This is undoubtedly the narrowest tree in the collection. Here is a great Asian river which, like many others, originates in the snow-capped mountains of High Mountain Asia and plunges its roots into the warm waters of the tropics, much like a neighbouring tree, the Ganges. The Khmer people saw in the Mekong a counterpart to the Ganges and began to call it Ma Ganga, Mother Ganges—an honorific name given by Khmer Hindus to a river they regarded as no less than an equal to the holy Ganges. The influence of ancient India was so strong at the time that it crossed seas and mountains, connecting two great trees together.

The river has other local names, like the “river of nine dragons” in Vietnamese, because of its nine-branched estuary. Discharge wise, the Mekong is the fourth among Asian rivers despite its narrow surface area: it is truly a tropical tree!

While the structure of this tree is reminiscent of the Nile, the tall and slender Phoenix Nilus, its geography is quite different: its source is in China, in the cold mountains of Qinghai, where the river bears the beautiful name Lancang, meaning “turbulent.” The Mekong river tree is so high, stretching 4,350 kilometers, that it is not surprising that it encounters turbulence at this altitude.

The river's waters only find some respite when they leave China, where the riverbed is only 500 meters above sea level, compared to more than 5,000 meters at its source. It is in this region, halfway up, that the Mekong forms the lower part of the tree, where most of the 70 million inhabitants live, at the crossroads of the branches coming from left and right, from Laos, Vietnam, Thailand, and Cambodia.

Like the Amazon River, it is a safe haven for biodiversity, boasting the world’s second highest density of animal and plant species within its branches. For example, it is home to the Irrawaddy dolphin, an endangered freshwater dolphin, and the giant Mekong catfish, traditionally fished by the Thai royal family once a year!

If rivers were classified according to their ability to unite or divide peoples, the Mekong would perhaps fall into the second category: with its numerous waterfalls and therefore poor navigability, the river has been seen throughout history as more of an obstacle than a bridge. A tree with branches that are too fragile, or perhaps thorny? For a botanist studying the rings of the Mekong's trunk, traces of the splendid Khmer Empire (8th-15th century) would undoubtedly appear, but so would those of the European and American crimes of the 20th century, which have left visible marks on the tree, literally: quantities of American explosives continue to this day to be recovered from the river waters to defuse serious accidents.

The Mekong reminds me of the sugar palm, Arenga pinnata, a tree native to the Mekong region with a very similar slender shape and famous for the palm wine made from it, an aromatic and sweet drink popular in Southeast Asia. Another distinctive feature reminds me of that tree: the trunk of Arenga pinnata is thorny, like the river's waterfalls preventing navigation to the top of the tree...

The Mekong palm tree, Arenga Mekongensis