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Shorea sumatrana (Slooten ex Thorenaar) Desch

Family Name:	Dipterocarpaceae
Synonyms:	Isoptera sumatrana Slooten ex Thorenaar, Isoptera borneensis auct. non Scheff. ex Burck: King & Gamble
Common Name:	Sengkawang, Balau Sengkawang Air, Kedawang

Shorea sumatrana, also known as Sengkawang is a critically endangered tree in Singapore. Growing up to 30 m tall, it has woody fruit, each with five orbicular calyx lobes. It produces Balau timber, a heavy hardwood that is prized regionally for heavy construction.

Full Sun

Moderate Water

Native to Singapore

Tree

Name

Family Name
Genus Epithet
Species Epithet
Name Authority
Name Status (botanical)
Synonyms
Common Names
Comments
Species Summary

Classifications and Characteristics

Plant Division	Angiosperms (Flowering Seed Plants)
Plant Growth Form	Tree
Lifespan (in Singapore)	Perennial

Mode of Nutrition	Autotrophic
Plant Shape	Broad / Mushroom / Hemispherical
Maximum Height	30 m

Biogeography

Native Distribution	Thailand, Peninsular Malaysia, Singapore and Sumatra
Native Habitat	Terrestrial
Preferred Climate Zone	Tropical

Local Conservation Status

Native to Singapore (Critically Endangered (CR))

Description and Ethnobotany

Growth Form	It is a tree, up to 30 m tall with buttresses. Bark is smooth with many lenticels when young, and gradually becoming scaly with age. Stipule is lanceolate (7 mm long) and falls off early.
Foliage	Leaves are green, papery to thinly leathery and arranged alternately. Each leaf is elliptic to ovate shaped (7 – 14 cm long and 4 – 7 cm wide). The leaf base is blunt to wedge shaped while leaf tip is tapering (0.6 – 1.2 cm long). The upper surface of the leaf is glabrous while the lower surface is scaly (lepidote) or glabrous. Each leaf has 9 – 12 pairs of secondary veins. Both the midrib and secondary veins are sunken above and visible and prominent below. The petiole is slender (1.1 – 1.7 cm long) and sparsely covered with soft hairs.
Flowers	Flowers occur in a cluster as a panicle inflorescence at the terminal or axillary position. Inflorescence is single-branched, reaching up to 10 cm long, and comprises of up to 6 flowers. All the flowers on the branch face the same direction (secund). Flower is small, creamy white to pale yellow with pink tinge at base of the petal. The petals are glabrous on the inside while hairy on the outside. Each flower has 22 – 27 stamens with oblong anthers tipped by bristly appendages slightly shorter than anther. The ovary is densely hairy, conical to hourglass-shaped with short smooth style.

Fruit	The fruit is woody and covered with soft hairs. Each fruit has 5 orbicular calyx lobes (0-8 – 1.1 cm long and 0.9 – 1.2 cm wide). These calyx lobes are almost equal sized. The orbicular calyx lobe is a key feature to identify Shorea sumatrana. The nut is globose (1.1 – 1.4 cm diameter) with a short tip.
Habitat	It is found in swamp forests, and lowland dipterocarp forest, near river bank.
Similar	Shorea seminis is very similar to Shorea sumatrana. S. seminis occurs from Borneo and the Philippines, while Shorea sumatrana occurs in Thailand, Peninsular Malaysia, Singapore and Sumatra.
Associated Fauna	Flowers are pollinated by insects.
Cultivation	It can be propagated by seed.
Etymology	Latin Shorea, commemorating Sir John Shore (1793-1798), the Governor-General for the British East India Company; Latin sumatrana, refers to Sumatra, one of the places where it occurs naturally.
Ethnobotanical Uses	Timber & Products: it produces Balau timber, a heavy hardwood that is prized regionally for heavy construction, such as bridges, railway sleepers, powerline posts, wagons and fence posts. Others: One mature individual was found in Singapore Botanic Gardens’ Jungle and estimated to be 167 years old.

