For some people, the mention of “sun, sea and sand” calls to mind a clear blue sea and a beach fringed by coconut fronds. For others, it evokes having a picnic or lazing the day away by the sea under the shade of a casuarina tree. The truth is that the former is a sight common only in travel brochures; from Rayong in the East down to Phuket in the South, it is Casuarina equisetifolia, commonly known as ironwood or horsetail casuarina (son talay in Thai) that is an integral part of Thai coastal areas. There are more casuarinas on Thai beaches than coconuts.
lock it in: The casuarina’s extensive network of roots prevents soil erosion.
Casuarina equisetifolia is a tall tree, growing up to 30-40m. Known simply as casuarina, it is moderately fast-growing but although its foliage makes it a beautiful ornamental tree, it is planted extensively along coastal areas for other reasons too. An evergreen tree, it is salt and drought resistant; it has a massive trunk and strong, hard wood, thus it makes a formidable windbreak; and it has an extensive network of roots that is very effective as a sand-dune stabiliser and for preventing coastal erosion.
Casuarina has been close to my heart since I was a child. By the middle of December in the years I was in grade school, boys in our class would cut the best branch from the row of casuarina, known in the Philippines as agoho, growing on a river bank. This we would decorate as a Christmas tree, and hang gifts on it for our Christmas party. As a young bride I came to Thailand and lived in a house with a wooden fence lined by tall casuarina trees, and for my first trip to the seaside I was taken to Had Chao Samran in Phetchaburi, where I swam in the sea bordered by gigantic casuarinas. Before Jomtien near Pattaya was turned into a resort strip, it was a quiet, isolated place with casuarina trees forming a narrow belt along the beach. When my children were little we loved nothing more than having a Sunday picnic there in complete privacy under a casuarina tree. Or we would go further down the road to Laem Mae Phim in Rayong, which, in the minds of most Thais, is synonymous with casuarina. Now that I have a grandson, our favourite holiday destination is Prachuab Khiri Khan, where he can frolic on the shallow waters and sandy beach at Ao Manao, while in the distance the branches of lofty casuarina trees whistle as the wind blows.
Despite its needle-like leaves, cone-like fruit and resemblance to a conifer or pine tree, casuarina is not related to the Pinaceae, or pine, family of plants. It belongs to the Casuarinaceae family, whose members are either monoecious or dioecious. Monoecious plants have separate male and female flowers on the same plant, while dioecious plants have male flowers on one plant and female flowers on another plant, hence several female plants should be planted with a male plant for fruit production. Casuarina trees can be either monoecious or dioecious; the elongated male inflorescence are located near the ends of the upper branches, and pollinate the globose female inflorescence on the lower branches or in axils by releasing pollens. Like the pineapple, the casuarina fruit is compound: that is, it comprises several fruits fused together as one.
Casuarina equisetifolia is often mistaken for its cousin, Casuarina junghuniana, known in Thai as son pratipat. The latter is a straight tree with no crooked side branches like the former. What’s more, its branches are relatively smaller. Named after Phraya Pratipatphubarn, who reportedly brought it into the country, it is a classic example of a dioecious tree. The trees found in Thailand bear flowers but they are all male, and thus produce no fruits or seeds. The tree is propagated only vegetatively, that is, by stem cutting or layering. It is therefore safe to say that all the son pratipat in the country are descendants of the same tree brought into the country more than a century ago. What escapes me is why, over the years, no one has thought of bringing in a female tree.
Casuarina equisetifolia can be propagated vegetatively by using cuttings 3-4cm in diameter and 30-35cm in length. In the Philippines, India and Sri Lanka, it is also propagated by seed for reafforestation purposes. Researchers from the Ecosystems Research and Development Bureau at the University of the Philippines in Laguna report that seeds take 150 days from sowing to attain the ideal plantable size of 30-40cm.
The soil must be well-watered before sowing to allow the winged seeds to stick to the soil surface. A thin layer of soil is then sprinkled to cover the seeds. Watering is done using a hose with fine spray twice a day for the first 15 days and once a day thereafter. In 10 days, seedlings about 10-15cm high are ready to be transplanted in individual black polyethelene bags and watered once every two days until these are ready for the open field.
Casuarina wood is heavy and hard, and used to make tool handles and as posts, poles and pilings. The wood burns even when green, providing excellent firewood and charcoal. Because of its high tannin content, the bark has medicinal uses. According to the book Beach Forest Species and Mangrove Associates in the Philippines, bark infusions are used as a remedy for mouth and throat infections, asthma, diabetes, urinary tract infections and stomach ache; while bark/root decoctions are used to treat colic, dysentery, diarrhoea, beriberi, and as an astringent and to sedate mental patients. However, as I found out from the trees that lined my in-laws’ fence, it is not advisable to plant the tree in your garden, as fallen needles inhibit the growth of other plants. n
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Summer Daze: For many Thais, ‘sun, sea and sand’ means having a picnic or lazing the day away by the sea under the shade of casuarina trees.
