Boomplantweek en die Internasionale Jaar van Woude - Dendro.co.za

EXTRA

Aloe dichitoma » Foto: Jan Lerm
Acacia erioloba (kameeldoring), Thabazimbi » Foto: Gideon Steyn
Boomplantweek en die Internasionale
Jaar van Woude 2011
Die meeste natuurlike inheemse bosse en woude
in Suid-Afrika kom hoofsaaklik in die ooste van
die land, al langs die kuslyn voor. Alhoewel hierdie
inheemse woude die kleinste biome is, word die
grootste biodiversiteit hier aangetref. Verder noord
en in die binneland kan klein lappies woude aan
die suid-oostelike hange van die Soutpansberg en
Drakensberg in Limpopo en Mpumalanga, asook in
die binneland van die Oos-Kaap en Kwa-Zulu Natal,
aangetref word. Die meeste van hierdie woude is
nie groter as 100km2 nie. Die uitsondering is die
die Knysa- en Tsitsikama-woude, wat relatief groot
oppervlaktes beslaan. Die totale oppervlakte van
inheemse woude in Suid-Afrika beslaan ‘n skamele
0.5miljoen hektaar van die totale oppervlakte
van Suid-Afrika. Daarteenoor bedek uitheemse
aangeplante plantasies, wat hoofsaaklik uit
Eucalyptus en Acacia spp. afkomstig uit Australlië
en Pinus radiata uit Noord-Amerika bestaan, 1.7
miljoen hektaar of 1.2% van die totale landmassa in
Suid-Afrika.
Eens op ‘n tyd het natuurlike woude die grootste
gedeelte van die aarde se oppervlakte bedek.
Vandag word hierdie woude teen ‘n tempo van 35
km2 per dag vernietig. Die ketting reaksie wat dit
veroorsaak het ‘n vernietigende uitwerking op die
biodiversiteit, verhoogde grond erosie en verlies
aan water. Voor die aankoms van Europeërs in
Suid-Afrika gedurende die 17de eeu, het groot
troppe olifante en buffels in die Suid-Kaapse
woude voorgekom. Die diere moes swig voor die
geweervuur van die kolonialiste, en in 1883 is die
laaste buffel in die Knysna-woud geskiet. In 1920
was daar ongeveer 12 olifante in die woud oor, en
volgens ‘n opname in 1994, was daar slegs een
olifant oor. Vandag is dit onseker of daar nog enige
olifante in die woud voorkom. Die Dukukdukuwoud
in die noorde van Kwa-Zulu Natal, wat eens
een van die grootste inheemse woude in Suid-Afrika
was, beslaan vandag ‘n oppervlakte van net 3500
hektaar. Gedurende die tydperk tussen 1800 en
2000 het die inheemse woud oppervlakte in Suid-
Afrika met ongeveer 40% verminder. Die grootste
volume van woud produkte word deur plattelandse
Naas Grové
voorwoord
preface
gemeenskappe benut, waarvan brandhout
ongeveer 51% verteenwoordig. Die gebruik van
plantprodukte in tradisionele medisinale praktyke,
afkomstig van spesies soos Cassiporea malosana,
Erythropleum lasianthum, Occotea bulatta, Catha
edulis en Warburgia salutaris, het tot gevolg dat die
meeste van die hierdie spesies op die rand van
uitwissing is.
Dit is onder andere teen dié agtergrond dat die
Verenigde Nasies besluit het om 2011 as die
Internasionale Jaar van Woude, met die hooftema
Mense en Woude te verklaar. Die doel hiermee is
om die mensdom bewus te maak dat volhoubare
woud bestuur, bewaring en volhoubare
ontwikkeling van alle tipes woude tot voordeel
van die huidige en toekomstige geslagte is. Ons
het immers nie die aarde by ons ouers geërf nie,
maar leen dit by ons kinders.
Ek het myself al baie die vraag gevra of een mens, of
een gemeenskap of ‘n paar vrywillige organisasies
‘n verskil kan maak in die lewe van kinders, die
planeet en ons omgewing? Dit is mense soos
Wangari Maathai, die Keniaaanse kampvegter vir
die bewaring van Kenia se inheemse woude, wat ‘n
mens weer hoop gee. Sedert 1977 was sy betrokke
by die ‘Green Belt Movement’ in Kenia en dit het in
2004 aan haar die Nobel prys vir Vrede besorg.
Haar leuse inspireer vandag nog duisende gewone
mense: ‘…when we plant trees, we plant the seeds of
peace and seeds of hope’.
Behalwe vir die verskillende boomplant aksies
waarby die Dendrologiese Vereniging vanjaar
betrokke was, is daar ook in samewerking met
die SABC se Radio Sonder Grense (RSG) ‘n projek
geloods om inheemse groot bome op te meet. (kyk
berigte elders). Dit is ‘n projek waarby die hele
familie betrokke kon raak, die natuurwetenskappe
onderwyser, sy leerlinge asook die boer op
die plaas. Wanneer ons dus hierdie jaar ‘n
boom plant, doen ons dit met ‘n gesindheid van
verantwoordelikheid en die wete dat ons saam ‘n
verskil kan maak.

Cussonia paniculata var. sinuata » Foto: Marnhe du Plooy
I never saw a discontented tree. They grip the ground as though they
liked it, and though fast rooted they travel about as far as we do. They go
wandering forth in all directions with every wind, going and coming like
ourselves, traveling with us around the sun two million miles a day, and
through space heaven knows how fast and far!
26
32
34
65
Dialogue / Dialoog
07 Die Gansbaai-boom
Tree Stories / Boomstories
09 Die Thabazimbi-bosveld se groot kremetart
12 Kommentaar oor die groot kremetart van Gannahoek
15 The twins that became triplets
16 Tree Survey in Sekhukhuneland
Review / Review
STAY IN TOUCH / BLY IN KONTAK
Web: www.dendro.co.za
Email: dendrosoc@esnet.co.za
Fax: 086 670 7715
Postal: Postnet 2054, Private Bag 82234, Rustenburg, 0300
Besoek ons ook op Facebook vir meer interaksie.
Find us on Facebook for more intercation.
COVER PHOTO / VOORBLAD FOTO
Carpenter Bee on Crotolaria capensis (Cape Rattle-pod)
Foto geneem deur: Lloyd Edwards
inhoud
contents
23 Some comments on Tšate from a member of the Botanical Society
26 Die Maroelabos van Tshipise-”duin”
28 Palmbome: Koninklike plante
32 Mynbou in Limpopo provinsie Die Dendrologiese Vereniging se rol
34 Classification and nomenclature of the genus Acacia
44 Underground trees of the Pondoland Centre
47 Virtual Tree Herbarium (ViTH)
49 The Tsate Heritage Site in Sekhukhuneland
52 Vertroetel jy uitheemse indringerplante in jou tuin?
55 Is bome swak kosmakers?
58 New tree species discovered in KwaZulu-Natal
59 Die invloed van swart turf op boomdiversiteit
Byeenkomste / Events
65 Grootvadersbos excursion
66 Grootboommeet-kompetisie
68 Boomplantfunksie saam met Solidariteit Helpende Hand
68 Dendrological Society Pays for Radar Scan of Tree Giant
68 New Africa Tree Record
5
DENDRON » No/Nr: 43 » November 2011

DENDRON » No/Nr: 43 » November 2011
6
editorial
boomgroete
EDITOR / REDAKSIE:
Naas Grové
LANGUAGE EDITING /
TAAL REDIGERING:
Naas Grové
DESIGN / ONTWERP:
Marnhe du Plooy,
Room for Design
COVER PHOTO:
Lloyd Edwards
PUBLISHER/UITGEWER:
Dendrological Society of
South Africa
Dendrologiese Vereniging
van Suid-Afrika
PRINTING:
4 Images
ADVERTISING /
ADVERTENSIE:
dendrosoc@esnet.co.za
MEMBERSHIP /
LIDMAATSKAP:
dendrosoc@esnet.co.za
ADDRESS / ADRES:
Honorary secretary/
Ere-sekretaris
Postnet 2054,
Private Bag/ Privaatsak
82234
Rustenburg, 0300
PHONE / FOON:
+(27) 82 575 4244
FAX / FAKS:
+(27) 86 670 7715
EMAIL / E-POS:
dendrosoc@esnet.co.za
WEB:
www.dendro.co.za
ISSN : 1991-1539
What do members get for their annual
subscribtion fee?
Very often we are confronted by members who challenge the Central Committee
with questions such as ‘what benefits are there in joining the Society and what do we
get for our subscription?’
Although this is not an attempt to justify the work of the members of the Central
Committee, it is maybe worth the effort to contemplate on what has been happening
‘behind the scenes the past year’.
editorial
boomgroete
• Annual newsletters are designed and published at a cost of approximately R 6 500 per newsletter
• Publishing of the glossy Dendron magazine at the end of the year at a cost of between R 24 000 and R 38 000
• The time that goes into the content management, image sourcing, layout and proofreading, roughly amounts
to 120 hours – that excludes the time and efforts of the contributors.
The total annual revenue of the society through subscription fees amounts to ± R 65 000. The current debtors
are at < R 15 000. From the Central Committee’s management position we secured substantial donations and/or
sponsorships for the following projects, which in all fairness should in a perfect world be financed by means of
normal revenue streams:
• Upgrading and maintenance of the website (coding, SEO optimisation, maintenance, annual registration)
• Because most of the members of the Central Committee are still economically active, Machelle Kukard does
all the administration at a nominal fee of R 500 / month, donated by one of the members of the Central
Committee. Machelle can be directly contacted for membership and subscription enquiries via e-mail at:
info@electrodiesel.co.za
• Printing of promotional material which is being issued to schools and other interested parties at special
occasions such as arbor week to create awareness and grow our society
• Upgrading of our accounting and membership administration systems
• Inputs to the National Register of Big Trees in South Africa where we travel vast distances to measure
nominated trees, all at own cost
• Development of tree identification training courses (both theoretical and practical). Currently we offer four
courses per year with a total revenue of R 20 000
• In conjunction with SABC Radio Sonder Grense we launched, as part of Arbor Week 2011 and the International
Year of Forests, various radio talk shows between 1 and 8 September as well as a ‘big tree measurement’
competition. All the prizes for the latter have been sponsored by individuals.
• Together with SANBI we printed A0 Tree of the Year posters which is distributed to our sponsors, schools,
nurseries, etc.
• The Society donated R 10 000 from sponsorships received to the Dictionary of South African Trees by Van
Wyk, Van den Berg, Coates-Palgrave & Jordaan
• None of the above would have been possible had we only relied on membership fees.
Over and above what I have already mentioned, members of the Central Committee pay visits to various branches
throughout South Africa at their own cost. We also travel long distances to deliver tree talks at various occasions
such as agricultural shows, conferences, schools, etc.
With regards to activities at branch level we leave it pretty much to the local structures to keep our members
satisfied, stimulated and involved. It is the local management committee’s prerogative to interpret the society’s
mission in a way they deem fit, as long as it doesn’t damage or compromise the society’s image in any way.
However, it is always problematic where these structures do not exist.
At the initiative of the Central Committee we have arranged joined outings in which various branches participated
and went as far as Pafuri in the Limpopo Province, Leshiba Wilderness, Nwanedi and Gundani in the Soutpansberg,
St Lucia Lake in Kwa-Zulu Natal and Modikwa in the North West Province to name a few. As a valued member
of the Society I urge every member to join in at any activity arranged by any branch, anywhere and to share
your wonderful experiences with us. These will appreciatively be carried in either one of the newsletters or the
Dendron.
On behalf of the Central Committee I wish you all the timeless treasures of Dendrology, the worth of home and the
love of your family and above all the good company of caring, true friends during the festive season.
Naas Grové
President
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DENDRON » No/Nr: 43 » November 2011

DENDRON » No/Nr: 43 » November 2011
8
dialogue
dialoog
Laat my net toe om julle van ons “ Boom “ op Gansbaai te vertel. Ons
boom is `n Melkhoutboom (Sideroxylon inerme) geleë te Kerkstraat 27,
Gansbaai en dit beslaan ongeveer een derde van ons erf. ( 225m 2 )
DIE BOOM GANSBAAI
My Pa het die erf in 1988 gekoop na aanleiding van die volgende
gebeurtenis: Die vorige aand /nag het my Pa van ‘n groot boom
gedroom en nadat hy die volgende dag saam met my ma ‘n ent gaan
stap het, het hulle die boom gewaar. Net daar en dan is daar toe
besluit om hierdie huis aan te koop. Die huisie was maar egter bitter
klein, slegs 100m 2 , maar dit was die boom wat hom aangetrek het.
Na die aankoop van die huis / boom het ons egter nog net pret onder
die boom gehad. Daar is sedert 1988 elke jaar ‘n Kerspartytjie onder die boom gehou asook ons
Nuwejaarspartytjies. Hierdie boom is so groot dat dit maklik 60 mense kan huisves.
Ek ontmoet my vrou dan 10 jaar later onder dieselfde boom en nadat ongeveer nog 6 jaar verloop, trou ons. Die
boom is jaarliks die bymekaarkomplek van vriende en familie. Jaarliks word daar ter ere van die boom ‘n CD
vrygestel en sal dit die dertiende keer wees wat dit gebeur.
Die boom is nie net vir ons spesiaal nie maar stories in Gansbaai doen die rondte dat die Vissermanne ook in die
verlede hulle jaareindfunksies daar gehou het. Daar word ook vertel van menigte ander funksies wat onder hierdie
boom gehou is.
Die boom is vir ons ‘n gerieflike en gemaklike kuierplek en dit huisves onsettend baie verskillende voëlspesies en
party dae is dit sommer net lekker om onder die boom te sit en luister hoe die voëls in die takke baljaar.
Die Gansbaai-boom is nie net onder die plaaslike gemeenskap bekend nie. Talle besoekers van Nederland,
Frankryk en Kanada het al besoek by die boom afgelê en deel ons sentiment oor die plesier wat dit aan ons
verskaf.
