T CLIMB THE TREE?
KENYA: WHISTLING THORN
THE whistling thorn is common throughout the savannah landscape of eastern Africa.
From a distance, it is an unremarkable shrubby tree, growing
COSTA RICA: SANDBOX
THROUGHOUT tropical Central and South America and parts of the Caribbean, Hura crepitans is known by many names including monkey-no-climb, poison tree, dynamite tree and sandbox. Each one highlights a different aspect of this dangerous tree.
The trunk, which can easily reach over 165ft tall, discourages casual contact. Every inch is well-armoured by stubby, razor-sharp thorns. Its caustic, milky-white sap deters almost anything that might consider eating its leaves.
But what really sets this tree apart is the astonishing way it disperses its seeds.
Most plants dispatch seeds by making them light enough to carry in the breeze.The seeds of the sandbox, on the other hand, must germinate in the gloom of the forest floor so they must travel with the nutrients they will require.
These seeds are held inside seed pods in the shape of a peeled tangerine with about 16 segments.As they lose moisture, some parts dry out and shrink faster than others.
Enormous tension builds up until there is a sudden release, usually on a hot, dry day, and the pod explodes.
The seeds are jettisoned with a huge bang at more than 230ft per second – 150 miles per hour – which helps them to fly nearly 150ft, far enough to ensure seedlings do not compete with their parent.
MADAGASCAR:
LARGER than France, the island of Madagascar is a dream destination for naturalists.
It has been isolated from the rest of Africa for 150 million years and from India for 90 million years. So almost all the native plants are endemic (they do not exist naturally anywhere else in the world).
The island’s iconic traveller’s tree, known locally as fontsy, is half-glorious, half-ridiculous and totally spectacular.
It forms a huge fan on one vertical plane, an enormous and improbably symmetrical arrangement of paddle-shaped leaves, each up to 10ft long and 18in wide.
Its name is said to originate from the fact the arc of foliage always faces a certain direction, although it is hard to pin down if this is true. Another reason is that rain is channelled down the interlocking U-shaped leaves into the centre of the tree, which can accumulate up to two pints of water. It gets brackish, doubtless with all manner of wriggling things. But it is possible to insert a tube into the stem and drink direct. to about 20ft tall. However, on a breezy day it makes a discordant, high-pitched whistling noise.
At the base of every leaf cluster, is a pair of straight white spines, each as long as an adult’s finger, to ward off many herbivores. If you venture closer, many have bulbous, hollow bases, the size of a walnut.
Small holes cause the whistling as air flows past them. But what are they for? Tap the tree a few times and hundreds of ants come rushing out to set upon intruders.