Baobabs, Part Three, Symbiosis

photograph by Cheryl Merrill

photograph by Cheryl Merrill

Found mostly in seasonally arid areas, baobabs grow very slowly as they age, except for first years of its life, when a baobab grows relatively quickly.  A tree planted in Kruger National Park in South Africa grew 65 feet tall with an eleven-foot diameter in just 38 years.  In contrast, an older tree described by Livingstone in 1858 grew only two feet in circumference in 110 years.  Despite their early exuberance, baobabs can be cultivated as bonsai trees.

Young baobabs have only single leaves per stem. Without their crooked branches and five-leafed stems, they are difficult to recognize. Kalahari Bushmen believe the trees appear fully-grown, planted upside down by the gods, with the tree’s roots in the air. They also believe spirits inhabit the baobab’s large, waxy-white flowers, and if anyone has the audacity to pick one, they will be eaten by a lion. The flowers open just before dark, produce copious amounts of nectar and last for only 24 hours. Their heavy, carrion-like scent attracts nocturnal insects and bats, such as the Epaulleted fruit bat. The Kalahari Bushmen are right: the smell of a freshly-picked baobab flower behind your ear would make you bait for lions drawn to the carrion scent.

Older baobabs have a tendency to rot out their heartwood, but completely heal around the hollowed trunk. Rats and reptiles frequently invade them and African honeybees often establish hives in crevices of a baobab. Native to central and southern Africa the bees are actually a subspecies of the Western honeybee. A single sting from an African bee is no more venomous than a single European or American bee sting, but African honeybees respond more quickly when disturbed and send out three to four times as many workers in response to a threat. They also pursue an intruder for a greater distance from the hive – thus their reputation as “killer” bees.”

Physically unable to break open a beehive, the Honeyguide has developed a symbiotic relationship with humans, letting another species take the risk of being swarmed. A Honeyguide indicates the presence of a hive by continuously dive-bombing nearby, all the while uttering monotonous, squirrel-like chirps. Alerted by the Honeyguide, intrepid Kalahari Bushmen pound pegs into the soft bark of baobabs to climb the tree, lull the bees with smoke and obtain a sweet reward for taking that risk. Bushmen always leave honey for the birds, for if they should fail to do so, the Honeyguide will one day lead them to a lion, instead of a hive.

“Pachycaul” is a scientific term used to describe a variety of thick-stemmed plants with few branches. “Pachy” is Greek for “large” and “caul” is Latin for “trunk.” Pachyderm is a term for describing large, thick-skinned animals such as elephants. In times of drought, elephants strip the bark of the baobab and eat the spongy wood underneath, estimated to contain 40-70% water – which classifies the baobab as the world’s largest succulent. An individual baobab can store up to 32,000 gallons of water.  When pachyderms meet pachycauls, it is the baobab that suffers. Sometimes, during these times of drought, elephants will completely gird a tree, leaving it standing as if on its own pedestal, and yet the baobab will still survive.

Weighted with water, baobabs barely move in the wind. Even a mild frost will kill a baobab, so they are never found at elevations over 3,000 feet. The tree is also sensitive to both flood and extended periods of drought. In Madagascar, a sugar mill diverted water onto land containing baobabs, which subsequently stood in water year-round. The trees began to rot and topple over until the land was drained and the remaining 313 baobabs upon it were declared part of a conservancy area.   A highway constructed near the Nomslang Baobab in South Africa brought thousands of visitors to marvel at its size. Unfortunately, their feet trampled the earth beneath it into hardpan, making the ground impervious to rainwater and the famous baobab died. Baobabs melt into a huge, fibrous mass within a few months after their death, leaving behind mounds of stinking pulp and a pit filled with a rotting taproot. Soft spots around dead baobabs also indicate locations of its root system, which may radiate just below the surface for 300 to 1300 feet.

Some species of plants and trees emit chemical signals when under attack. I wonder if the baobab talks to its long-lived kin as it dies. Baobabs live up to two thousand years, 730,000 revolutions of daylight and darkness. Perhaps its chemical whisper is Patience, perhaps it is Eternity, perhaps it is Dream.

 

 

The most comprehensive book ever written about baobabs is The Baobabs: Pachycauls of Africa, Madagascar & Australia, Gerald Wilkins and Pat Lowe

 

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