Ek hoop en vertrou dat hierdie skrywe julle sal kan laat verstaan die groot waardering wat ons vir hierdie boom
het en dat ons graag sal wil hê dat dit as ‘n spesiale boom registreer word nie net vanweë sy grootte nie maar ook
omdat dit vir ons so spesiaal is.
Vriendelike Boomgroete
Pieter Swart
Redaksionele Kommentaar:
Die Gansbaai-boom
Pieter Swart - Gansbaai
Pieter Swart het die boom onder ons aandag gebring na aanleiding van die Boompraatjies wat op RSG uitgesaai
was. Die boom sal binnekort besoek word om opgemeet te word.
dialogue
dialoog
9
DENDRON » No/Nr: 43 » November 2011

THABAZIMBI SE GROOT KREMETART » Foto: Naas Grové
tree stories
boomstories
Die Thabazimbi-bosveld se groot kremetart
Die mense van Leeupoort-vakansiedorp is lief vir
die natuur. Die Koedoeskop omgewing bied
oneindig veel, onder andere ’n ryk verskeidenheid van
inheemse bosveld bome. ‘n Groep natuurliefhebbers
wat ’n besondere belangstelling in die omgewing se
bome het, is die lede van die Kierieklappertak van
die Dendrologiese Vereniging van Suid-Afrika.Hierdie
groep glo dat liefde vir die natuur word geskep
deur kennis van die natuur. Daarom poog hulle om
elke tweede Woensdag van die maand iewers in die
omgewing te gaan stap, met die hoofdoel om meer
te leer van bome. Dit is vebasend hoeveel meer
nuwe bome bygeleer word, maar ook hoeveel nuwe
inligting oor reeds bekende bome bekom word.
Hierdie groep het in Augustus 2010 besluit om besoek
af te lê by die groot kremetart by Gannahoek. Die
Augustus oggend lug was geniepsig koud toe sewe
voertuie en 22 opgewonde siele by Leeupoort se
hek uitry. Die roete na Gannahoek neem hulle deur
Vliegepoort verby Dwaalboom en anderkant die
Rooibokkraal grondpad is die ingang na Gannahoek
Game Lodge. Die eienaar Jean Taljaard onvang die
gaste hartlik en na so drie kilometer deur Acacia-veld,
asof uit die niet veskyn die kolos van ’n bosveld reus
voor hulle op.
Die stilte is tasbaar en met die naderstap kan die
verstomming op almal se gesigte duidelik gesien
word. Dit neem ’n aansienlike tyd om almal aan Jean
voor te stel. Daar word onder mekaar vertel dat
geleerdes meen die boom kan ‘n 1 000 jaar oud wees!
Die kremetart (Adansonia digitata) is die aarde se
grootse ‘vetplant’. Die genusnaam Adansonia is
ter ere van die Franse snydokter Michel Adanson
(1727 – 1806) en digitata verwys na die handvormige
saamgestelde blaar wat normaalweg uit vyf blaartjies
bestaan. Die kremetart word in Afrika, meestal suid van
die Sahara aangetref. In Suid-Afrika is die natuurlike
verspreiding beperk tot Mpumalanga en die Limpopo
provinsies. Wat die spesifieke plant so uniek maak is
dat dit waarskynlik die grootste natuurlike kremetart
is wat die verste suid en wes in Suid-Afrika voorkom.
Soos wat dit maar gaan met die geskiedenis is daar
ook vele staaltjies, legendes en mites gekoppel aan
die bestaan van die boom. Omdat die boom so
geisoleerd en amper buite sy natuurlike verspreidings
gebied voorkom, bestaan die legende dat die
oorspronklike saad afkomstig is uit Kenia. Dit sou hier
beland het as gevolg van mense wat vir die koningin
van Skeba goud uit die Pilanesberg kom haal het!
Hierdie legende word versterk deur die storie dat
Doep Du Plessis - Kierieklappertak
dieselfde koninging haar tin vanaf Leeupoort gekry
het. Die mees logiese rede vir die verspreiding van
die saad is dat dit deur diere, soos olifante, geskied
het.
’n Ander legende wil hê dat die Boesmans
verantwoordelik was vir die gat in die stam en dat
hulle daarin sou skuil. Van die name wat op die stam
uitgekerf is lyk nogal soos Boesman tekeninge.
Tydens Paul Kruger se leeftyd – so word vertel, was
hierdie deel van die bosveld net in die winter besoek
om te jag. Noord van Vliegepoort was tsetsevlieg
gebied wat die wêreld ongeskik gemaak het vir
boerdery. Dit is bekend dat die ou President gereeld
in die winter op die plaas Gannahoek gejag het en
onder die kremetart kamp opgeslaan het. Dit is ook
tydens een van die jagtogte dat sy hand vermink was
in ’n ongeluk met ’n pangeweer.
Aan die begin van die vorige eeu is daar begin om
plase in die omgewing uit te meet. Omdat hierdie
boom so ’n besondere baken was het landmeters
dit gereeld as verwysingspunt gebruik. Vuurpyle is
vanuit die kruin van die boom geskiet om hul posisies
in plat bosveld te kon bepaal.
Dit wil lyk asof die plaas Gannahoek aan Paul Kruger
toegeken was, of aan een van sy dogters of aan ’n ene
Eloff wat met een van sy dogters getroud was. ’n Dr. de
Ridder is weer met een van Eloff se dogters getroud
en klein Rob van Rensburg trou toe met ’n dogter van
De Ridder. Gedurende dié jare was die kremetart
boom ’n gewilde bymekaar komplek. Dit is dan ook
nie vreemd nie dat posstukke afkomstig uit Botswana
hier gelaat is om afgehaal te word uit Pretoria. Baie van
die groep wat die boom dié dag besoek het, het in die
omgewing groot geword. So word vertel dat Geloftefeeste
hier gehou was. Politieke partye het hul stryd
in die skadu van die boom gevoer. ’n Ander ou vertel
van jukskei wat hier gespeel was en hoe jong kinders
wegkruipertjie in die boom gespeel het. As die boom
kon praat, wat sou hy ons vertel het?
Almal het met groot ontsag om die boom beweeg,
dit aangeraak, en die name wat op die stam uitgekerf
is probeer ontrafel. Die baie kartels en plooie in die
stam herinner ’n mens aldeur aan ouderdom. By die
bek van die gat in die stam soek ek na ’n patroon
doppie wat ek 40 jaar gelede daar gesien het. Dit is
nog steeds daar asof dit gister daar ingeslaan was.
Dit is ’n indrukwekkende boom en van die waarnemings
wat gemaak is, is die volgende:
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DENDRON » No/Nr: 43 » November 2011

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12
tree stories
boomstories
DIE THABAZIMBI-BOSVELD SE GROOT KREMETART
• Daar is baie bogrondse wortels, sommige 20m
lank. Het dit iets te make met die grond tipe?
• Dit het nege mans wat hande vat geneem om die
boom te omsingel.
• Die teenwoordigheid van vlermuise is duidelik
aan die hoeveelheid vlermuis mis wat in die gat
in die stam voorkom. Vlermuise is onder andere
verantwoordelik vir die bestuiwing van die
blomme van die plant.
• Daar is opvallend baie name op die stam
uitgekerf. Sommige datums dateer 100 terug.
Paul Kruger se voorletters is uitkenbaar saam
met talle ander, wat ’n aanduiding is dat die
boom deur baie mense besoek was. Saam met
die groei van die boom het die name ook al hoër
teen die stam opgeskuif.
• Veertig jaar gelede was die bek van die gat in
die stam so groot dat ’n volwasse man daar kon
inklim. Dit is nou so klein dat slegs ’n jong kind dit
sal regkry.
• Bo in die takke is daar oorblyfsels van voël neste.
Jean vertel dat bruinslangarende gereeld in
die boom kom broei. Dit verklaar dan ook die
slangvel reste wat hoog in die takke hang.
• Oorblyfsels van blomme een vrugte is onder die
boom gevind wat bevestiging is dat die vlermuise
hul werk doen.
INSKRIPSIES OP DIE STAM » Foto: Naas Grové
Dit is voorwaar ’n indrukwekkende boom en het dit die groep
twee ure geneem om fotos te neem, die teenwoordigheid van
die kolos in te adem en om afskeid te neem.
OU BEN VAN GANNAHOEK, wat sy eie storie het om te vertel » Foto: Naas Grové
J.A. Schoonees vra in sy brief van 23 Desember of sy
kremetart in Pretoria die verste suid in Afrika is.
By wyle genl. Van der Spuy se plaasopstal, ‘n paar
kilometer suid van die Wit Umfolozi-rivier langs die pad
tussen Ulundi en Melmoth, is ‘n kremetart aangeplant. In
die sewentigerjare, toe ek by Ulundi werksaam was, was
die kremetart al ‘n skotige 4 m hoog.
Die suidelikste natuurlike kremetartboom waarvan ek weet,
is die een op die plaas Gannahoek tussen Thabazimbi en
Makoppa in die Thabazimbi-distrik.
Dat hier ‘n natuurlike een gegroei het, is self snaaks, want
daar is nie ander naby nie en hulle is nie alleenloper-bome
nie. Hoe die moederpit daar gekom het, kan mens maar
raai. ‘n Olifant wat baie ver langs die Limpopo op geloop
het, is die enigste moontlike draer waaraan ek kan dink.
Pres. Paul Kruger het glo ‘n winter of twee by die kremetart
sy jagkamp opgeslaan.
Bron:
http://152.111.1.88/argief/berigte/beeld/2002/12/24/8/3.html
DIE THABAZIMBI-BOSVELD SE GROOT KREMETART
Briewe uit die argiewe
Dié kremetart is die verste suid
Paul Fouche - Modimolle (Nylstroom)
tree stories
boomstories
?
13
DENDRON » No/Nr: 43 » November 2011

DENDRON » No/Nr: 43 » November 2011
14
tree stories
boomstories
KOMMENTAAR OOR DIE GROOT KREMETART VAN GANNAHOEK
Kommentaar oor die groot kremetart van Gannahoek
Die groot kremetart van Gannahoek naby Makoppa in
die Thabazimbi-distrik trek reeds vir jare die aandag,
nie alleen weens sy ooglopend hoë ouderdom nie,
maar veral omdat dit die enigste van sy soort in
daardie omgewing is en weens die talle legendes
en staaltjies daarom heen. Daar is ook al beweer dat
dit die kremetart met die mees suidelike natuurlike
verspreiding in Afrika is.
Is die Gannahoek-verspreiding by 24˚ 26’ 16.7’’
Suid buitengewoon vir ‘n kremetart?
Gannahoek se kremetart is naby die suidelikste grens
van die spesie se verspreiding in Afrika. Maar dit is nie
die mees suidelike natuurlike boom van dié spesie
op die kontinent nie. Dié status behoort waarskynlik
aan ‘n kremetart in die Nasionale Krugerwildtuin of
Mosambiek. Daar staan byvoorbeeld in die wildtuin
‘n boom wat vir toeriste toeganklik is by 24˚ 37’ 6.29”
Suid. Alhoewel dit met die eerste oogopslag lyk of die
Gannahoekboom wat verspreiding betref ‘n uitskieter is
wat buite die spesie se natuurlike verspreidingsgebied
groei, is dit nie die geval nie. Net wes van Gannahoek
en op byna dieselfde breedtegraad in Botswana groei
daar kremetarte by Mochudi. Laasgenoemde is na
bewering die suidelikste natuurlike verspreiding in
Botswana. Elders in die Waterberg is daar enkele
kremetarte noordoos van Gannahoek in onder
andere die Lapalala-wildernisgebied. Die naaste
hoofverspreidingsgebied van die kremetart is egter
verder noord in die Limpopovallei, veral agter die
Soutpansberg. In die meegaande bydrae word
genoem dat die Gannahoekkremetart die grootste
natuurlike boom van sy soort is wat die verste wes (by
27˚ 08’ 46.7” Oos) in Suid-Afrika voorkom. Die stelling
blyk korrek te wees.
Hoe word die geïsoleerde voorkoms van die
Gannahoekboom verklaar?
Die boom by Gannahoek is óf die laaste oorblywende
lid van kremetartbevolkings wat vroeër in daardie
gebied gegroei het, óf dit het daar beland nadat ‘n
saad deur langafstandverspreiding ver weg van die
moederboom suksesvol ontkiem en gevestig het.
Dit is bekend dat die verspreiding van plantspesies
oor tyd verander in ooreenstemming met veral
natuurlike klimaatsveranderinge. So byvoorbeeld is
daar al stuifmeel van bosveldbome in afsettinge in
die Waterberg gevind wat tans nie meer natuurlik in
die gebied voorkom nie. Dit is nie onmoontlik dat die
Prof. Braam van Wyk
kremetart by tye in die verlede in groter getalle verder
suid as tans gegroei het nie. In sodanige geval sou die
boom by Gannahoek ‘n reliek uit ‘n vervloë tyd wees.
‘n Meer waarskynlike verklaring is dat
die Gannahoekboom gevestig het na
langafstandsaadverspreiding. Die geskiedenis van
die mens is nou verweef met die verspreiding van
baie plantsoorte in Afrika. Die mens is nie alleen
inheems in Afrika nie, maar dit is bekend dat hy
in historiese tye ‘n aktiewe rol gespeel het in die
verspreiding van baie boomsoorte op die kontinent.
In die opsig is die kremetart ‘n bekende voorbeeld.
Verspreidings waarby die mens betrokke was is
dikwels met argeologiese terreine geassosieer. Dit
sal insiggewend wees om uit te kyk vir moontlike
argeologiese tekens van menslike aktiwiteit in die
omgewing van die Gannahoekboom.
Die legende dat saad van die
Gannahoekboom deur die mens van sover weg as
Kenia na sy huidige groeiplek gebring is, is alhoewel
nie onmoontlik nie, hoogs onwaarskynlik. Daar is
soveel ander kremetartbome nader aan Gannahoek
waarvandaan saad veel makliker kon gekom het. Die
kremetart toon groot genetiese variasie in verskillende
dele van Afrika, tot so ‘n mate dat daar al voorstelle was
om dit in verskillende spesies te onderverdeel. Veral
die vorm van die vrugte toon groot streeksvariasie.