Landscaping Features

Landscape Uses	Reforestation, Parks & Gardens

Plant Care and Propagation

Light Preference	Full Sun
Water Preference	Moderate Water
Plant Growth Rate	Slow

Rootzone Tolerance

Well-Drained Soils, Moist Soils

Foliar

Foliage Retention	Evergreen
Mature Foliage Colour(s)	Green
Mature Foliage Texture(s)	Leathery, Papery

Foliar Type	Simple / Unifoliate
Foliar Arrangement Along Stem	Alternate
Foliar Attachment to Stem	Petiolate
Foliar Shape(s)	Non-Palm Foliage (Elliptical, Ovate)
Foliar Venation	Pinnate / Net
Foliar Margin	Entire
Foliar Apex - Tip	Acuminate
Foliar Base	Rounded / Obtuse, Cuneate
Leaf Area Index (LAI) for Green Plot Ratio	2.5 (Tree - Open Canopy)

Non - Foliar and Storage

Trunk Type (Non Palm)	Woody
Mature Bark Texture	Scaly
Stem Type & Modification	Woody

Root Type

Underground

Floral (Angiosperm)

Flower & Plant Sexuality	Bisexual Flowers , Bisexual Flowers
Flower Colour(s)	Cream / Off-White

Flower Grouping	Cluster / Inflorescence
Flower Location	Axillary, Terminal
Flower Symmetry	Radial
Individual Flower Shape	Saucer-shaped
Inflorescence Type	Panicle
Flowering Period	Every Few Years
Flowering Habit	Polycarpic

Fruit, Seed and Spore

Mature Fruit Colour(s)	Brown
Mature Fruit Texture(s)	Hairy / Hirsute
Fruit Classification	Simple Fruit

Fruit Type	Indehiscent Dry Fruit , Samara
Seed Quantity Per Fruit	Few (1-5)

References

References	Ashton, P.S. (1982). Dipterocarpaceae. In: van Steenis, C.G.G.J. (ed.) Flora Malesiana, ser.1, vol. 9, part 2, pp. 237–552, 575–600. The Hague/Boston/London: Martinus Nijhoff/Dr. W. Junk Publishers. Ganesan, S.K. & Ali Ibrahim (2018). Shorea sumatrana (Dipterocarpaceae), a remarkable new addition to the flora of Singapore. Gardens’ Bulletin Singapore 70: 261–266. Pooma, R., Poopath, M. & Newman, M.F. (2017). Dipterocarpaceae. In: Santisuk, T. & Balsev, H. (eds) Flora of Thailand, vol. 13, part 4, pp. 557–685. Bangkok: The Forest Herbarium, Royal Forest Department.

References

Ashton, P.S. (1982). Dipterocarpaceae. In: van Steenis, C.G.G.J. (ed.) Flora Malesiana, ser.1, vol. 9, part 2, pp. 237–552, 575–600. The Hague/Boston/London: Martinus Nijhoff/Dr. W. Junk Publishers.

Ganesan, S.K. & Ali Ibrahim (2018). Shorea sumatrana (Dipterocarpaceae), a remarkable new addition to the flora of Singapore. Gardens’ Bulletin Singapore 70: 261–266.
Pooma, R., Poopath, M. & Newman, M.F. (2017). Dipterocarpaceae. In: Santisuk, T. & Balsev, H. (eds) Flora of Thailand, vol. 13, part 4, pp. 557–685. Bangkok: The Forest Herbarium, Royal Forest Department.

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Master ID	1835
Species ID	3128
Flora Disclaimer	The information in this website has been compiled from reliable sources, such as reference works on medicinal plants. It is not a substitute for medical advice or treatment and NParks does not purport to provide any medical advice. Readers should always consult his/her physician before using or consuming a plant for medicinal purposes.