Arenga pinnata

Arenga pinnata

The sugar palm or areng palm, black sugar palm, and kaong palm, black-fiber palm (Arenga pinnata (Wurmb) Merr., 1917) is an arboreal species belonging to the Arecaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Liliopsida,
Arecales Order,
Arecaceae family,
Genus Arenga,
Species A. pinnata.
The term is basionym:
– Saguerus pinnatus Wurmb.
The terms are synonyms:
– Arenga gamuto Merr.;
– Arenga griffithii Seem.;
– Arenga griffithii Seem. ex H.Wendl.;
– Arenga saccharifera Labill. ex DC.;
– Arenga saccharifera Labill., 1801;
– Borassus gomutus Lour.;
– Caryota onusta Blanco;
– Gomutus rumphii Corrêa;
– Gomutus saccharifer (Labill. ex DC.) Spreng.;
– Gomutus vulgaris Oken;
– Saguerus gamuto Houtt.;
– Saguerus rumphii (Corrêa) Roxb.;
– Saguerus rumphii (Corrêa) Roxb. ex Ainslie;
– Saguerus rumphii (Corrêa) Roxb. ex Fleming;
– Saguerus saccharifer (Labill. ex DC.) Blume;
– Sagus gomutus (Lour.) Perr..

Etymology –
The term Arenga comes from aren(g), the Malay vernacular name of a palm belonging to this genus.
The specific epithet pinnata comes from pínna penna, feather: with the shape of a pen or, by extension, winged, in reference to the appearance of the leaves.

Geographic Distribution and Habitat –
The Arenga pinnata is a palm native to tropical Asia where the range extends from India, through the Indochinese peninsula, up to Malaysia, Indonesia, and the Philippines.
Its natural habitat is usually near human settlements, often as a result of human activity, otherwise it prefers secondary forests bordering primary rainforests; moreover, it is often found in nutrient-poor sites and mesic sites such as bare slopes, up to 1,400 m. of altitude.

Description –
The Arenga pinnata is a medium-sized palm, with a single trunk, which can reach 20 m in height, with a trunk with a diameter of around 40 cm, covered by the persistent bases of the leaves and by long fibers and dark thorns. It is a monocarpic species (after fruiting, which lasts a few years, it dies).
The leaves are erect, 6-12 m long and 1,5 m broad, pinnate, with the fins in 1-6 rows, 40-70 cm long and 5 cm broad; they are irregularly notched at the tip, inserted on the rachis at various angles; the color is dark green above and greyish below.
The plant produces drooping, branched inflorescences, which follow one another from top to bottom and bearing either only male or only female flowers, but always on the same plant.
The fruit is subglobose, 7 cm in diameter, green in color which turns black when ripe. Inside it contains two to three seeds, yellow in color and must be handled with caution due to the presence of irritating oxalic acid in the pulp.
The fruits take a few years to ripen.

