We were in the grounds of the seaside Marriott hotel in Rayong during a family holiday recently. I was walking towards the beach, with my husband, ML Charuphant, following several steps behind, when he called out.
Always the one with sharp eyes where plants are concerned, he asked: “Did you see the difference between these two trees?”
I stopped and walked back. Only two metres apart, the two trees in question were apparently of the same age and planted at the same time. About three to five years old, they were of the same height, and except for the fact that one had more sprawling branches than the other, they looked the same, with pinnate leaves that were very much alike.
But wait. The one with sprawling branches had dark greyish-brown, fissured bark, while the other had a smooth, golden trunk. Then it dawned on me: They were of the same genus, but different species.
The one with fissured bark is a common sight in Thailand. Native to Central and South America — from the Yucatan Peninsula in Mexico, through Guatemala to Peru, Bolivia and Brazil — it was introduced to this country, probably via Singapore, in the latter part of the 1800s, during the reign of King Chulalongkorn (King Rama V).
It was known as Enterolobium saman until botanists moved it to a genus of its own, Samanea. But even this later became obsolete, and the former Samanea saman is now known by the name Albizia saman. To Thais the name remained the same: Chamchuri, also sometimes spelled jamjuree, which Chulalongkorn University adopted as its symbol.
The other tree, Albizia lebbeck, is native to Indo-Malaya, New Guinea and northern Australia. Some plant enthusiasts believe it to have come to Thailand via Australia, but there are those who think it is also indigenous to this country but called by another name. It, too, has a convoluted taxonomic history, having been variously called Mimosa lebbeck, Acacia speciosa, Mimosa speciosa and Albizia latifolia. Thais call it chamchuri-thong, the golden chamchuri.
But what is in a name? No matter what they are called, both are fast-growing shade trees that help improve the ecology and the balance of nature. I have not observed closely how Albizia lebbeck behaves, but Albizia saman folds its leaves at nightfall or when the sky is overcast because of impending rain, allowing the rain to pass through easily. It is probably because of this that it is commonly called a raintree. This name is said to have also come from its habit of intermittently spraying the ground underneath with moisture. It was found that the moisture was in fact secretion by lac insects, which love to make the tree their home.
In the commemorative book Nai Lert Park, author William Warren relates how business entrepreneur Lert Sreshthaputra, simply known as Nai Lert, bought large tracks of land in the Phloenchit area in 1915, laid out streets, planted them with raintrees, then sold them as individual plots. The largest, covering 32 rai, was purchased by the British government in 1921 as the location for a new embassy.
By the time I arrived in Thailand in 1969, the trees Nai Lert planted had grown into sprawling giants that shaded the entire block where Central Chitlom and Central Embassy shopping centres now stand. Huge raintrees also occupied vacant lots on Wireless Road, where only the American embassy, the Netherlands embassy and a few other buildings then stood.
With Bangkok’s modernisation and increase in population, most of the trees have been cleared for the construction of high-rises and commercial buildings. Samples, however, can still be seen in the grounds of the American embassy residence, the Netherlands embassy and the British embassy, as well as at the Swissotel Nai Lert Park Bangkok, which is built on the land Nai Lert set aside for his own use but which now belongs to his heirs.
Our world is getting hotter every year. The World Meteorological Organisation, US National Oceanic and Atmospheric Administration, Nasa and Japan’s weather agency all agree that the past year was the hottest on record, surpassing 2014’s record heat. And unless you live in an air-conditioned house, jump into your air-conditioned car to work in an air-conditioned office, you must have noticed that the heat of summer has now descended upon us in Bangkok — and it’s only the middle of January.
Growing rapidly, raintrees — both the fissured and the golden varieties — are the trees to plant if we want a cooler and cleaner environment. Researchers at the Bogor Agricultural Institute’s School of Forestry in Indonesia found that a mature raintree with a crown diameter of 15 metres absorbed 28.5 tons of carbon dioxide annually.
Seeds germinate easily, and grown on each side of the road, the trees’ branches spread out to form a green canopy for motorists. Used to cover denuded hills and unused land, they serve as pioneer trees that attract birds, monkeys, squirrels and other wildlife, which feed on fleshy pods containing sweetish pulp. Fallen leaves enrich the ground, nourishing other plants growing under their canopy.
Raintrees are a haven not only for wildlife, but for other plants as well. In places where humidity is high, as in Phuket, it is not uncommon to see different species of ferns and orchids growing on the branches of mature trees. They can be grown in any type of soil, but thrive best in good soil with enough water during their growing period. If regular watering cannot be provided, as in reafforestation areas, it is advisable to do the planting in the rainy season. The trees must be at least 10 metres apart, to provide space for their large crown.
Despite the cool breeze from the sea, Rayong is hot even in the morning sun. The Marriott hotel has a sprawling ground and could do with more raintrees to provide shade for guests as they stroll around the property. Rich in nitrogen, fallen leaves make a wonderful material as mulch or as humus to enrich the soil for other plants.
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