Arenga pinnata (Wurmb) Merrill) and the coconut (Cocos nucifera L.) cannot compete. It is usually grown in strictly seasonal tropical or subtropical climates on sandy soils. It is a very adaptable palm, however, growing well in dry areas with 500-900 mm average annual rainfall and is quite drought resistant. It also grows in per-humid areas with up to 5000 mm average annual rainfall and survives waterlogging quite well. Its optimum mean annual temperature is around 30°C, but it withstands extreme temperatures of 45°C and 0°C as well. It can be found on any kind of soil, preferring soils rich in organic material. It prefers altitudes around sea-level, but can be found up to about 800 m altitude. Toddy palms very often provide shelter to many animals (birds, bats, rats, squirrels, mongooses, monkeys) and plants (orchids, ferns and other epiphytes).

Propagation and planting

Toddy palm is propagated solely by seed. Large healthy seeds are sown 10 cm deep and spaced 3-6 m apart, preferably directly in the field because seedlings are difficult to transplant. They are usually planted in groups, in order to facilitate tapping.

Husbandry

Toddy palm does not require much attention once it has established. It responds well to water supply and manure. To tap the inflorescences, some leaves are cut away for easy access. Palms are cut down when they become too tall to be climbed easily. Thinning the plantations to favour more productive female trees is recommended. In Burma (Myanmar) and Cambodia, toddy palm is usually cultivated by smallholders as a cash crop in addition to their main product, rice. Working time has to be divided between the two crops: rice usually requires most labour in the wet season, toddy palm in the dry season.

Diseases and pests

Toddy palm hardly suffers from diseases and pests. Toddy palms growing in rich black soil or soil liable to flooding may succumb to bud-rot, caused by the fungus Phytophthora palmivora , also occurring on the more widely cultivated coconut. The first symptoms are spots on green leaf blades, which spread inwards to the bud. The bud then starts to rot and putrifies. The fungus can successfully be combated by killing and burning diseased palms.

Termites may occasionally attack seedlings. Certain beetle species (Oryctes and Rhynchophorus) feed on dead plant material, but may at dense populations become harmful for living palms. It is therefore necessary to clean stands of all kind of debris. Snakes and other venomous creatures sheltering in the crown may present a hazard to the tapper.

Harvesting

Tapping normally starts when the palm is 25-30 years old and may continue for 80 years. To harvest sap, the tapper must climb the palm trunk just before the inflorescences open. The leaves below the point of tapping are cut off so that the inflorescences can be reached, and the rather strong spines on the petioles of other leaves close to the tapping point are trimmed off. In male palms a number of partial inflorescences (usually about 12) are tied together after the flower buds have been stripped off. The stalks of these inflorescences are then systematically squeezed with tongs daily. After three days the tops of the stalks of the inflorescences are cut off and a bucket made of a leaf of the palm is hung on the end. This leaf bucket is supported by a basket, also made from a palm leaf or from bamboo internodes (Thailand). In female palms the inflorescences are handled individually: flowers are broken off and the flowering stalks are then squeezed for a number of days with larger tongs, to make them supple enough to be bent into the bucket, and to enhance the sap flow. Each morning the tapper climbs the palm, removes the bucket with sap and empties it into a container. In order to prevent early fermentation the sap receptacle has to be cleaned thoroughly. Sometimes tappers have two buckets, one is hung in the sun after cleaning, while the other is in use. The next day the buckets are interchanged. Two buckets are generally used if the sap is to be sold fresh. If there is only one bucket, some slaked lime (Ca(OH)₂) is put into it to prevent fermentation and deterioration; this affects the flavour of the sap. If bamboo buckets are used, they are placed on a fire for a moment after thorough cleaning. Small pieces of bark from various tree species containing tannins (e.g. Shorea roxburghii G. Don, Lannea coromandelica (Houtt.) Merrill), or the leaves of Anacardium occidentale L. and Schleichera oleosa (Loureiro) Oken are used as a substitute for slaked lime. For each tapping a new slice as thin as possible is cut off from the tapped end of the stalk with a razor-sharp knife kept especially for this purpose. In the evening the operation has to be repeated. The nightly flow of sap is nearly double that of the flow in daytime. A tapper may be able to handle 30-40 palms in a working day. The more skillful of the tapper is in climbing and tapping, the better the yield. On Madura, Timor, Sawu and Roti, where palm tapping still is practised on a sizable scale, bamboo scaffolding may be erected to make it easier for tappers to move from one palm to another high above the ground. The tapper then has a helper, who walks along on the ground, carrying a larger receptacle for the sap. The sap flow of an individual tree may continue for 3-6 months per year. If the fruits of toddy palm can be sold, as in Madura, tapping is restricted to male palms.