Cultivation –
Arenga pinnata is a palm commonly grown in tropical Asia due to its year-round food production and many other uses.
It is a particularly useful plant as it is a source of food in the dry season when other foods are scarce.
This palm is typical of the humid, lowland tropics, where it is found at altitudes of up to 1,400 metres. It grows best in areas where annual daytime temperatures are between 22-28°C, but can tolerate 16-32°C.
It prefers an average annual rainfall between 3,000 and 3,500 mm, but tolerates 2,000 – 4,000 mm.
Soil wise, it prefers deep fertile soil that retains moisture but is well drained, with a pH in the range of 6 – 7, tolerating 5 – 8.
The plant grows well in full sun, even if small.
It usually produces its first flowers around 10 – 12 years old, although it can flower as early as 5 – 6 years old.
Depending on altitude and temperature, and to a lesser extent factors such as soil fertility, climate and competitive vegetation, palms will remain in the rosette phase for 3.5 to 6 years, then reach full size in another 3 to 9 years.
Usually, after 5 – 6 years, the fibers can be harvested for the first time and every 2 years thereafter.
When the palm begins to flower, the sweet sap can begin to be tapped, but farmers usually wait for the first male flowers. Sap is usually taken only from the stems of male inflorescences, because female inflorescences are said to produce lower quality sap and the more fibrous stem of females requires extra effort to prepare. Usually, the closer the male inflorescence is to the ground, the less sap it produces. One inflorescence can produce about 5 liters of sap per day. One sugar palm bud can be harvested for 1 – 2 months and 2 – 4 buds can be harvested at a time.
A large quantity of starch is obtained from the trunk (each trunk can contain up to 75 kg of starch).
Since sago, the starchy layer on the inside of the trunk, is obtained only by cutting trees, it is usually the last product obtained; trees are usually cut for sago when they are over 30 years old.
The black roots are very strong, extending up to 10 meters from the stem and reaching up to 3 meters deep.
Propagation can take place by seed which must be pre-immersed for 24 hours in warm water and sown in deep containers. Alternatively, scarify the seed near the germination point until the brown inner layer of the seed coat is visible, then soak it in water overnight.
The seeds should then be sown in clean soil with good aeration, planted with the germination point down and covered with a 1cm layer of sand. Sand should always be kept moist.
Within 2-3 weeks about 80% of the seeds will have germinated and can be transplanted into any type of container.
Germination varies from 2 to 12 months or more.
Direct sowing is possible but the seedlings take a long time to take root well and can grow at irregular distances. Freely dispersed untreated seeds show 10-20% germination after 6 months.
Plants can also sometimes be propagated via suckers; these are globose, with a diameter of 3-4 cm.

Customs and Traditions –
The Arenga pinnata is known by various names, among which we mention: “sugar palm” (Italian); “areng palm”, “black-fiber palm”, “black sugar palm”, “gomuti palm”, “sugar palm” (English); “palmier à sucre” (French); “Zuckerpalme” (German); “gomuteira”, “palmeira-do-açucar” (Portuguese); “barú”, “bary”, “palma de azúcar”, “palmera del azúcar” (Spanish).
As with many plants widely cultivated since ancient times, the exact place of origin is not known, it is assumed that it is native to the humid forests of India and Malaysia, from where it has spread throughout Southeast Asia.
The species still has a considerable economic importance in the countries of south-eastern Asia; in fact, from this plant we obtain a sugar obtained from the lymph, and its derivatives, and the resistant fibers used, even if less than in the past, for multiple purposes.
In the Philippines, an annual Irok festival is celebrated in Indang municipality in Cavite, one of the leading producers of kaong, sukang kaong and tubâ fruits in the country. Irok is a local name for Arenga pinnata in the northwestern Philippines.
According to Sundanese folklore, the spirit known as Wewe Gombel dwells in the Arenga pinnata palm, where he also makes his nest and keeps the children he kidnaps.
However, its most popular product is its sap, taken from flowering stems, which is used to make a sugar.
The fruits, on the other hand, are poisonous and are sometimes used in a criminal way.
The fleshy mesocarp of fruits usually contains many oxalate crystals, making the pulp inedible.
Among the edible uses, however, a drink and sugar are obtained from the sweet sap obtained from the flowering stems.
The leaves are eaten cooked and the apical bud, known as the “heart of palm”, is sometimes used for food. It can be eaten raw in salads or cooked as a vegetable; however the removal of this shoot will result in the death of the plant, as it is unable to produce lateral shoots.
A sago-like flour can be ground from the pith of the trunk and used for cakes, noodles, and other dishes.
A product typically made from the plant is known as kolang kaling: this is the cooked endosperm of the young sugar palm fruit. One infructescence produces about 4,500 endosperms. It is used for a cocktail and local refreshment known as kolak.
In its medicine, the roots are used as a decoction of tea used to treat bladder disorders.
Other uses include agroforestry.
The plant has an extensive root system, up to 3 meters deep and 10 meters wide and was planted, especially on slopes, for soil stabilization.
In addition, the leaf sheath is a source of a hard, black fiber (gomuti or yonot fiber). It is not flexible enough to be used for such purposes as running rigging, but it is very strong and durable and mainly used to make cables and a very strong rope which tolerates both fresh and salt water and fire; it is used for marine work, straw, upholstery and brushes.
The dark fibrous bark is made into cordage, brushes, brooms, thatched roofs or filters.
According to the study of bas-reliefs of ancient Javanese temples such as Borobudur, this type of roof is known in ancient Javanese vernacular architecture. It can be found today in Balinese temple roof architecture and Minangkabau Rumah Gadang gonjong horn-like curved roof architecture, such as those found in Pagaruyung Palace.
The hairs found at the base of the leaf sheaths are excellent tinder for starting fires.
The fiber, placed at the bottom of a container, is useful for filtering, purifying the water of its physical impurities.
At the base of the leaves is a woolly material used for caulking ships and stuffing pillows.
Old woody leaf bases, as well as long leaves, can be used for fuel.
Split petioles are used for wickerwork and a form of marquetry. The younger leaves are sometimes used as cigarette paper.
The leaves are used as a source of straw material, the roots are a useful insect repellent.
The trunks of dead trees are left to rot and become hollow and are then used as water pipes.
The leaf rachis pith is an ideal shape for use as a glass.
The very hard outer part of the trunk is used for barrels, flooring and furniture. Pepper vine posts, planks, tool handles, and musical instruments such as drums are all made from wood.
From the ecological point of view it is not a threatened species, even if locally it is rare in some parts of its range. It serves as an important part of the diet of several endangered species, including mice of the genus Phloeomys. Furthermore, the A. pinnata suffers from the red palm weevil, Rhynchophorus ferrugineus. In China it is one of the main hosts of R. ferrugineus.