Dit sal sekerlik moontlik wees om met gesofistikeerde
DNS-tegnieke die naaste verwante van die
Gannahoekboom te bepaal, of ten minste ‘n beweerde
Oos-Afrika verbintenis uit te skakel of te bevestig. In
die verband is dit interessant dat die onderbroke
verspreiding van ‘n ander bosveldboom, die veel
skaarser bosveldrooiklapperbos (Erythrophysa
transvaalensis), ook al gekoppel is aan bewegings
van die mens tussen plekke waar in antieke tye onder
andere vir tin gemyn is in Suid-Afrika en Zimbabwe.
Saad van die spesie is vermoedelik deur die mense
as krale gebruik.
Kremetartsaad is bestand teen uitdroging,
bly lank kiemkragtig en kan potensieel oor lang
afstande versprei. Dit het ook ‘n harde saadhuid (is
sogenaamd hardskalig) en ontkiem beter nadat dit
deur die spysverteringskanaal van ‘n dier gegaan het.
Benewens die mens kon verskeie ander diere ‘n rol
by die inbring van die Gannahoekboom se saad van
iewers elders gespeel het. Moontlike saadverspreiders
oor langer afstande sluit in die olifant, swartrenoster en
sekere boksoorte, byvoorbeeld die eland. Bobbejane
versprei die saad in hul mis en speel ‘n belangrike rol
om kremetarte oor veral korter afstande te versprei.
Min is bekend oor die verspreiding van kremetartsaad
deur voëls (byvoorbeeld neushoringvoëls en
bosveldpapegaaie), maar dit is beslis ook ‘n
moontlikheid.
Waarom is daar slegs ‘n enkele kremetartboom
by Gannahoek?
Die feit dat daar in die omgewing van Gannahoek
nie ‘n bevolking van kremetarte is soos wat mens
sou verwag nie, is ongewoon. Dit mag onder andere
daarop dui dat huidige omgewingstoestande nie
meer gunstig is vir die natuurlike vestiging van
kremetartsaailinge in die betrokke omgewing nie. So
iets sou mens verwag indien die boom inderdaad ‘n
reliek is wat uit ‘n tydperk dateer toe die gebied se
klimaat anders was as wat dit tans is.
‘n Sleutelvraag is of die Gannahoekboom vrugte
dra en indien wel, of hulle kiemkragtige saad bevat.
Bestuiwing by die kremetart word bewerkstellig deur
veral vrugtevlermuise, maar ook nagapies en verskeie
soorte insekte. Dit kan aanvaar word dat bestuiwing
van die Gannahoekboom se blomme nie ‘n probleem
behoort te wees nie.
Ondanks die feit dat die kremetart een van die mees
bestudeerde bome in Afrika is, is daar nog onsekerhede
oor aspekte van sy voortplantingsbiologie. Daar word
Studies het aangetoon dat die gemiddelde
toename in groei in omtrek van ‘n kremetartboom
in die Zambesi vallei kan wissel van 0.15cm - ±
0.75cm / jaar was teenoor die 0.01cm / jaar in die
Limpopovallei. (Guy, G. L. 1970. Adansonia digitata
and its rate of growth in relation to rainfall in South
Central Africa. Proceedings Transactions Rhodesia
Scientific Association 54 (2) 69-84).
Sodra kremetartbome ouer word verminder die
groeitempo en kan hulle ‘krimp’ as gevolg van
hidroskopiese kondisies. Veranderinge is ook meer
drasties as die boom vol blare is en vanselfsprekend
speel die 40% water inhoud in die stam ook ‘n rol in
die bepaling van die werklike stam omtrek van die
boom. (Fenner, M. 1980. Some measurements on
the water relations of baobab trees. Biotropica 12(3):
205-209). So byvoorbeeld is ‘n kremetart boom wat in
1946 opgemeet is 60 cm dunner gewees as wat dit in
1931 was! (Esterhuyse et al. 2001)
KOMMENTAAR OOR DIE GROOT KREMETART VAN GANNAHOEK
Redaksionele Kommentaar
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boomstories
byvoorbeeld steeds gespekuleer of ‘n kremetart
na bestuiwing met sy eie stuifmeel vrugbare saad
kan vorm al dan nie, met ander woorde is die boom
selfverenigbaar of selfonverenigbaar. Die aanduidings
is dat stuifmeel van ‘n ander boom nodig is om vrugbare
saad te vorm, met ander woorde die kremetart is
selfonverenigbaar en benodig kruisbestuiwing.
Maar dit is nie so eenvoudig nie. Dit wil voorkom
asof kremetarte wat buite hul natuurlike
verspreidingsgebied aangeplant is na selfbestuiwing
wel vrugte met saad vorm, maar dat die embrio op
‘n vroeë stadium aborteer en dat die saad gevolglik
nie kiemkragtig is nie, ‘n verskynsel bekend as laatselfonverenigbaarheid.
Indien kruisbestuiwing tussen
verskillende bome nodig is, dan kan die gebrek aan
ander kremetartbome in sy omgewing ‘n verklaring
bied vir die enkele boom by Gannahoek.
Volgens die meegaande bydrae blyk dit dat die
Gannahoekboom wel vrugte dra. Dit sal insiggewend
wees om vas te stel of die saad in die vrugte normaal
ontwikkel het en kiemkragtig is. Waarnemings op
hierdie boom kan dalk help om die onsekerheid of
kruisbestuiwing noodsaaklik is vir die suksesvolle
voortplanting van die kremetart uit die weg te ruim.
Sulke waarnemings sal natuurlik slegs betekenisvol
wees indien daar geen aangeplante kremetarte is wat
in tuine in die omgewing van die Gannahoekboom
blom nie.
Gebaseer op Guy (1970) se aanname dat die
kremetartboom teen ‘n tempo van 0.75cm / jaar in
omtrek groei, kan kremetartbome se ouderdom
rofweg bepaal word deur die volgende formule te
gebruik: (Barnes, R.F.W. 1983. Effects of elephant
browsing on woodlands in a Tanzanian National Park:
Measurements, models and management. Journal of
Applied Ecology 20: 521-540.)
Ouderdom in jare = 0.213 X stam omtrek in cm
Indien hierdie formule op die Gannahoek-boom
toegepas word is die boom ongeveer 255 jaar oud.
Terselfdertyd sou die Sagole-boom naby Tshipise ±
698 jaar oud wees.
Die wêreld se ‘vetsugtigste’ boom is die Taxodium
mucronatum (Mexican Bald Cypress) met ‘n omtrek
van 57.9m, ‘n deursnee van 18.4m, hoogte van 41.85m
en die waarskynlike ouderdom is ± 1 230 jaar. Die
boom groei in ‘n begraafplaas naby die dorpie Maria
del Tule in Oaxaca, Mexiko. (Esterhuyse et al. 2001).
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The partners in the venture » Leon Visser (climber) and Brof Brian Bredenkamp (ground crew) at the base of the tallest tree in Africa.
The twins that became triplets.
The weather in the Boland was near-perfect early
last week, but in the forest areas of Limpopo it was
so bad that two of South Africa’s four Albatross aircraft
flew into the side of a mountain. While rescue parties
were looking for the crash site, two foresters from
Stellenbosch, Brian Bredenkamp and Leon Visser
were in the rain in the plantations of Magoebaskloof,
measuring trees. Brian is Emeritus Professor of Forest
Management at the University of Stellenbosch and
serves on the Minister of Forestry’s advisory panel
for the National Champion Tree Project while Leon
is an arborist and owner of Trees Unlimited. He is
passionate about climbing trees. There is a synergy
with the former’s expertise in forest mensuration and
the hobby of the latter. Leon climbs the tallest trees
in the country and drops a tape to his ground crew,
Brian, who then records the height. As Brian jokingly
puts it; Leon merely holds the end of the tape while he
measures the tree.
Local foresters on Woodbush Forest had discovered
three huge Mexican yellow pines (Pinus oocarpa)
that had been planted in 1905 and left when the rest
of the stand was clearfelled some seventy years ago.
The stand had not been replanted and these three
now tower above the indigenous forest that has reestablished
itself. The trees had been reported to
the Department of Forestry and the responsible
official had asked Stihl (South Africa) to sponsor the
measurement of the trees. Stihl had kindly agreed
to cover the travel expenses of Brian and Leon who
flew to Johannesburg and then travelled by road to
Magoebaskloof, via Polokwane, on Sunday morning.
By nightfall the first of the three trees had already
been climbed and measured and the throw lines were
already in the crown of the second.
On Monday morning Leon was up the 50 m tree in
less than an hour despite the pelting rain and before
lunch the objectives of the trip had been met. The
trees had been measured and had been dubbed the
Matrons of Magoebaskloof. However, this provided an
opportunity!
The Matrons were only a short walk from the Twin
Giants of Magoebaskloof. These were two Sydney
Izak van der Merwe
THE TWINS THAT BECAME TRIPLETS.
blue gums (Eucalyptus saligna) that Leon had climbed
and Brian had measured the year before. They were
78,5 and 79,0 m tall and were not only the tallest trees
on the African continent, they were the tallest planted
Eucalypts in the world. They had been identified for
climbing from satellite imagery and when Leon was
up in the crowns he’d seen another tree, mere metres
away, that he suspected was even taller. However, by
that time it was already dark on the forest floor and
there had not been an opportunity to climb the tree.
Now that opportunity had arrived.
Opportunity might not be the best word, of course. Most
of the day was available but it was raining continuously
and the bark of a gum tree is a lot smoother than that of
a pine tree. It would be dangerous to climb in the rain
because as the roadsigns proclaim; Slippery when
wet! Undeterred, Leon set off. The lowest live branch
was more than 30 m above the ground and it took a
while before it was possible to shoot a lead weight
with an attached throw-line over it. The climbing rope
was pulled over the branch by means of the throw line
and then Leon set off, ankle-locking his way up the
rope. It took another 15 passes to higher branches
and two hours before he reached the top and Brian
attached the end of the tape measure to the climbing
rope. Leon then pulled the end of the tape to the
top of the tree and Brian read the height: 80 m! The
tree is now the tallest known in Africa. There are now
three giant trees in the grove and the Twin Giants of
Magoebaskloof now became the Triplet Giants of
Magoebaskloof.
It may be useful to think about what a height of 80
m implies. Were the tree to stand on the quarter
line of the All Blacks and fall toward the Springbok
line it would flatten the posts! The tallest tree in
Stellenbosch, possibly in the Boland, in Helsehoogte, a
sugar gum next to the old Helshoogte Pass, and that is
a mere 54 m tall. Arguably the most prominent tree in
Stellenbosch is the almost 200-year old Norfolk Island
Pine in front of the Theological Seminary, a tree that is
taller than the steeple of the Moederkerk. The new
Triplet is almost twice as tall!
tree stories
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TREE SURVEY IN SEKHUKHUNELAND
Tree Survey in Sekhukhuneland
Over the week-end of 4 to 6 February 2011 a
group of members from several branches of the
Dendrological Society were privileged to join experts
and delegates from various other Societies to conduct
a survey of the trees and vegetation in the area of
the Tšate Provincial Heritage site in the Sekhukhune
Centre of Plant Endemism. We visited here at the
invitation of Lizanne Nel, who is facilitating a project for
the Sekhukhune District Municipality, but more about
that a little later.
On preparing for the survey, I realised that I knew but
little about this area and started wondering as to what
its possible claim to fame could be. It turns out that the
area is very interesting and in many respects unique.
Where is Sekhukhuneland?
Sekhukhuneland is located within the area bordered
by the Olifants River in the west, the Strydpoort
Mountains in the north, and the Steelpoort River
in the east. It is the land occupied by the Pedi
people, the Bapedi, who belong to the Northern
Sotho linguistic group. In the past, the Pedi had a
much larger territory, occupying the area between
Rustenburg in the west, the Vaal River to the south,
and the lowveld in the east.
Hartwig von Dürckheim
Some Historical Background.
The evening of our arrival, and around a lively
campfire, Lizanne briefly sketched the interesting
history of the area and its people.
The earliest settlers in the region appear to have been
farming communities who established themselves
south of the Limpopo river around 200 AD. These
mark the beginning of the South African Iron Age
period. Some rich archaeological finds of Iron Age
sites in the area of the Tšate Valley are testimony to the
activities of these early people who, it is presumed,
may have been related to the Middle Iron Age culture
of Mapungubwe. These early people were displaced
by the migration of people from Central Africa.
The Sotho people appear to have migrated
southward in successive waves from the Great Lakes
region in Central Africa as from about 1500 AD, and
one of these groups settled in the Western Transvaal
around 1650. Parts of this tribe later moved to
the vicinity of what is today Pretoria. Strife and
competition led to a section of that group to move
east and settle in the Steelpoort area, where the Pedi
nation was then established. By 1800 Thulare was
the leader of the Pedi Empire in the north-eastern
Transvaal. The Pedi then consisted of several tribes,
who enjoyed great wealth under Thulare’s rule and
he is still honoured as a great chief and leader to
this day. Then followed the chaos of the Difaqane
wars (about 1815 to 1836) where the Zulus under
their king Skaka, and later Mzilikazi, laid to waste
and dispersed the tribes that had settled in the
Transvaal. Thulare’s son Sekwati was then the leader,
and he fled with the Pedi to the north where he took
refuge. Some years later he returned and settled in
the area known as Magali’s Location. Sekwati’s son
and successor, Sekhukhune, initially consolidated
the power of the Pedi, but years of drought and a
series of attacks from the South African Republic and
the Swazi chiefdom weakened the Pedi during the
1870s. Around 1845 the Voortrekkers under Hendrik
Pogieter settled at Ohrigstad and concluded
a treaty with the Pedi. In spite of the treaty, cattle
thefts and labour disputes occurred and this caused
friction between the Voortrekkers and the Pedi. This
situation deteriorated for many years until in 1876
the Voortrekkers waged war on the Pedi under
Sekhukhune, but were defeated and had to retire.
