plants text index | photo index
coastal plants
Rhu or Casuarina tree
Casuarina equisetifolia

updated Oct 2016
Where seen? This tree with delicate needle-like twigs and distinctive cones is commonly grown on our seaside parks. It is also often seen growing wild on our shores. According to Hsuan Keng, these trees were probably wild originally between Tanjung Rhu and Changi. Tanjung Rhu has since been reclaimed and the East Coast Highway now lies on the the reclaimed land. According to Giersen, it is found on sandy or rocky beaches and back mangroves. According to Burkill, the tree "demands sandy shores and is limited in a wild condition in Malaya" but planted extensively. According to Giersen, it is common on sandy coasts, low dunes and sandy mangroves. Originally from India, the Pacific Islands, northeastern Australia and throughout Southeast Asia. They have also be introduced in many other countries.

According to Corners, the seeds sprout in hot, open sand above the high-water mark and the young plants grow quickly, often form a thicket that eventually forms a Casuarina forest. The plants cannot settle under shade and thus form only on sandy shores that are advancing into the sea. In a suitable spot, the tree grows rapidly. The tree is also often planted inland, not so much for its shade but more as a wind break. "While the wind may blow hats off on the shore", behind a depth of three Casuarina trees, the air is "still and heavy". This is attributed to the fine twigs that break the wind.

At first sight mistaken for a conifer (a non-flowering plant), this tree is actually a flowering plant. While the pine-needles of a conifer are true leaves, those of the Casuarina are merely twigs, with the leaves reduced to tiny teeth.

The most common species is Casuarina equisetifolia (which some say should be called C. littorea) which has narrow, unbranched needle twigs, while the other species have branched or thicker twigs.

Features: Large tree up to 50m tall with a girth up to 3m. Bark brown, ridged and fissured, flaky in oblong pieces. The Casuarina also harbours nitrogen fixing bacteria in nodules in its roots, thus allowing it to grow in apparently infertile areas.

Leaves are reduced to tiny, pointed scales arranged in whorls of 6-10 at the joints of twigs. The 'needle-twigs' are greenish and photosynthesis takes place in these twigs instead of the tiny leaves.

The flowers are tiny and wind pollinated. Male and female flowers usually grow on separate trees. The tiny male flowers appear on short spikes (1.5-3cm long). Female flowers appear as pink fluffy bits on a short stalk. These turn into green cones. When ripe, the cones turn brown and the bracts on the cone open up, releasing small winged nuts. The cones are dispersed by water.

Human uses: According to Burkill, the tree was planted where it was desired to allow the soil to dry, as well as to check erosion and to fix drifting sand. It was also planted in India as firewood. Some consider it the best firewood as it will burn even when green. The timber is stronger than teak but splits much. It is sometimes used for beams and rafters, as well as for masts and other heavy duty uses. The bark is used to treat dysentery and diarrhoea, the twigs to treat swellings. According to Giersen, the heavy hard timber makes excellent firewood and charcoal and is sometimes used as beams. The bark yields a resin that is useful for tanning.

Pulau Semakau, Mar 09

Growing on rocky shore.
St. John's Island, Aug 09

True leaves reduced to tiny scales.
Pulau Semakau, Mar 09

Young fruit.
Pulau Semakau, Mar 09

Female flowers.
Pulau Semakau, Mar 09

Male flowers.
Pulau Semakau, Mar 09

Pulau Semakau, Mar 09

Fallen fruit, split open to release seeds.
Pulau Semakau, Mar 09

Casuarina trees on Singapore shores

Photos of Casuarina trees for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map


  • Casuarina equisetifolia on Total Vascular Flora of Singapore Online: photos and fact sheet.
  • Casuarina equisetifolia on the NParks Flora and Fauna website: photos and fact sheet.
  • Giesen, Wim and Stephan Wulffraat, Max Zieren and Liesbeth Scholten. 2006. Mangrove Guidebook for Southeast Asia (PDF online downloadable). RAP publication 2006/07 Food and Agriculture Organization of the United Nations Regional Office for Asia and the Pacific Bangkok.
  • Tanjung Rhu Road on infopedia on the National Library website.


  • Hsuan Keng, S.C. Chin and H. T. W. Tan. 1990, The Concise Flora of Singapore: Gymnosperms and Dicotyledons. Singapore University Press. 222 pp.
  • Tee Swee Ping and Wee Mei Lynn (eds). 2001. Trees of our Garden City. National Parks Board. 202 pp.
  • Wee Yeow Chin. 1992. A Guide to Medicinal Plants. The Singapore Science Centre. 160pp
  • Corners, E. J. H., 1997. Wayside Trees of Malaya: in two volumes. Fourth edition, Malayan Nature Society, Kuala Lumpur. Volume 1: 1-476 pp, plates 1-38; volume 2: 477-861 pp., plates 139-236.
  • Burkill, I. H., 1993. A Dictionary of the Economic Products of the Malay Peninsula. 3rd printing. Publication Unit, Ministry of Agriculture, Malaysia, Kuala Lumpur. Volume 1: 1-1240; volume 2: 1241-2444.
FREE photos of coastal plants. Make your own badge here.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008