Page 21 - The Villager August 2021

Nature

Three dozen botanists, led by South African a passing bird just before a once-in-a-decade
botanist Eugene Moll, claim the ruling goes rain shower enabling it to survive long enough
against the normal rules of the system devised to send down an exploratory root to seek
more than 200 years ago by the Swedish water. Its lacy, compound leaves would have
scientist, Carolus Linnaeus. The system, captured the droplets from the nightly mists
adhered to worldwide, gives a scientific name that roll in from the Atlantic and, before the
to all living organisms, alive and extinct. The relentless sun emerged, the droplets would
botanists (on our side) insist "the accepted have fallen like rain into the tree’s shade.
rule is that the earliest published name has During this time the tree’s bark will have lost its
precedence" and the first species named rich chestnut red colouring to become rough
‘Acacia’ was an African tree described in 1753. and grey. The bark, incidentally, has been used
Paradoxically, the spelling of the sweet for centuries for tanning leather.
thorn’s species name, which was, in error, spelt During a drilling operation in the dry west,
‘karroo’ cannot be corrected to the proper Mogg recalled workers hitting a sweet thorn’s
spelling, ‘karoo’ because of the system’s rules. tap root 120 feet (40 metres) down, measuring
But, as Shakespeare put it, “A rose by any an inch thick (25mm). He said it was wet and
other name would smell just as sweet,” and “smelt like a drain”.
Vachellia karroo remains just as sweet as ever. The sweet thorn’s contribution to
Its sweetness comes from the thick sap that human culture has been considerable. The
oozes from wounds in its trunk – it has been Witwatersrand University archaeologist,
used as a confection in Africa probably for as Prof Revil Mason, identified three Iron Age
long as humans have existed. It is still used foundries in Lonehill, and carbon dating found
today by confectioners. Many mammals, they were at least 800 years old. For more than
birds, reptiles and insects relish it including the six centuries iron was extracted from iron-
giant kori bustard whose name in Afrikaans is bearing pellets (ferricrete) that still crunch
gompou, meaning literally, ‘gum peacock’. underfoot – but the fuel for the furnaces?
Acacias, as botanists informally continue From where did that come? The surrounding
to call the genus, are found across the world Highveld is to all intents and purposes empty
including America. There are more than 1 000 of native trees yet to forge a single hoe blade
species in Australia and 300 elsewhere. or a spear would, said Mason, have needed
I recall the renowned botanist, Dr AOD charcoal from the trunks of two thorn trees
‘Bertie’ Mogg, with whom I travelled on many measuring 20cm in diameter at breast-height.
local botanical surveys in the 1970s, telling me It meant the original landscape of the Highveld
how the sweet thorn was rare along South must have been well wooded – an open forest
Africa’s eastern side, especially in eastern Natal, of spaced out acacias and karee trees. So it can
but that it was spreading. By the time Mogg be said that thorn trees fired our first step to
died in 1980, it had reached the Indian Ocean becoming a manufacturing nation.
and, in parts, was regarded as a troublesome Apart from its usefulness as fuel wood and
invasive species. Its spread was the result of for making charcoal, the sweet thorn was
injudicious veld burning (sweet thorn saplings used to make fence posts and ‘living fences’ by
are pretty much fireproof) and overgrazing, being grown as a thorny hedge.
which changed the nature of so much of South The sweet thorn’s inner bark was used to
Africa’s savannah, creating ideal conditions for make rope, and proved essential for making
the tree. barges to cross rivers and for wagon-making.
The presence of sweet thorn is an indicator For centuries, communities have viewed
of sweet veld whose soils are good for grazing a mature acacia – and many still do – as
as well as for crops. Hydrologists view its their local pharmacy. Its pods, leaves and
presence as an indication of ground water. roots are believed to be effective for making
A single acacia in the Namib Desert can concoctions to relieve pain, for the treatment
assume the importance of a geographical of open wounds, to relieve constipation,
location and be marked on maps; it might and as a remedy for diarrhoea, colic, malaria,
be the only tree seen during a day’s hike. It impotency, sore throats, coughs, convulsions,
would have resulted from a seed dropped by abscesses and ulcers – and even osteomyelitis.

The Villager • Issue 8 2021 • 19