TREE SURVEY IN SEKHUKHUNELAND
Confrontation continued until the British annexed
the Transvaal in April 1877.
tree stories
boomstories
In 1878 the Bapedi were at war once more, this
time with the British under Theophilus Shepstone
who viewed Sekhukhune as a hindrance to British
ambitions in the Transvaal. Several inconclusive
battles were fought until November 1879 when, in
an expedition led by Col Baker Russel, 3 500 British
regular troops and 3 000 Transvaal levies combined
forces with 8 000 Swazi warriors to defeat the Pedi. In
a battle lasting five hours the Pedi were vanquished
and Sekhukhune was subsequently captured. He
was sentenced to a long term of imprisonment, but
was released when the British withdrew from the
Transvaal after the first Anglo-Boer War. He was
murdered in 1882 by his half-brother, Mampuru
(who was later executed). Today, built on a boulder
at the foot of the hill where the 1879 action took
place and overlooking the expanse of the Tšate
valley, there is a monument of Sekhukhune as he
contemplates the role he has played in the history
of the Pedi.
After the defeat of the Pedi their homeland was
substantially reduced. Reserves—roughly coinciding
with the core area of the Pedi heartland—were created
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TREE SURVEY IN SEKHUKHUNELAND
for them by the Transvaal Republic’s Native Location
Commission. Over the next hundred years or so, these
reserves were then variously combined and separated
by a succession of government planners. In 1972 the
Northern Sotho homeland of Lebowa was proclaimed
a ‘self-governing’ territory with a population of almost
2 million.
One of the significant European figures in the history
of the Bapedi is Alexander Merensky, missionary,
scientist and surgeon. He was attached to the Berlin
Missionary Society and conducted missionary
work among the Bapedi in the Tšate valley from
about 1861 when Chief Sekhukhune invited him to
build a mission station at Thaba Mosega. By 1865,
however, relationships between Sekhukhune and
the Christians deteriorated and Merensky and his
converts had to flee the area. They settled near
Middelburg where Botshabelo (city of refuge)
was established. Some other notable missionary
figures who worked in the area include Hermann
Wangemann, and Johannes Winter.
Geology, Minerals, Mining and Merensky.
The area around the Tšate Heritage site (and indeed
the greater part of Sekhukhuneland) is geologically
a part of the Bushveld Complex, termed one of
the geological wonders of the world. The Bushveld
complex extends from about Rustenburg in the
west, eastwards towards Lydenburg, and northwards
towards the Soutpansberg. It was formed about
2000 million years ago through a process whereby
huge masses of molten rock rising from below were
squeezed in between layers of sedimentary rock to
form a huge subterranean chamber of rock. These
magmas solidified into different layers or reefs of
material. Later a different type of magma was intruded
above those formations and crystallised as granite.
The formations that we see at Tšate are the rocks of
the so-called “Rustenburg Layered Suite”, the same
formation as found between Rustenburg and Brits.
The Bushveld complex contains large quantities of
relatively rare and economically valuable minerals,
such as chromitite, magnetite, and the platinumgroup
minerals. One of the layers of the Bushveld
complex is called the Merensky Reef after Hans
Merensky, notable geologist and son of Alexander
Merensky, who discovered the reef that carries his
name in 1924 near Steelpoort.
The mineral wealth of the area may also prove to
be a liability and hasten the debasement of the
ecosystem. There is extensive mining in the area,
with all the concomitant side-effects such as mining
dumps, air and water pollution, dust, and scarring
of the landscape. Plans are afoot to further extend
the scope of mining in order to satisfy the voracious
appetite of industry for minerals and the insatiable
greed of a clan of wealthy individuals. Furthermore
and in order to supply water for mining, industries
and to rural communities, the construction of the
De Hoop dam on the Steelpoort River has been
approved by Cabinet. The length of the dam wall
will be about one kilometre, whilst two new bridges
are to be built to reroute sections of the main road
that will be submerged by the rising waters.
Sekhukhuneland Centre of Plant Endemism
(SCPE) The Tšate Heritage Site where we visited
over the weekend of 4 to 6 February 2011 lies more
or less in the heart of the Sekhukhuneland Centre
of Plant Endemism (SCPE), so called because of the
high concentration of plant species within a relatively
small geographic area, in this case Sekhukhuneland.
It is estimated that within the mere 4000 km² area
of the SCPE there are more than 2000 species of
plants, which include about 58 endemics, another 70
near-endemics, and no less than 46 threatened plant
species. The topography of the SCPE consists of rocky
hills, the rugged Leolo Mountains and deep kloofs.
The surface area is covered by basaltic (ultramafic)
rock with high magnesium and iron content, such as is
the composition of the earth mantle.
Near the Tšate Heritage Site lies the expanse of
the Tšate valley with an unrestricted view towards
the north and the silhouette of the Wolkberg in the
distance. The vegetation around the Tšate area is
typically Mountain Bushveld dominated by Kirkia
wilmsii and Acacia caffra.
Tšate Heritage Site Development Project
The SCPE is subject to various serious threats:
Growing informal settlements and unsustainable landuse
activities (such as uncontrolled wood-harvesting)
have caused land degradation with overgrazing and
soil erosion resulting in under-productive land. In
recent years these impacts have been exacerbated
by increased population growth and growing resource
demands. Mining activities occupy a large area,
mostly in the valleys, whilst several new prospecting
licences have also been granted for the area, including
the Tšate Heritage Site. These impacts are likely to
compound in the future.
Part of the Tšate valley was proclaimed as a
Provincial Heritage Site in 2007, and, but for the
small Potlake Nature Reserve (of about 30 km²),
this is the only other conservation area within the
bounds of the SCPE. In 2008 the Sekhukhune
TREE SURVEY IN SEKHUKHUNELAND
District Municipality launched the Tšate Heritage
Site Development Project which strives to discover
and protect the heritage of the Bapedi and the
exceptional biodiversity of the area, whilst also
developing its potential as a tourist destination. In
pursuance of this, community members are being
trained as tourist guides, and also assist with
archaeological excavations. An information office
has been established at the Heritage Site.
In an effort to benefit from the tourism potential of
the area, primarily by creating jobs for the many
unemployed people, the Sekhukhune District
Municipality has commissioned a project team for the
development of Tšate, whilst Lizanne Nel has been
appointed as a facilitator of this project. Lizanne was
our host for the weekend, ably supported by her
husband Gawie. By profession she is a Conservation
Biologist and Tourism Development Expert, and works
through her company, called 4Life Promotions.
To guide our activities of the weekend, and in order
to channel and control our enthusiasm, we got the
following brief from Lizanne:
“PURPOSE: To get the input of
various experts and specialists on
the biodiversity of the area, as well
as the locality and information on
potential tourism attractions and
potential routes.”
Tree Spotting around Tšate
The scope of the survey is broad and it covers different
fields of study; hence, there were delegates from the
Herpetological Society surveying reptiles, from the
Botanical Society assessing flowering plants, there
were Rolf Becker and his team from the Euphorbia
Society, and then there were the representatives of the
Dendrological Society from the branches Pilanesberg,
Magaliesberg, and Waterberg.
The delegates arrived at Tšate valley on the Friday
afternoon, congregating at the camping site from all
different directions. Naas Grové and I shared a car
and we had decided to drive via Middelburg, thus
we approached from the south, travelling along the
course of the Steelpoort River. It was a pleasant
drive, though marred somewhat by the relentless
traffic of heavy ore carriers on the road. The last
part of the route where you travel along the valley
of the Steelpoort River is really quite scenic, and we
enjoyed the drive. There is already a lot of mining
activity in the valley, and we passed a smelter puffing
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TREE SURVEY IN SEKHUKHUNELAND
its waste gasses into an otherwise clear blue sky. A
distance short of Mecklenburg (an old missionary
site) we turned off into the Tšate valley, an extensive
flat at the foot of the commanding Leolo Mountains.
A string of villages bound the gravel road on either
side with children and goats equally trying to outrun
the car as we drive along peacefully. Although the
valley has basically been denuded of most trees,
we stopped to photograph some fine specimens of
Bead-bean trees (Maerua angolensis) and Wormbark
false-thorn (Albizia anthelmintica). The Hedge
Euphorbia (Euphorbia tirucalli) is abundant in the
villages and is being extensively planted to form
impenetrable enclosures for the paddocks that host
goats and cattle at night.
We stopped at the Information Centre to learn more
about the history and facets of Tšate, and were greeted
by an assembly of friendly attendants eager to assist
with interesting morsels of information in exchange
for a cold drink. Nearby, there is a warrior-monument
on an elevated rock commemorating that fateful day
in 1879 when the Pedi were defeated at the hands of
British, Boer and Swazi soldiers.
The camping place is on the outskirts, but yet within
the bounds, of the village. It’s laid out on a single
stand and was rather crowded with an exceptionally
large number of visitors and vehicles. We made our
obeisance trying to remember the names of all the new
friends we met. We found a most interesting group of
people assembled there on that Friday afternoon: From
the Dendrological Society there were some real hardwood
heavyweights such as Erwin Grobbelaar, Nico
Hager, Naas Grové, and Hans Vahrmeijer. Obviously,
there were also some medium- and light-woods, but
I shall not mention any names for fear of retribution.
However, the latter two groups did certainly contribute
extensively to an entertaining and cheerful evening
around a blazing campfire, smothered only by the
cacophonous and disharmonic thump… thump….
thump… emerging from the oversized loudspeakers
of the near-by Shebeen, which continued until the
early hours of the next day.
The next day was Saturday, and in order to get the
maximum coverage we decided to split up into
various groups and compare notes later. Our friends
from the Euphorbia Society went their way, whilst the
tree people explored the mountain side to the south.
There is a mountain track here, negotiable with your
favourite 4X4. Gawie Oberholzer with only a diff
lock on his bakkie had to give up about half-way up
the slippery slope, but it was good practice for him
anyway! We slowly meandered up the slope, most of
us walking whilst the drivers brought up the vehicles
during identification-breaks.
The vegetation type we surveyed on this slope and on
the plateau above is classified as Mountain Bushveld
(one of five vegetation types in the SCPE) and we
found an abundance of tree species though the density
of these was low to medium. Lower down the slope the
Mauve Chinese-hats (previously Holmskioldia, now
Karomia speciosa) were abundant and in bloom, which
few of us had seen before in their natural environment.
Patches of the Yellow Bauhinia (Bauhinia tomentosa)
were readily identifiable by their characteristic
leaf structure and yellow petals. In our group Naas
Grové did most of the identification work, Johan
Cronje maintained the check list, Gert Middelberg
operated the GPS (for the coordinates and altitude of
our sightings), whilst I did quality control. The latter
is quite an easy job, if you know how. You don’t have
to know too much about trees: All you have to do is
to carry a tree manual, and whenever Naas says, for
example: “This is a Groenstam bitter-bessie boontjiepeulboom”(i.e
tongue in the cheek for marula), all you
have to ask is: “Why are you saying that?” You’ll be
surprised as to how much you can learn from this!
We encountered a number of firewood-collecting
gangs making their way up the slope and greeting us
politely. From a distance, and higher up the incline,
you could soon hear the axes chopping and logs
being manhandled in their efforts to provide energy
for their evening meals. Unfortunately the mountain
side is already virtually stripped of all combustible
material and it is sorry to observe the last remnants,
which should rather be allowed to decay naturally in
order to support new life and growth, being carried to
the village in the valley below in large bundles.
The Mountain Seringa (Kirkia wilmsii) are very
common trees on this west-facing slope. Some are
just barely shrub-like, whilst others grow into tall
trees. Towards the saddle of the mountain we spot an
endemic, the Sekhukhune Bushman’s Tea (Lydenburgia
cassinoidesi) and the Bushveld Saffron (Elaeodendron
transvaalensis), both of the latter being members of
the family Celastraceae. There is also a Red-stemmed
Corkwood (Commiphora harveyi) growing happily on
a rock outcrop. As we reach the saddle we take a short
break to view the expanse of the Tšate valley below,
stretching out towards the north-west. We botanise
around the saddle and admire some large specimens
of the Bushveld Kubu-berry (Mystroxylon aethiopicum
subsp. schlechteri) which seem to thrive in this location.
Remarkable also is the abundance of the Monkey’s Tail
(Xerophyta retinervis). The habitat here seems ideal
for these plants, as they grow to a height of more than
two meters, and branch into several stout stems.
From here we drive by car up to a flat and fertile
plateau which is close to the summit of the mountain,
and at an elevation of over 1200 m as against the valley
floor where the elevation is around 850 m. There are
some interesting ruins here, now overgrown densely
by an assortment of vegetation. It is said that this was
one of the hideouts of Sekhukhune for those occasions
that he deemed disappearance to be the better part of
valour. On the way towards the plateau we have our
first sightings of the endemic Sekhukhune Euphorbia
(Euphorbia sekukuniensis), which occurs only in a very
small area around Sekhukhuneland. On the plateau
there are some fine specimens of the Hairy Rock Fig
(Ficus glumosa), tall trees with an umbrella-like canopy.
TREE SURVEY IN SEKHUKHUNELAND
SEKHUKHUNI-NABOOM, Euphorbia sekukuniensis » Foto: Naas Grové
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While scouting around for trees in the area we kept
an eye open for any possible sightings of avifauna
that should be quite abundant around here. However
it is deplorable to report that we had very few bird
sightings. On the plateau I did observe a Blackcrowned
Tchagra dashing from bush to bush;
overhead some Abdim’s Storks were circling for a
while, and at the campsite there was Yellow-billed
Kite hunting for prey. Similarly, we had only a single
sighting of a mammal, a Rock Dassie which fled
hurriedly as we approached. It appears that the Pedi
have different words to describe the various targets of
a hunt: Hunting for birds is performed by young boys
and is called “go tibiša” whilst hunting for game is the
privilege of grown men and is termed “go tsoma”. It
is evident that both groups are doing a thorough job.
