Kamikaze tree has key to survival

XAVIER METZ, a Frenchman, runs a cashew farm in Madagascar. While he and his family were walking in a remote area of the country last year, they came upon a strange-looking palm tree with its branches covered in flowers.

They took photographs of the tree which John Dransfield of London’s Kew Gardens saw on the web.

Dransfield, an authority on palm trees and the author of The Field Guide to the Palms of Madagascar, was astonished. It was not like any tree he knew. A botanist in Madagascar was asked for tissue samples. These were sent to Kew for DNA analysis. The results were astonishing; the tree was new to science.

Between one and two million species of animal and plant have been “described”, but nobody knows how many there are in the world. Newly discovered plants tend to be small and inconspicuous. That something as prominent as a large tree should have remained undetected until now is extraordinary. But the newly discovered palm is not just big; it’s an 18-metre-high giant.

The leaves are five metres long, large enough to show up on satellite photographs. Ninety-two trees have been counted to date. The oldest are thought to be about a hundred years old.

The name chosen for the palm has been announced in the latest edition of the Botanical Journal of the Linnean Society. The tree is so different from other palms that a new genus, known as Tahina, has been created. Anne-Tahina Metz is the daughter of Xavier. The name means “blessed” or “to be protected” in Malagasy. The species name spectabilis means “remarkable”. It’s an appropriate choice; when the tree flowers, its appearance is dramatic. Having grown for 80 to 100 years, a long shoot appears at its top.

This becomes an inflorescence and hundreds of flowers appear along its branches. Insects and birds flock to feed on the dripping nectar. The pollinated flowers develop into fruit.

Then an extraordinary thing happens; once it has shed its fruit, the tree dies. It commits suicide, sacrificing itself for its offspring. So much resources are put into the effort to produce seeds that it hasn’t the strength to go on. But the tree’s sudden demise may help its youngsters. Its absence could create space for the little trees to grow and reduce the competition for light and resources.

But shedding all its seeds in one season seems a risky strategy. An unexpected shortage of pollinators, or prolonged periods of freak weather during the crucial period, could mean that a hundred years of growing have been in vain.

It’s not a good idea for any creature to put all of its eggs in one basket.

The tree has distant relatives living in Arabia, Iran and Thailand, thousands of kilometres away. Africa and India were once part of the same huge landmass but, in the great rupture of continents which began 225 million years ago, they separated.

Madagascar broke away from Africa, becoming an island in the expanding Indian Ocean.

During the aeons of isolation, its animals and plants developed Malagasy solutions to Malagasy problems, becoming, in the process, unlike those found anywhere else. About 90% of Madagascar’s 10,000 plant species occur nowhere else in the world.

Of the world’s 2,800 species of palm, 170 are found in Madagascar, all but six of them endemic.

But all is not well in Madagascar. Forests are being cleared, alien species have been introduced and climate change is affecting the ecosystem. Only one fifth of the original vegetation remains.

The new tree will need protection if it is to survive. However, its extraordinary life-style may be its salvation. Tahina spectabilis is fast becoming famous; arboreta and botanic gardens everywhere will want specimens to grow.

This will give local people an incentive to protect their extraordinary palm. Another tree is expected to flower next year and the locals will be able to sell its seeds to gardeners around the world.

Ironically, the tree’s self-destructive kamikaze behaviour may ensure its survival.

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