Page 25 - Fourways Gardens August 2021

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

Fourways Gardens • 23 • August 2021