Method of Preparation –
The Arenga pinnata is a palm tree from which a sap is obtained which is harvested for commercial purposes in Southeast Asia, as it contains a sugar, known in India as jaggery or gur or in Indonesia as gula aren, and can be fermented to produce wine and vinegar.
The sap is harvested predominantly in Southeast Asia. The sap is collected and made into lahang, a traditional cold sweet drink, and is also fermented into vinegar (Filipino sukang kaong), palm wine (Filipino tubâ, Malay and Indonesian tuak, in eastern Indonesia sageru), which in turn is distilled into a spirit (sopi in Moluccas, cap tikus in north Sulawesi).
The sap is obtained by beating and bruising the developing inflorescence, which is then cut off and a juice is obtained from the cut end for a period.
The leaves are used as a cheap material for the roofs and walls of houses while their ribs are used to make brooms and baskets.
The fibers, called doh, gomuti or cabonegro, are used to produce very durable and resistant brushes and ropes.
Finally, the fruit is edible but must be suitably prepared before consumption due to the causticity of the juice and pulp.
Edmund Roberts talks about drinking an alcoholic beverage made in the Cavite area. He described it as a “fermented liquor” and “intoxicating”. He said it was “the marrow furnished with sugar—when the liquor was duly boiled, a flour … and of the inside of its triangular-shaped fruit a sweetbread was made.”
The sugar obtained (jaggery) is traditionally prevented from fermenting by placing chilli or ground ginger in the collection container. The sap is boiled down to a thick syrup which is then dried in brown sugar. Similar sugar extraction methods are also traditionally used for other sugar palms, such as Corypha elata.
The immature fruits are widely eaten in the Philippines (called kaong) and Indonesia (called buah kolang-kaling or buah tap) and are made into canned fruit after being boiled in sugar syrup.
The dark fibrous bark is made into cordage, brushes, brooms, thatched roofs or filters.
The leaves as well as the midribs of the leaves can be used for basket weaving and inlay work in furniture.
In Indonesia, starch can also be extracted from sugar palms and used in place of rice flour in noodles, cakes and other dishes.
The seeds can be boiled and the stem tips can be eaten as a vegetable. The young flower stems can be crushed to get the juice.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/42096436/original.jpg
– http://plantillustrations.org/illustration.php?id_illustration=62418&SID=5j4c1du2bohn14dimhtf7bncs4&mobile=0&code_category_taxon=1

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.