Later in the afternoon we drove by car along the gravel
road leading south, and up a steep pass leading to
the west. The road is fine, and we travelled slowly,
botanising the roadside as we went. Atop we made a
break to once more enjoy the vista of the Tšate valley
and the hazy silhouette of a range of hills to the north.
On returning to the campsite we crossed the Motse
River via a low-water bridge. The river was flowing
strongly and cascading downwards over the bridge,
thus creating a waterfall. The temptation was too strong
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TREE SURVEY IN SEKHUKHUNELAND
to resist. After the morning’s hike we felt sweaty and
exhausted, and there is a water shortage at the camp,
which rouses guilt when you climb under the shower.
But the water of the Motse River was actually better: It
looked clean, cool, and inviting. So we stripped and
had a thorough shower provided with the compliments
of the Motse River. Whilst chatting and relaxing in the
near-dusk, Johan Cronje suddenly remembered it was
actually sundowner time and produced a bottle of
fine white wine from the fridge in his car. So we did
some bonding: feet in water, glass in hand. Later, he
remembered that there was actually a bottle of red as
well. Needless to say we returned to camp rather late.
The braai in the evening was once again a huge
success: A lively fire, a pot of pap en sous, and the
aroma of meat roasting on the fire, whilst we discussed
the successes and disappointments of the day.
Between the different groups we had a list of no less
than 138 different species of trees identified on that
day, and this is only within one of the five vegetation
types found in the SCPE. This is a highly remarkable
achievement, since a typical weekend outing of our
Society will seldom yield a list of more than 60 or so
species. You may imagine the tree count should we
be able to spend a few days in the area.
Just to remind us that life is not perfect the local
Shebeen started up in the early evening, and we were
once again entertained to the intolerable .thump…
thump….thump…until well past midnight.
Other attractions in the area.
The appeal of the Tšate area is certainly not limited
to its rich and varied flora: There are several other
attractions of historic, cultural, and geological interest
in the close proximity, and these are easily accessibly.
Exploring these sights may occupy the better part of
a day and will enhance the appreciation of the region.
Among these, the following may be listed:
• Visible surface sections of the Merensky reef and
the chrome layers of the bushveld complex;
• The scars of Hans Merenksy’s first mining
operation;
• Hans Merensky’s office, which today serves as a
house of prayer;
• Various archaeological sites where artefacts of
the iron age hunter-gatherers have been exposed;
• Rock paintings by the aboriginal people;
• The norite music stones which, when thumped,
will produce several different harmonious notes
from a single stone.
MUSIC STONE » Foto: Naas Grové
Comments and Conclusion
What is our evaluation? What about he biodiversity of
the area? What about the tourism potential?
Let me emphasize that, with the very limited exposure
we’ve had to the area of Tšate, we can merely voice
some common impressions, which may actually be off
the mark when examined in greater depth.
It is certainly a wise and enlightened decision of
the Sekhukhune District Municipality to seek other
sustainable sources of economic activity for the area.
Currently it appears as though much of the employment
is dependent on Mining, but Mining, by its very nature,
is an unsustainable source and all that will remain after
30 or 40 years are a degraded ecosystem and scars in
the landscape. In the mean time, and spurred by the
transient income from mining, the local population will
have increased substantially, and the pressures on the
environment will have multiplied.
We have found that the area is a tree-lover’s paradise,
but at the same time subject to various serious threats
some of which have been alluded to above.
I believe that, regretfully, the current tourism potential
of the immediate Tšate area to be rather limited due
to considerations such as: Distance from the market
(some 350km from main centres), proximity of
villages and human habitation, the effects of mining,
degradation of the environment, rareness of avifauna
and mammalians, and (currently) inadequate camping
facilities. A real tree-lover will, no doubt, endure and
defy these inconveniences but, again regretfully, there
are so few of us!
On the other hand: The SCPE is, by all reports, a
rich and diverse area that is demanding very special
and considerate preservation against the threats
and pressures facing it. It deserves placing a large
and contiguous tract of this land under legislated
conservation, preferably incorporating the six
vegetation types identified by Dr Siebert. Preservation,
rehabilitation and restocking of such land will in time,
Sources:
Publications and Reports:
1. Various Information Brochures kindly supplied by Lizanne
Nel
2. HOARE, D. 2007. Scoping Report: Ecological Study of the
proposed Steelpoort Integration Project.
3. McCARTHY, T. & RUBIDGE, B. 2005. The Story of Earth &
Life, Struik.
4. NORRIS-NEWMAN, C.L. 1976. With the Boers in the
Transvaal. Africana Reprint Library.
5. SIEBERT, S.J. 2001. Vegetation on the ultramafic soils of
TREE SURVEY IN SEKHUKHUNELAND
Some comments on Tšate
from a member of the Botanical Society
Sylvie Köhne
no doubt, encourage tourism and support sustainable
job creation.
But such ventures are expensive and need to be
financed. The answer, in my mind, is that the Mining
Companies may be approached for funding. After
all, the Mining Companies are reaping where they
did not sow; they are exhausting the valuable assets
of the area and benefiting mostly their investors, the
politicians, and administrators.
It is our sincere hope that the dendrological, floral
and other treasures of the SCPE and the Tšate valley
will be preserved and enhanced, and that we shall
be able to bring many a more interesting visit to this
fascinating area.
The Limpopo Branch of the Botanical Society joined the Dendrological Society at Tsate, and enjoyed
meeting lots of different people. The plant life impressed the entire party and there was something for
everyone: special trees for the dendrologically inclined, beautiful forbs with huge ornamental potential
for the tissue culture expert, some spiny Euphorbias for the succulent enthusiasts, and grasslands
exploding with flowers of every kind after the good rains. As summit grasslands support high plant
diversity and numbers of endemic plants, the BotSoc group focussed on the grasslands around the Tama
Kgoshi peak of the Leolo Mountains on Saturday. Twenty-one herbaceous flowering plant species were
recorded, including the densely flowered orange Gladiolus crassifolius, the perfectly camouflaged green
Habenaria orchid species as well as the beautiful red Streptocarpus dunnii. Apart from their conservation
value, many of the grassland plants have medicinal, cultural and nutritional value for the local rural
communities. A herdsman offering Zantedeschia tubers for sale was encountered, and erosion caused
by overgrazing was noticed. Irreversible transformation of grasslands needs to be controlled as the
most critical ecosystem function that pristine grasslands fulfil is that of water catchment. In a waterstressed
country such as South Africa, their role as collectors of rainwater and their ability to hold water
underground, or in form of wetlands, and then slowly release it throughout the year is crucial.
the Sekhukhuneland Centre of Endemism.Ph.D. thesis,
University of Pretoria, Pretoria.
Internet Resources:
1. www.krugerpark.co.za/africa_pedi.html
2. www.encyclopedia.com/
3. en.wikipedia.org/wiki/Pedi_people
4. www.ezakwantu.com
5. www.dwa.gov.za/ORWRDP/Dehoop/index.asp
6. www.sekhukhune.gov.za/
7. www.sahistory.org.za/, South African History online
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DIE MAROELABOS VAN TSHIPISE-”DUIN” » Berig op volgende bladsy
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DIE MAROELABOS VAN TSHIPISE-”DUIN”
Die Maroelabos van Tshipise-”duin”
Die fyn, los, rooi sand waaruit die duinagtige
heuwel aan die suidoostekant van Tshipisekoppie
(Limpopo) bestaan is afkomstig van ‘n plaaslike
sandsteenformasie: “Dominantly red lithologies
characterise the Bosbokpoort Formation (Karoo
Group) which reaches a maximum thickness of
100 m in the Tshipise area. The lower part consists
of massive mudstone followed by siltstone which
occasionally grades into very fine sandstone.” (Brandl,
1981). Volgens mnr. N. Baglow van die Raad vir
Geowetenskap het die heuwel in situ deur verwering
van ‘n deel van hierdie formasie ontstaan (pers. med.).
Die rooi sand vorm ‘n dramatiese, skerp kontaklyn met
die grys sandsteenkoppie, wat daarop dui dat dit eens
onderhewig was aan verskuiwing. Die hele omgewing
is deurkruis van verskuiwingslyne.
Anders as wat ‘n mens sou verwag, is die maroela
(Sclerocarya birrea subsp. caffra) die dominante boom
op die heuwel. Soos uit Fig. 1 blyk, staan die maroelas
in digte, amper woudagtige, afsonderlike groepe op
die sand. Geassosieerde spesies is: Commiphoraspp.,
haak-en-steek (Acacia tortilis subsp.
heteracantha), fynblaarrooihout (Ochna serrulata),
sesambos (Sesamothamnus lugardii), helikopterspaanvrug
(Hippocratea longipetiolata), witrosyntjie
(Grewia bicolor) en kremetart (Adansonia digitata).
(Die vaal bossies in die oop dele tussen die bome is
die “doringblaarbossie” (Blepharis subvolubilis) met
hul pragtige blou tot ligpers blomlippe).
Die grootste maroelas staan teen die voet van die
heuwel (Figure 2 en 3). Hoër op word die bome al
hoe kleiner en armoediger (Figure 4 en 5), tot waar
sommige met hul dun, krom geboë stammetjies
nouliks meer beelddraers van die trotse maroelaspesie
genoem kan word (Fig. 6). In die winter verloor die
kruinbome ook hul blare ietwat voor die onderstes.
(Die foto’s is almal op 22 Junie 2011 geneem). Die rede
vir hul opsigtelike agterstand is waarskynlik die sand
se onvermoë om reënwater vir lang genoeg tydperke,
na behoefte van die bome, te behou. Die kruinbome
ly gevolglik makliker watergebrek as die basisbome.
Die maroela is ‘n bosveldboom wat op meerdere
grondtipes voorkom, bv. op sand, leemgrond en
selfs klipperige grond (maar nie op turf nie). Sy
eerste liefde is egter sand- of sandleemgronde (De
Winter e.a., 1966). In der waarheid staan die grootste
amptelik gemete maroela in Suid-Afrika op een van
die Springbokvlakte se sandbulte (Dendron 39:14-
Nico Hager
15). Dat maroelabome op ‘n sand-“duin” kan groei, is
daarom nie so ongewoon as wat ‘n mens geneig is om
te dink nie; die “duin” is immers sand en nie juis baie
hoog nie (30 m). Wat wel uitsonderlik is, is die bome
se verspreidingswyse in bykans homogene groepe,
teenstrydig met hul aard (Grant & Thomas, 2002)
(Figure 2-11). Waar die mens nie ingemeng het nie,
kom die maroela gewoonlik slegs yl verspreid tussen
dominante bome waarmee dit assosieer voor, bv.
knoppiesdoring (Acacia nigrescens) en wilde sering
(Burkea africana). Sy forse gestalte ten spyt, vind ‘n
mens hom selde in die rol van heerser. Vanwaar dan
sy onbetwiste gesag oor hierdie sandheuwel?
Fotos:
Nico Hager
Erkennings:
Dank is verskuldig aan mnr. Johan Blignaut van Forever Resorts,
Tshipise vir die gebruik van hul fasiliteite, aan mnr. Nick Baglow
van die Raad vir Geowetenskap vir inligting en aan prof. Braam
van Wyk van die Universiteit van Pretoria vir sy opbouende
kommentaar op die manuskrip.
Bronnelys:
BRANDL, G. 1981. The geology of the Messina area. Geological
Survey. Government Printer, Pretoria.
DE WINTER, B., DE WINTER, M. & KILLICK, D.J.B. 1966. Ses-ensestig
Transvaalse bome. Navorsingsinstituut vir Plantkunde.
Voortrekkerpers Beperk, Johannesburg.
GRANT, R. & THOMAS, V. 2002. Sappi tree spotting in Bushveld.
Jacana Education, Johannesburg.
Figure 1-12 is foto’s van die digte stande maroela (Sclerocarya
birrea subsp. caffra) wat op die rooi sandheuwel aan die
suidoostekant van Tshipisekoppie (Limpopo) staan.
Fig. 1: Gedeelte van die Tshipise-“duin”. Die heuwel is 1.03
km lank, 350 m breed en 30 m hoog. Die digte groen kolle is
maroelabome. Die dramatiese kontak van die rooi sand met die
grys sandsteen dui ‘n verskuiwingslyn aan.
Fig. 2: Basisbome
Fig. 3: Basisbome
Fig. 4: Hoërliggende bome
Fig. 5: Hoërliggende bome
Fig. 6: Armoedige kruinbome
Figure 7-11: Groepe maroelabome
Fig. 12: Sandheuwel en sandsteenkoppie word deur ‘n steil klofie
geskei. (Nie sigbaar op die satellietfoto nie). Soutpansberg in die
agtergrond. Rigting: suidwes.
FIG 1
FIG 4
FIG 7
FIG 10
FIG 2
FIG 5
FIG 8
FIG 11
29
FIG 3
FIG 6
FIG 9
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PALMBOME
Palmbome: Koninklike plante
Die belangstelling in palmbome grens soms
na aan dweepsug. Daar is waarskynlik nie
’n tuin in Suid-Afrika sonder ’n palmboom nie –
hoe groot of klein ookal die erf. Palmbome word
getakseer vir hul ornamtele asook kommersiële
waarde van sommige spesies.
Palms is houtagtige eensaadlobbige blomplante
wat aan die Arecaceae-familie (alternatiewelik
die Palmae) behoort. Die plante het almal ’n baie
kenmerkende groeivorm wat dit selfs vir ’n leek
maklik maak om te onderskei van ander plante.
Alhoewel hul nie verwant is aan die broodbome
(Zamiaceae-familie), die boomvarings
(Cyathaeceae-familie), Pandanaceae-familie,
kiepersole (Araliaceae-familie) en vlasplante
(Cordyline-familie) nie, kan hulle maklik met
mekaar verwar word.