Yield

The sap obtained through tapping comes from the phloem. The sugar in the bleeding sap is derived from photosynthates, either directly from the leaves or indirectly after storage as starch in the trunk. The starch stored in the top of the trunk should be considered as a reserve that the plant can draw on in less favourable periods. Although both male and female inflorescences of B. flabellifer are tapped, the latter are preferred because of their higher yields. The sap in the inflorescences is intended to enable the plant to produce flowers, fruits and seeds, but much more can be produced than is necessary for this purpose, and therefore it can be "milked". The annual production of palm sap varies from 100-600 l per palm and the corresponding sugar yields vary from 16-70 kg per palm. Sugar yields of 19 t/ha per year are possible at a density of 275 palms per ha. The yield varies greatly between palms.

If toddy palms are cultivated for their fruits, yield per tree averages 200-350 fruits per year, i.e. up to 130 t per year if there are 275 female trees per ha.

B. aethiopum is normally tapped from the terminal bud; this causes the tree to die. Sap yields can be as high as 6 l per day and 169-246 l per year per palm. In some areas it is tapped by making an incision in the stem; it can stay alive after such tapping. The sap in the terminal bud or the stem normally fuels tree growth.

Handling after harvest

After harvest the sap may be boiled down into brown palm sugar. It is strained through a coconut leaf sheath sieve to remove debris and the added bark or leaf parts, and is then poured into an open pan that is heated. When the liquid thickens it is poured into half coconut shells and allowed to cool and solidify. This sugar is highly hygroscopic, as it contains all the dry matter from the sap. The quality of the sugar is good. In Indonesia for example, the fine toddy palm sugar from Madura is superior to that made from Arenga in West Java and commands better prices on Javanese markets. If no slaked lime is used, the sap may start fermenting in the bucket while this is still hanging on the palm. It may then be used as palm wine or toddy. The wine can be distilled, thus becoming arrack with an alcohol percentage of 20-60%. To make vinegar the palm wine must be kept in a cool and dark spot for some time.

In areas where the local production of toddy palm sugar is wholly dependent on the availability of wood as fuel, wood is often a limiting factor (e.g. in Burma (Myanmar) and Cambodia). About 5 kg wood is needed to produce one kg sugar.

Genetic resources

No germplasm collections of toddy palm are known to exist.

Breeding

There are no records of any breeding or selection work. Only in the state of Tamil Nadu (India) is some research on genetic variation being done. The genotypes in use have probably been selected by man for over 2000 years.

Prospects

The main impediment to regular cultivation of toddy palm is the long juvenile period of 8-14 years. Under favourable ecological conditions other palms with a shorter juvenile period will be preferred for tapping. A second impediment is the rather high labour requirement for tapping and the large amounts of fuel (wood) needed for preparing the sugar. Only under seasonal climatic conditions in areas with an excess of cheap labour and ample availability of wood for fuel can toddy palm still have a competitive advantage. Toddy palm is under pressure in all the countries where it is grown. In areas where coconut can be grown, toddy palm may be eradicated for phytosanitary reasons.

Literature

• Davis, T.A. & Johnson, D.V., 1987. Current utilization and further development of the palmyra palm (Borassus flabellifer L., Arecaceae) in Tamil Nadu State, India. Economic Botany 41: 247-266.
• Dransfield, J., 1976. Palm sugar in East Madura. Principes 20: 83-90.
• Fox, J.J., 1977. Harvest of the palm. Harvard University Press, Cambridge, Massachusets, United States. 290 pp.
• Kovoor, A., 1983. The palmyrah palm: potential and perspectives. FAO Plant Production and Protection Paper No 52. Food and Agriculture Organization, Rome, Italy. 77 pp.
• Lotwan, Udom, 1985. The culture of the soft yellow mesocarp of palmyra palm (Borassus flabellifer) in Thailand [in Thai]. Chao-Kaset Journal 4(46): 23-28.
• Lubeigt, G., 1977. Le palmier à sucre, Borassus flabellifer L., ses différents produits et la technologie associée en Birmanie [The sugar palm, Borassus flabellifer L., its different products and associated technology in Burma]. Journal d'Agriculture Traditionelle et de Botanique Appliquée 24(4): 311-340.
• Morton, J.F., 1988. Notes on distribution, propagation, and products of Borassus palms (Arecaceae). Economic Botany 42(3): 420-441.
• Romera, J.P., 1968. Le Borassus et le sucre de palm au Cambodge [Borassus and palm sugar in Cambodia]. l'Agronomie Tropicale 23: 801-843.
• Sambou, B., Lawesson, J.E. & Barfod, A.S., 1992. Borassus aethiopum, a threatened multiple purpose palm in Senegal. Principes 36: 148-155.

Authors

M. Flach & Y. Paisooksantivatana