Hopea odorata

Common name: Thingan

Other common names: Merawan, White thingan

Names in non-English languages: Malaysia Thailand

Description

Thingan is a timber and landscape tree native to tropical India and Southeast Asia, its natural range extending from Sri Lanka to the Andaman and Nicobar islands, and from Bangladesh to Myanmar (Burma), Thailand, Malaysia and Indochina.

It is a large tree and may reach heights of up to 45 m (148 ft) in natural forests, with a straight trunk of about 1.2 m (4 ft) diameter and with buttresses on mature trees. On open sites, it is more typically 25 to 30 m (82 to 98 ft) tall with gently ascending branches forming a pyramidal crown, becoming more rounded as the tree ages. The bark is light- to dark-brown and roughened by vertical fissures and ridges.

Leaves oval, 10 to 15 cm (4 to 6 in) long, dark green and alternately arranged along the ends of the branches. They remain on the tree in all seasons.

Flowers white, small and held in branched clusters arising at the sides and ends of the branches. They bloom only every second spring and are followed by small egg-shaped nuts around 1 cm (0.4 in) long, appendaged with a pair of long blade-like wings. The nut and wings are green when young, becoming brown when mature, then detach to fall and glide on the wind.


Large tree (Singapore Botanic Gardens)

Use

The tree produces a wood grouped with other Hopea species under the commercial name 'Merawan', which has heartwood that is yellowish-brown darkening to olive-brown on exposure. It is lightweight to heavy, in the 500 to 950 kg per cubic meter (31 to 59 lbs per cubic ft) range, and has variable natural resistance to rot and decay, ranging from non-resistant to very resistant.

Variability in the weight and natural resistance of the wood is most probably due to differences in the wood properties between the different Hopea species, as well as differences in tree growth rates.

Well-formed logs are sawn into boards and planks used mainly for furniture and cabinets, flooring and decking, interior joinery and millwork.

The trunk yields without wounding a hard, yellow, whitish or colourless resin that is soluble in turpentine. It is sometimes used as a varnish-over-paint, though it is reportedly somewhat inferior to better-known and more widely used varnish resins.

Thingan is commonly grown in its native range as a street and landscape tree for its shapely and stately form, as well as for the shade it gives.

Unrestricted logging in its native range has led to a decline in natural populations. It is recorded as a vulnerable tree species by the International Union for Conservation of Nature and Natural Resources (IUCN), which brings attention to its conservation needs.


Trees providing shade in an urban park (Ho Chi Minh City, Vietnam)


Trees used as a street tree (Ho Chi Minh City, Vietnam)

Health use

The resin exude in its powdered form is used in traditional medicine in Myanmar (Burma) as a styptic, with action that helps to halt bleeding when applied to wounds.

Climate

Grows naturally in humid to very humid tropical lowland climates, generally areas with annual lows of 19 to 25 °C, annual highs of 27 to 35 °C, annual rainfall of 1700 to 5000 mm and a dry season of 5 months or less.

Although it also grows naturally in seasonally dry areas with annual rainfall as low as 1200 mm, the trees are usually found close to rivers, stream and watercourses where the roots have access to groundwater during dry periods.

How to grow

New plants are started from cuttings or seed, which lose their viability quickly, even under storage and are best sown within one to two weeks of harvesting the nuts. The seedlings are nursed under fifty percent shade until they are about 50 cm (1.6 ft) tall, at which point they can be planted out.

Performs best on slow- to free-draining clay-loam, loam and sandy-loam soils of an acid to neutral nature, generally with a pH of 4.5 to 7.5 and on sites with full to partial sun exposure.

Problem features

Despite its wide distribution, there does not appear to be any record of it being a weed or invasive species. The nuts, though they can be dispersed far by the wind, lose their viability quickly and are reportedly highly susceptible to attack by weevils after they have landed on the forest floor. It unlikely to emerge as a problem weed or invasive species.

Where it will grow

With irrigation or groundwater

References

Books

  • C.A.B. International 2013, The CABI encyclopedia of forest trees, CABI Publishing, Wallingford, Oxfordshire

  • Do, D. S. & Nguyen, H. N. 2003, Use of indigenous tree species in reforestation in Vietnam, Agricultural Publishing House, Hanoi

  • Howes, F. N. 1949, Vegetable gums and resins, Chronica Botanica Company, Waltham, Massachusetts

  • Kraemer, J. H. 1945, Native woods for construction purposes in the South China sea region, Bureau of Yards and Docks, Navy Department, Washington D.C.

  • Letourneux, C. 1957, Tree planting practices in tropical Asia, Food and Agriculture Organization of the United Nations (FAO), Rome

  • Scheffer, T. C & Morrell, J. J. 1998, Natural durability of wood : a worldwide checklist of species, Forest Research Laboratory, Oregon State University, Corvallis, Oregon

  • Troup, R.S. & Joshi, H. B. 1975 to 1981, Silviculture of Indian Trees (3 volumes), Government of India Publications, New Delhi

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