Antieke lewensvorm
Palms is antieke lewensvorme en fossiel rekords
toon aan dat dit dateer uit die laat Kryt-tydperk
(circa 145.5 tot 65.5 miljoen jaar gelede) wat die
einde van die groot uitwissing en onder andere
die dinosaurusse aangekondig het. Omdat die
plante houtagtig is, is goeie fossielrekords gevind
en is dit nie onmoontlik dat dié plante selfs
nog vóór die Kryt-tydperk kon geleef het nie.
Ekologiese veranderings het sedert daardie tyd
wel plaasgevind en sien ons vandag dat spesies
in ander habitatte oorleef as waar die oorblyfsels
van fossiele oorspronklik gevind is. Stuifmeel van
byvoorbeeld die Nypa fruticans (moeraspalm) wat
vandag net in die trope voorkom is in sedimente
naby London ontdek.
Aantal spesies
Dit is ’n uiters ingewikkelde groep plante met
verskeie variëteite rondom ‘n basiese tema. Die
Sweedse plantkundige Carl von Linne (Linnaeus)
het die plante as die prins van plante gedoop.
Daar word tussen 210 – 236 palmfamilies en tussen
2 500 en 3 500 palmspesies in die wêreld erken.
Die verskil in die aantal families en spesies is te
wyte aan plantkundiges wat nie kan saamstem oor
die afbakening van families en van die spesies
nie. Palmbome is die vierde grootste groep
eensaadlobbige plante en daar word nog jaarliks
nuwe spesies ontdek. In Suid-Afrika is daar slegs
ses inheemse plamspesies, naamlik Phoenix
reclinata (wilde-dadelplam), Hyphaene petersiana
(Noordele-lalapalm), H. coriacea (lalaplam),
Naas Grové
Borassus aethiopum (Afrika-waaierpalm), Raphia
australis (Kosi-palm) en Jubaeopsis caffra (Pondpalm).
Die plante word selde in tuine aangetref met
met die uitsondering van die wilde-dadelpalm, wat
kommersieël redelik besikbaar is.
Algemene groei kenmerke
Palms is meerjarige, enkel- of tweeslagtige plante
met kenmerkende kroonblare. Dit plant deur middel
van saad voort. Meeste plante het ’n kenmerkende
bogrondse stam, met uitsondering van ’n paar
spesies wat ’n ondergrondse stam het. Alhoewel die
meeste palms ’n enkelvoudige stam het, is daar ’n
hele aantal wat kenmerkend meerstammig vanaf
die basis van die plant vertak. Die groeivorm staan
bekend as verklompte of saamgedronge stamme. By
die Licuala, Hyphaene, Ptychosperma, Gronophyllum
en Pinaga-spesies kom enkelstammige sowel as
verklompte groeivorms voor. Die blare van palms
is baie opvallend en het ’n baie kenmerkende
voorkoms. Blare is bykans sonder uitsondering
altyd aan die bopunt van die stam saamgedronge.
Meeste spesies se blare is handvormig of
veervormig saamgestel, maar een groep, Caryota,
het dubbelveervormig saamgestelde blare.
Slegs volwasse plante blom en by sommige spesies
kan dit op drie-jarige ouderdom plaasvind, terwyl
ander weer veertig jaar neem voordat dit wasdom
bereik. Sodra dit wasdom bereik het blom die meeste
plante jaarliks. Monokarpiese plante, waaronder die
inheemse Raphia australis (wilde-dadelplam), blom
slegs een keer in sy leeftyd waarna die plant vrek.
Meeste blomme is oninterresant, soms welriekend
en word deur insekte en deur die wind bestuif. Eenof
tweeslagtige blomme kom op afsonderlike plante
voor en by sommige spesies beide geslagte op
dieselfde plant in dieselfde blom.
Die vrugte is meestal klein en word in oorvloed gedra.
Die uitsondering is die kokosneut wat enkele groot
vrugte dra. Daar kom gewoonlik een tot drie, selde
meer as drie sade, in ‘n elke vrug voor.
Palms in die wêreld
Palms kom wyd verspreid regoor die wêreld, veral
in die tropiese dele, voor. Dit sal selde in baie droë
streke aangetref word. Die mees noordelike palm
Chamaerops excelsa kom bokant die 44˚N voor. ‘n
Variëteit van Rhopalostylis sapida is die palm wat
die verste suid op die Catham eiland, oos van Nieu-
Zeeland (44˚18’S) voorkom.
NOORDELE-LALAPALM Hyphaene petersiana » Foto: Naas Grové
Palms kan op verskillende hoogtes bo seespieël
aangetref word. Die Ceroxylon utile is die spesie
wat die hoogste bo seespieël in die Andes
gebergtes op ’n hoogte van 4 000m groei. Talle
spesies word by seevlak aangetref, maar ook
in woude waar die hoogte bo seespieël wissel
tussen 2 000 – 2 400m.
Ten spyte van die groot verspreiding en digtheid
van plams in die trope, is daar baie min families
wat wyd verspreid oor ’n groot area voorkom. Dit
is dus nie vreemd dat baie van die palm-families
endemies tot ’n streek is nie. Die vermoede is dat
palms oor die vermoë beskik om te evoleer en
sodoende by ‘n spesifike nis in die omgewing met
min moeite kan aanpas. So is daar byvoorbeeld
vier spesies palms wat aan drie families behoort
wat endemies is aan die Lord Howe Eiland in
die See van Tasmanië, ongeveer 600km oos van
die vasteland van Australië. In Fidji kom daar 22
palmspesies wat aan 10 genera behoort voor.
Bykans al dié spesies is endemies tot Fidji en vyf
van die families word net daar aangetref.
Palm habitat
Daar word bereken dat ongeveer twee derdes
van die palms van die wêreld in die reënwoude
voorkom. ’n Beduidende hoeveelheid kom egter
PALMBOME
ook voor in savanna grasveld en yl bebosde streke.
Meeste van laasgenoemde is geharde spesies wat
aangepas is by die droër omstandighede en kan dus
veldbrande oorleef. ’n Kenmerk van dié tipe palms
is dat waar hulle voorkom dit dikwels digte stande
vorm (Borassus, Livistona, Phoenix, Hyphaene en
Raphia). ’n Paar spesies het by spesifieke habitatte
en grondtipes aangepas waar hulle suksesvol met
ander plante om oorlewing kan meeding. Dit sluit
in gevalle waar dit langs kuslyne, vloedvlaktes,
moerasse, vleie en selfs in waterstrome kan oorleef.
Slegs een spesie, naamlik die moeraspalm (Nypa
fruticans) wat in Asië aangetref word groei in die
sagte modder van riviermondings. Die Ravenea
musicalis van Madagaskar oorleef in vinnig
vloeiende water van tot 2.5m diep. Enkele spesies
kan sneeu deurstaan soos Narrorrhops ritchiana in
die Afgaanse gebergtes en ’n spesie van die genus
Trachycarpus (windmeulpalms) wat in die Himalajas
aangetref word.
Baie min palms kan droogte weerstaan maar
enkeles kon aanpas, wat hulle toelaat om in
baie droë omstandighede te oorleef. Die plante
word egter meestal naby of langs permanente
waterbronne aangetref, of waar die watertafel baie
na aan die oppervlakte is. Die bekendste hiervan
tree stories
boomstories
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32
tree stories
boomstories
PALMBOME
is sekerlik die oase dadelpalm (Phoenix dactylifera)
wat kommersieël in verskeie dele van die wêreld vir
dadels gekweek word, ook hier in Suid-Afrika.
Eienaardighede van palms
Eienaardighede en talle interessanthede word
onder die groep plante aangetref. Dit
is nie algemeen bekend nie dat die
grootste saad, die langste blaar en
die grootste blom by palms aangetref
word. Die Lodoicea maldivaca (Dubbel
Kokosneutpalm) van die Seychelles
produseer reusagtige vrugte en een
enkele saad van die palm kan tot 20kg
weeg. Die langste blaar kom voor by die Sentraal
Afrika rafia-palm (Raphis regalis). ’n Rekord lengte
van 25.11m is aangeteken. Talle ander spesies van
die Raphia-genus het blare wat langer as 20m is.
Die reusagtige indrukwekkende kandelaaragtige
bloeiwyse van die Corypha umbraculifera (Talipotpalm)
wat in Indië aangetref word, kan tot tien
miljoen blomme per bloeiwyse op een slag
produseer! Uiterstes in die lengte onder die palms
kom ook voor, as ’n mens die kleinste palm met die
hoogste een vergelyk. Die dwergplam (Syagrus
lilliputiana) wat in Paraguay voorkom is skaars 15cm
hoog as dit volgroei is. Op die ander uiterste is die
Wasplams (Ceroxylon Quindiuense en C. alpinum)
van die Andes-gebergtes wat tot 60m hoog kan
word.
Bewaring van palms
Soos met die meeste plant- en dierspesies het
palms ook nie die vernietigingsdrang van die
mens vrygespring nie. Habitatvernietiging is
waarskynlik die een enkele grootste oorsaak wat die
voorbestaan van die oer-oue spesies bedreig. Dit is
veral grootskaalse ontbosting, mynbou-aktiwiteite,
self bestaan boerdery, degradasie van die grond en
erosie wat die groot sondebokke is. Ongelukkig is
dit nie die enigste bedreiging nie. Talle dele van
die plant word tradisioneel vir ’n verskeidenheid
gebruike aangewend. Die blare van Vetchia
montgomeryana en Pritchhardiopsis jeanneneyi
se status in die natuur is uiters skaars omdat die
blare vir ’n delikatesse in restourante aangebied
word. Die gebruik van die blare van die Kosipalm
vir weefwerk en vee voer, hou ’n soortgelyke
bedreiging in. In die noorde van Botswana en
Namibië word reuse bome Hyphaene petersiana
Ongeveer
nege
palmspesies
het al
uitgesterf.
(Noordele-lalapalm) jaarliks vir hul sap getap wat
as basis vir die brou van ’n lokale bier dien. Na drie
of vier jaar vrek die bome en is die uitgedroogte
stamme die enigste tekens wat oorgebly het van ’n
eens swierige plant.
Onoordeelkundige versameling van
saad deur versamelaars voeg nie veel
waarde toe nie. In die meeste gevalle
sal die saad nie ontkiem tensy die
medium waarin dit geplant word, die
natuurlike habitat kunsmatig naboots
nie.
Ongeveer nege palmspesies het al uitgesterf,
meestal as gevolg van menslike inmenging. Die
jongste toevoeging tot die lys was in 1985 toe die
Sabal miamiensis op die lys geplaas is as gevolg
van stedelike uitbreiding in die Amerikaanse staat
Florida. In Kuba het die Roystonea stellata uitgesterf
omdat die natuurlike habitat deur mense versteur is.
Die interessante Oase-palm van Egipte (Medemia
argun) is sedert 1964 nog nie weer in die natuur
opgemerk nie, en daar word vermoed dat dit ook
uitgesterf het.
Palms se ekonomiese waarde word na grasse hoog
aangeskryf. Talle gemeenskappe in die tropiese en
sub-tropiese dele van die wêreld se voortbestaan
is direk gekoppel aan die voorkoms van die plante.
Dit is wonderlike plante. Nie net vir hul skoonheid
en ornamentele prag wat dit aan ’n tuin verleen nie,
maar ook as potplante en kantoorversierings.
Bronnelys:
Johnston D. 1987. Conservation status of Wild Palms in Latin
America and the Carribean, Princeps 31 pp 96 – 97
Jones, DL. 1995. Palms throughout the World. Reed Books Australia
Langlois, AC. 1976. Supplement to Palms of the World. University
Press, Florida
Moore, HE (Jr). 1978. Endangerment of the specific and generic
levels in Palms. Princeps 23, pp 47 – 64
Tomlinson, PB. 1990. The structural biology of Palms. Clarendon
Press, Oxford
Internet
http://en.wikipedia.org/wiki/Arecaceae
http://www.2020site.org/trees/palm-tree.html
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• Mossel Bay to Storms River •
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like to get to know the trees of the Garden Route, whether
they are experienced botanists or amateurs.
The book contains information about 110 trees, including +
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have arrived at the right conclusion after identifying a tree with
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review
Mynbou in Limpopo provinsie
Die Dendrologiese Vereniging se rol
Verskeie mynbou en prospekteringsprojekte
in die Limpopo en Mpumalanga provinsies
het die afgelope twee jaar groot media-dekking
en protes van nie-regeringsorganisasies (NROs)
ontlok. Die mees bekende is die Vele-myn langs die
Limpoporivier en Mapungubwe Nasionale Park in
die noorde van die Limpopo provinsie. Onlangs het
prospektering deur dieselfde mynboumaatskappy
(Coal Africa) aan die noordelike hang van die
Soutpansberg ook voorbladnuus gehaal weens die
impak op beskermde plant- en dierelewe.
Velemyn het twee omgewingsimpakprosedures
ondergaan, waaraan vele NROs, insluitend die
Dendrologiese Vereniging deelgeneem het. Die
eerste omgewingsimpakstudie het oopgroef en
ondergrondse steenkoolontginning oor ‘n area van
8663 hektaar behels. Die Vereniging se belang
was eerstens by die grootskaalse vernietiging van
bosveldbome in ‘n area wat ge-oormerk is vir ‘n
Oorgrens Nasionale Park, en die moontlike impak
van die myn op rivier-oewerwoud. Vyf beskermde
boomspesies sou geraak word (maroela, hardekool,
kremetart, witgat en appelblaar). Die Vereniging
het geregistreer as belanghebbende instansie en
‘n brief gerig aan die konsultante waarin kommer
oor die beoogde mynbou-aktiwiteite se potensiële
impakte uitgespreek is. Die mynbou kan deur
water ontrekking, stofneerslag wat fotosintese
inhibeer en grondwaterbesoedeling ‘n nadelige
impak hê op bome in die rivieroewerwoud en
langs dreineringslope wat die Limpopo voed.
Nieteenstaande is omgewingsgoedkeuring verleen
vir die beoogde mynbou.
Coal Africa moes ‘n tweede omgewingsimpakstudie
onderneem om infrastruktuur by die Velemyn
te vestig, insluitend toegangspaaie en
steenkoolstoorareas. Die myn het in 2010 onwettig
met die infrastruktuurontwikkeling begin sonder
omgewingsgoedkeuring. Die Dendrologiese
Vereniging se bestuur het die gebied laat in 2010
besoek en het saam met ander NROs bygedra tot
die Groen Skerpioene se ondersoek deur uit te wys
watter beskermde boomsoorte onwettig verwyder
is. Die Departement van Landbou, Bosbou en
Visserye het ‘n lisensie vir die kap van beskermde
bome toegestaan vir die mynboufase, maar nie vir
die infrastruktuurontwikkeling nie. Daar is aan die
owerhede uitgewys dat Coal Africa die aanvanklike
Redakteur - namens die Sentrale Komitee
lisensie ook verkeerdelik voorgehou het as geldig
vir die infrastruktuur ontwikkeling. Wat nog meer
is, daar is skade aangerig aan ‘n klein deel van die
rivieroewerwoud, wat beskerm is onder die Boswet.
Wat die nuwe beoogde myn aan die noordelike
hang van die Soutpansberg betref is ‘n lisensie
uitgereik vir die verwydering van ‘n beperkte aantal
beskermde boomsoorte, insluitend hardekool en
kremetart vir prospektering. Die steenkool wat by
die prospekteringsarea uitgehaal word is na die
Sasolaanleg in Gauteng vervoer om die gehalte
daarvan te toets. ‘n Omgewingsimpakstudie sou nog
gedoen word vir die beoogde mynbou indien die
gehalte daarvan voldoende is.
Die teenkanting teen die mynbou word gelei
deur NROs soos die Natuurlewe Vereniging wat
op finansiering van borge steun en permanente
personeel in diens het. Die Dendrologiese Vereniging
word op ‘n ander wyse bedryf en met ‘n beperkte
fokus op bome en boomoorheersde-ekosisteme,
beskik die Vereniging nie oor sodanige bronne en
personeel nie, en gaan dus ietwat anders te werk. Dit
is eerstens geskoei op die bewusmakingselement
en bevordering van die boomwetenskap, en op
meelewing van mense met soortgelyke belange deur
middel van uitstappies. Die rol wat die Vereniging
begin speel het in omgewingsimpakstudies het maar
onlangs begin, met die toenemende aanslag van
ontwikkeling in natuur gebiede. Die Vereniging is
nie gekant teen ontwikkeling per se nie, maar glo dat
dit op gebalanseerde wyse moet geskied, en nie in
sensitiewe gebiede nie.
Die Vereniging kan net by die mees kritieke gevalle
wat bome en boomvelde raak betrokke wees, omdat
deelname aan omgewingsimpakstudies baie tyd verg,
en die Vereniging nie oor hulpbronne beskik wat in
hul vrye tyd nog aktief daaraan kan deelneem nie.
Deelname is ook ‘n sensitiewe kwessie, en indien
individue of takke onder die Vereniging se naam
opinies in die openbaar sou lug of briewe sou skryf
kan daar potensiële skade aan die Vereniging se
beeld gerig word indien sodanige opinies of briewe
nie weldeurdag is nie. Daarom moet standpunte en
skrywes deur die Sentrale Komitee uitgereik, of deur
die Sentrale Komitee ondersteun word alvorens dit
openbaar gemaak word.
MYNBOU IN LIMPOPO PROVINSIE
VERNIETIGING VAN DIE MOPANIEBOS NABY MAPUNGUBWE » Foto Naas Grové
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CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
Classification and nomenclature
of the genus Acacia (Leguminosae), with emphasis on Africa
Abstract
The widespread and well-known genus Acacia
has experienced a huge amount of taxonomic
turmoil over the past couple of decades. In this
contribution the nomenclatural history of Acacia is
outlined. Evidence for the recent split of the genus
into five segregate genera is provided and the
retypification from the African species A. nilotica to
the Australian A. penninervis is discussed critically.
The International Code for Botanical Nomenclature
(ICBN) is introduced and discussed as a set of
guidelines for taxonomic change. Lastly, some ideas
are provided for plant name users of how to deal
with this nomenclatural inconvenience.
“No other taxonomic proposal
has ever had the potential for
disruption to nomenclature on a
continental scale as the one to split
Acacia.” – Orchard & Maslin 2005
1. Introduction
Convincing evidence has been accumulating
over the past two to three decades that the large,
well-known and charismatic genus Acacia Mill. is
polyphyletic (Maslin et al. 2003; Orchard & Maslin
2003). Polyphyletic refers to a group derived from
different common ancestors. The ideal in plant
classifcation is to recognize monophyletic groups.
In the case of a monophyletic group all members
are derived from the same recent common ancestor.
Many taxonomic workers now agree that Acacia
senso lato (as traditionally defined), meaning Acacia
in a broad sense, should in fact be five segregate
genera, because five separate monophyletic groups
can be recognised within the genus (Maslin et al.
2003). In 2005 the genus was split and retypified
in accordance to Proposal 1584 by Orchard &
Maslin (2003). This caused a plant nomenclatural
uproar, the likes of which had never been seen and
hopefully will never be seen again. The aim of this
contribution is to review the developments in Acacia
s.l. phylogeny and its impacts on the classification
and the nomenclature of the group, with emphasis
on Africa. I will further attempt to critically evaluate
the split and retypification of the genus and provide
William a. Haddad
some thoughts on how to cope with this great
nomenclatural inconvenience.
2. Background on the genus Acacia
Although the palaeobotanical evidence is
inconclusive, it is generally believed that the genus
Acacia s.l. evolved in the tropical lowland forests
of West Gondwana, but there is no agreement as
to which section should be considered ancestral.
The various sections in existence today must
have evolved from the original form in secondary
centres where the climatic or edaphic factors
were different (Ross 1979). The oldest Acacia s.l.
fossil was found in Tanzania and dated at 46 mya
(Bouchenak-Khelladi et al. 2010).
The highly complex nomenclatural history
(outlined in Table 1) of the genus Acacia s.l.
started with its formal description by Phillip
Miller in 1754. It was not until 1842, however, that
the generic limits were clearly defined by George
Bentham by restricting the name to mimosoid
plants with numerous free stamens (Maslin et
al. 2003). The genus was only typified in 1913
by Britton and Brown to the African species A.
scorpioides (L.) W.Wight (=A. nilotica (L.) Delile).
Since that time many authors have proposed
different ways to subdivide the genus, making use
of various different characters (Bentham 1875;
Ross 1979; Vassal 1981; Pedley 1986; Orchard &
Maslin 2003).
Acacia, in the broad sense, is the second largest
genus in the family Leguminosae (Fabaceae s.l.)
or the largest genus in the family Mimosaceae,
if considered under an alternate classification
system, with about 1540 living taxa (specific
& intra-specific)(Orchard & Maslin 2005). It is
widely distributed across the world’s tropics and
sub-tropical zones with centres of diversity in
Australia (± 1000 species), the Americas (±180
species), Africa (± 160 species), Asia (±100
species) and a couple of species on the Pacific
Islands (Thiele et al. 2011) (Figure 1). As of yet,
there are no explanations for this remarkably
disjunct geographic distribution (Bouchenak-
Khelladi et al. 2010). Ross (1979) describes the
ecological role of Acacia s.l. very satisfactorily:
“There is probably no group of trees or shrubs
in Africa that can rival Acacia in the combined
importance of its ecology and extent of its
geographical range. Almost everywhere from
South Africa northwards to the Mediterranean,
where the climate is reasonably dry, there will
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
Year Nomenclatural Event Key Reference
1754 Genus Acacia described. Miller (1754)
1842 Generic limits defined
1875 Considered one genus with six series. Bentham (1875)
1913 Genus Acacia typified to A. nilotica.
1981 Considered as one genus with three subgenera. Vassal (1981)
1986 Proposal to raise subgenera to three individual genera. Pedley (1986)
2003
Proposal 1584 to split genus into five genera and to move the type of
name Acacia to A. penninervis.
Orchard & Maslin
(2003)
2004 The IAPT Committee for Spermatophyta recommends proposal 1584. Brummitt (2004)
2005
2011
Proposal 1584 is controversially accepted at the nomenclature
section of the 16th IBC in Vienna. The type is moved and five different
genera are now recognized.
An attempt is made at the 17th IBC in Melbourne to overturn the
decisions made in Vienna. The attempt failed and the type remains an
Australian species.
TABLE 1.– Simplified nomenclatural history of the genus Acacia.
180
160
Acacia be found, usually frequently and often in
dominant abundance. Only in the evergreen forest
regions of Africa do Acacia play a comparatively
subordinate role”.
100
1000
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FIGURE 1.– Distribution map showing the range of Acacia s.l. with approximated numbers of endemic taxa
per continent. Image from www.worldwidewattle.com and data from Thiele et al. (2011).
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The traditional classification of Acacia s.l. was based
mainly on the ideas of Bentham (1875) who considered
it to be a single genus, containing six series. The most
widely used recent classification is that of Vassal
(1981)—one genus, three subgenera (see Table 2).
In 1986 Pedley proposed that the three subgenera
should each be raised to generic rank, namely
Acacia, Senegalia Raf. and Racosperma Mart. (Table
2), but taxonomists have been reluctant to accept
this classification because of an apprehension of the
nomenclatural turmoil that it would entail (Orchard
& Maslin 2003). Recent taxonomic work done on
the genus and its relatives in the tribes Ingeae and
Mimoseae have greatly expanded our knowledge of
the groups, however (Maslin et al. 2003). This includes
evidence from morphology, palynology, biochemistry,
molecular and cladistic studies and led to a general
Pre- Vienna ICB names
(A. nilotica as type)
Acacia
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
Pedley’s classification
3. Role of the ICBN
It is important at this stage, before we continue to
the discussion on the modern controversies around
the name Acacia, to define clearly the terminology
used in the field of systematics. According to the
13 th Edition of Henderson’s dictionary of biology
(Lawrence 2005), systematics is the study of the
identification, taxonomy and nomenclature of
organisms, including the classification of living things
with regard to their natural relationships. Taxonomy
is the analysis of an organism’s characteristics for
the purpose of classification, whereas classification
is the arrangement of living organisms into
groups on the basis of observed similarities and
differences. Most modern classification systems
try to reflect degrees of evolutionary relatedness
(Lawrence 2005). Identification is the process of
associating an unknown taxon with a known one or
the recognition that the unknown is new to science
and the assignment of names using a formal system
belief among taxonomic workers that Acacia s.l.
should in fact be five segregate genera (Orchard &
Maslin 2005).
In 2005 Orchard & Maslin described these five
groups as follows (Table 2): “The largest of these,
with about 960 species is the current A. subg.
Phyllodineae (DC.) Ser. (= subg. Heterophyllum
Vassal), for which the name Racosperma is available.
The next largest is A. subg. Aculeiferum Vassal with
about 203 species, and for which the name Senegalia
is available. The third major group, presently known
as A. subg. Acacia, contains about 161 species,
including the current type of Acacia, A. nilotica.
The name Vachellia is available for this group. The
remaining two groups are small and compromise 15
and 13 species respectively.” These last two smaller
groups arise from within A. subg. Aculeiferum.
With retypification
(A. penninervis as type)
Post- Vienna ICB names
Without retypification
(A. nilotica as type)
subg. Acacia Acacia Vachellia Acacia
subg. Aculeiferum Senegalia
sect. Spiciflorae Senegalia Senegalia
sect. Filicinae Acaciella Acaciella
A.coulteri group Mariosousa Mariosousa
subg. Phyllodineae Racosperma Acacia Racosperma
TABLE 2.– Summery of the various classification systems used for the genus Acacia s.l.
is called nomenclature (Simpson 2006).
Scientific nomenclature allows people to
communicate about organisms and to store and
retrieve information about these organisms.
Simpson (2006) summarises the need for names
well: “Botanical names serve as symbols of a group
of natural entities for the purpose of communication
and data reference.”, while the preface to the 2005
International Code for Botanical Nomenclature
(ICBN) (available at http://ibot.sav.sk/icbn/main.
htm) states that “Unambiguous names for organisms
are essential for effective scientific communication
(and) names can only be unambiguous if there
are internationally accepted rules governing their
formation and use.” Nomenclature and classification
systems are working tools and should be as stable
as possible, because if it changes continually, it
will cease to be meaningful. Taxonomists, however,
have been criticized for changing too many things
too often (Orchard & Maslin 2005). In an attempt
to stabilize and regulate plant nomenclature, the
International Code for Botanical Nomenclature
(ICBN) has been developed over decades in order
to try to increase stability of names. Several articles
of the code have been designed and incorporated
specifically to help facilitate the conservation of
names in order to minimise name changes (see Box
1 for examples of conserved names in use today).
Conserved Name Reason for Conservation Key Reference
Hedysarum
(Leguminosae: Papilionoideae)
Leucaena
(Leguminosae: Papilionoideae)
Centaurea
(Asteraceae)
Bossiea
(Leguminosae)
Research showed that the name
Hedysarum would be restricted to
H. subg. Hedysarum, containing
only six species. A new name will
then be required for the remaining
members of Hedysarum s.l.—
approximately 100 species.
Leucaena was conserved to a new
type when it was discovered that
the basionym of the previously
accepted type belonged to
Acacia. This would have caused
Leuceana to become a synonym
of Acacia.
The accepted type of Centaurea
was discovered to belong to a
small group of about 32 species
earmarked for segregation to
Bielzia. The remaining 400–700
species thus needed new names.
Bossiae (59 spp.) and Platylobium
(4 spp.) are to be merged, but
Platylobium has priority of
publication. The conservation of
Bossiae would thus be better for
nomenclatural stability.
BOX 1.– Examples of other successfully retypified and conserved names.
4. Evidence for splitting the genus
It has long been known, or at least strongly suspected,
by many taxonomic workers that the genus Acacia s.l.
is polyphyletic (Pedley 1986; Orchard & Maslin 2003).
This means that the genus is actually an artificial
construct consisting out of several fairly unrelated
genera. While the majority of Acacia s.l. species are
characterized by numerous free filaments, there
are no synapomorphic characters that support their
positioning as a natural group (Kergoat et al. 2006). The
current view is that the group should be divided into
five separate genera in order to satisfy the requirement
of monophyly. In the following subsections, evidence is
provided for the five genera point of view.
4.1 Established evidence
The idea that Acacia s.l. is not a homogeneous
group is not new. A 1979 review by Ross outlined
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
The ICBN regulates primarily two basic activities,
namely (1) the naming of new, undescribed or
unnamed taxa and (2) correctly renaming previously
named taxa which have been divided, united,
transferred or changed in rank. It is this second
activity that we are interested in in this case, as the
genus Acacia has been changed in rank.
Choi & Ohashi (1998)
Hughes (1997)
Greuter et al. (2001)
Ross (2004)
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review
many differences between the two mainly African
subgenera of Acacia s.l., based on morphology,
palynology, genetics, anatomy and biochemistry
(Table 3). It is expected that there would be an
even number, if not greater number, of differences
between the African and Australian subgenera
based on these criteria, but literature on this could
not be accessed.
It is easy to see how these groups could have been
lumped together for so long. Consider for example
the thorns: One can easily mistake the presence
of thorns in both groups as a common character,
but on closer inspection it turns out that they are
not homologous. In Vachellia the thorns are in
fact spines derived from the stipules, where as in
Senegalia, they are prickles derived from epidermal
outgrowths. These two seemingly similar characters
thus represent a very different evolutionary history.
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Morphology
Vachellia
1. Capitate inflorescences (bright golden yellow with
some pale-yellow to white).
2. Stipules spinescent.
3. Seeds with large areoles that conform to the
outline of the seed shape.
4. Development of fascicular secondary leaves.
5. Inflorescences have an involucel on the peduncle.
6. Ovaries sessile or sub-sessile with no disc
(nectary).
7. Floral bracts persist to seed set.
8. Pod pericarp consists of only longitudinal fibres,
or is absent.
9. Differences in pod venation.
Palynology
10. Pollen grain with furrows on the surface.
anatomy
11. Differences between petioles.
12. Differences in ontogeny of stipule tissues.
13. Anatomy of leaflet tissue types differ.
14. Differences between seed coats.
Genetics
15. Diploid chromosome number of 2n=52.
16. Differences between nucleolar diameters and
chromatin lengths.
Biochemistry
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
17. A very distinctive amino acid distribution found in
the seeds.
18. Seeds contain unusual amino acids that are not
present in the other group.
19. Gum has a higher molecular weight-viscosity than
the other group.
20. Heartwood has flavonoids of the resorcinol A-ring
group.
Morphology
Senegalia
1. Spicate inflorescences (pale-yellow to white
flowers).
2. Stipules non-spinescent.
3. Seeds with small horseshoe-shaped central
areoles.
4. No development of fascicular secondary leaves.
5. Inflorescences do not have an involucel on the
peduncle.
6. Pedicellate ovaries with a cup shaped disc
(nectary).
7. Floral bracts shed before flower opens.
8. Pod pericarp consists of longitudinal and
latitudinal fibres.
9. Differences in pod venation.
Palynology
10. Pollen grains without furrows on the surface.
anatomy
11. Differences between petioles.
12. Differences in ontogeny of stipule tissues.
13. Anatomy of leaflet tissue types differ.
14. Differences between seed coats
Genetics
15. Diploid chromosome number of 2n=26.
16. Differences between nucleolar diameters and
chromatin lengths.
Biochemistry
17. Not a distinctive amino acid distribution in the
seeds.
18. Seeds contain unusual amino acids that are not
present in the other group.
19. Gum has a lower molecular weight-viscosity than
the other group.
20. Heartwood has flavonoids of the pyrogallol A-ring
group.
TABLE 3.– Differences between the two mainly African groupings of Acacia s.l. now known as Vachellia
and Senegalia, as summarized by Ross (1979). (Exceptions to these trends exist, but they are few and
many can be explained as hybridization events or recent convergence.)
4.2 Recent evidence
The evidence in Table 3 was not enough, however,
to convince people to take up classifications splitting
Acacia s.l. into different genera (such as that of Pedley
(1986)). It is only recently that the world of systematics
has become more inclined to embark upon the
huge taxonomic endeavour of splitting this large
genus—fuelled primarily by a large quantity of sound
phylogenetic evidence using molecular markers
(Kergoat et al. 2006).
Probably the most comprehensive phylogenetic study
done on the acacias and its relatives in the tribes
Acacieae, Ingeae and Mimoseae, is that of Bouchenak-
Khelladi et al. (2010). They found that Mimosoideae is
monophyletic, but that the distinction between the taxa
within this subfamily is not well defined and should be
investigated further. In addition, they found that the
tribe Mimoseae is paraphyletic because Vachellia, a
member of the tribe Acacieae, nests within it. This led
them to believe that, despite being characterized by
synapomorphic characters, the tribe does not share
a common ancestor. Vachellia, Senegalia, Mariosousa
and Acaciella are all supported as monophyletic
groups, but Vachellia is considered to be basal while
Senegalia, Mariosousa and Acaciella are more derived
and representative of early-diverging lineages from
the Ingeae and Acacia s.s. clade. Although their
phylogenetic relationships are not yet resolved, the
tribe Ingeae and Acacia s.s. form a monophyletic
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group. All these relationships are illustrated in Figure
2, a simplified version of the phylogenetic tree by
Bouchenak-Khelladi et al. (2010).
Kergoat et al. (2006) attempted to use alternative
sources of information to provide additional insights
into Acacia s.l. systematics. They argued that
phytophagous insect species that are obligate feeders
on a restricted number of host plant taxa should display
a similar evolutionary pattern to that of the host plant.
This pattern is termed ‘taxonomic conservationism in
host plant use’. Kergoatet al. (2006) was particularly
interested in the specialized seed-beetles or Bruchid
beetles (Coleoptera, Chrysomelidae, Bruchinae)
because they generally exhibit a strong level of
taxonomic conservationism in host-plant use and are
known to develop in Acacia s.l. seeds.
It was found that species of the bruchid genera
Acanthoscelides, Mimosestes and Bruchidius clade
II are preferentially associated with Vachellia and
members of the tribes Cassieae and Ceasalpinieae.
Species of Merobruchus feed almost exclusively on
Acacia s.s., Acaciella, Mariosousa and Senegalia as
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
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well as members of the tribe Ingeae. Lastly, Stator
and Bruchidius clade I species are able to feed on a
much larger set of host plants including both Vachellia
and other Acacia s.l. species (Kergoat et al. 2006).
The phylogeny of Mimosoideae seed predators thus
support the phylogeny depicted in Figure 2 and the
idea that Acacia s.l. is paraphyletic. Some groups of
beetles are associated only with the basal Vachellia,
Cassieae and Ceasalpinieae, while others are
associated with the more derived Acacia s.s., Acaciella,
Mariosousa, Senegalia and Ingeae.
Further noteworthy observations from the Kergoat
et al. (2006) study are that the patterns of host-plant
associations seem to be strongly mutually exclusive.
In other words, predators that feed on Vachellia
and Ceasalpinieae seed will not feed on Acacia
s.s., Acaciella, Mariosousa and Senegalia seed and
vice versa. Also, species of seed predators that are
associated only with Vachellia are closely related,
suggesting a conservative host shift to the genus.
From all the above mentioned evidence it is thus
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CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
clear that Acacia s.l. is a very heterogeneous group
and that it would make sense to divide it into five
more homogeneous genera, because it would greatly
improve the stability and predictive capabilities of
the classification system. The split would however
negatively affect our ability to access information on
the taxa that now use new names, because a name
acts as a key to accessing information. But over time
and with the correct use of synonyms, this problem
will become less pronounced. Moving the type
specimen from the African A. nilotica to the Australian
A. penninervis, however, was a much more contentious
and hotly debated proposal. The argument for and
against this move is discussed in the next section.
Acacia s.s
Ingeae
Acaciella
Mariosousa
Senegalia
Mimoseae
Vachellia
Mimoseae
Caesalpinieae
FIGURE 2.– Simplified phylogenetic tree of the
five genera within Acacia s.l. and tribes Ingeae,
Mimoseae and Caesalpinieae. Adapted from
Bouchenak-Khelladi et al. (2010).
5. Retypification
Splitting the genus Acacia into five segregate genera
means that only one of the five newly delimited
genera can keep the generic name of Acacia.
Post-Vienna ICB names
(A. penninervis as type)
According to the ICBN the group that contains
the type specimen of the name gets to keep that
particular name. In the case of Acacia, the generic
type was A. nilotica, a member of A. subg. Acacia,
containing ca 160 taxa. This meant that once the
genus was split, only some 12% of the more than
1400 species of Acacia s.l. will still be able to use
the name (see Table 4). Orchard and Maslin (2003)
proposed to move the generic type specimen of
genus Acacia to a member of the largest splinter
group, A. penninervis of the subg. Phyllodineae. This
would ensure that about 72% of the original Acacia
s.l. species can keep using the name Acacia. When
just considering pure numbers, retypification looks
like a brilliant idea and it is difficult to think how
anyone can disagree with it, but the retypification of
Acacia was probably one of the most hotly debated
issues in modern plant taxonomy. See also Box 1
for other examples of retypification and Table 1 for
dates of retypification.
As a result of the generic split, about half of Africa’s
thorn trees will become Senegalia. The contest for
use of the generic name Acacia is thus restricted
to A. subgenera Acacia and Phyllodineae. Because
A. subg. Phyllodineaea has a near exclusive
Australian distribution and A. subg. Acacia is
strongly associated with especially Africa, but also
South America, this became an ‘Australia versus
the rest of the world’ debate. Most of the arguments
for and against retypification are summarised in
Table 5 while some of the more important ones are
discussed in more detail below.
Retypification is a well tried and accepted procedure
allowed by the ICBN and the precedent exists that
the name of a large genus should be conserved to
advance nomenclatural stability in such cases (see
Box 1 for examples). Luckow et al. (2005) however
argue that each case should be examined carefully, in
particular the impact on the taxon that stands to lose
Sp. numbers and distribution
Americas Africa Asia Australia Total
Vachellia 52 83 32 9 163
Senegalia 79 74 48 2 194
Acaciella 15 0 0 0 15
Mariosousa 13 0 0 0 13
Acacia 0 1 12 1017 1021
Total 161 158 92 1028 1406
TABLE 4.– Species numbers of Acacia s.l. members corresponding to geographic areas of major
occurrence. Adapted from Thiele et al. (2011).
CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
PAPER-BARK THORN, Acacia sieberiana subsp. woodii – LESHIBA WILDERNESS » Photo: Naas Grové
the use of the original type. They quote from a paper
by McNeill et al. (2003) on the conservation of names:
“Committees will not be sympathetic to proposals to
avoid disadvantageous change in usage in one part of
the world at the expense of creating disadvantageous
change in another. These situations are what the
principles of priority are for”. Basically, Luckow et
al. (2005) said that with such a controversial, evenly
contested and emotionally loaded question, such as
that of Acacia, the principle of priority should prevail.
The argument for or against retypification should not be
based purely on numbers, but the share of the world’s
population that would be affected by such changes
should also be considered. Although Acacia s.s. is very
speciose and contains about 72% of Acacia s.l. taxa,
the majority of these species are narrow endemics,
while Vachellia has a much wider distribution (Luckow
et al. 2005). Thus the change to Vachellia will affect
more people in more countries around the world than
the change to Racosperma will, even if there are about
six times more taxa in Racosperma than Vachellia.
Orchard & Maslin (2005) are of the opinion that gross
numbers are very important, irrespective of the
distribution of individual taxa. They argue that while
widespread species may impact on more floras, rare
species will feature much more widely in conservation
literature and legislation.
Another important focal point in the argument for
or against retypification was that of economic and
ecological importance of the two groups in question.
review
review
Many acacias of economic importance are of the subg.
Phyllodineae and are grown in more than 70 countries
where they are estimated to cover over 2 million
hectares in commercial plantations (Orchard & Maslin
2003). There are thus many countries, industries
and activities that are affected by the change to
Racosperma. Weed management, floriculture, forestry
(timber, pulp, tannins and fuel wood) agriculture and
land rehabilitation to name a few. In terms of ecological
importance, it is very difficult to compare two different
groups from two different continents with one another.
There are many varied views in the literature as
to which group is more important to its respective
continent, but I am of the opinion that we cannot make
such a call based on current knowledge.
Lastly, an often over looked fact is that the use of
Racosperma would be unfortunate as the gender will
change from feminine (Acacia) to neuter (Racosperma)
and this will affect the specific epithets. For example:
Acacia adunca would become Racosperma aduncum
and users that are not familiar with Latin (which I am
pretty sure includes most users) will be tempted to
‘correct’ it to Racosperma adunca (Orchard & Maslin
2003). The use of Vachellia and Senegalia necessitate
no gender changes as both are feminine.
The retypification issue of Acacia was a very evenly
contested debate and both side presented very
convincing arguments, but the battle has been fought
and a conclusion has been reached. Whether it was
the best route to follow or not, only time will tell.
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CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
Arguments for Retypification
• Retypification allows for the conservation of some 72% of Acacia s.l. names. Thus greater
nomenclatural stability.
• Because Acacia s.s. contains many rare and endangered species, it is argued that a change to
Racosperma would have a severe impact on conservation literature and legislation.
• If Racosperma is adopted, the gender would change from feminine (Acacia) to neuter
(Racosperma).This will affect the termination of the specific epithet. The use of Vachellia and
Senegalia necessitate no gender changes as both are feminine.
• Because about half of Africa’s acacias are changing their names to Senegalia anyway, it would be
better and less confusing if all the naturally occurring acacias just change their names.
• Africa, Asia and the Americas will have to change their floras to accommodate Senegalia anyway.
• Australian species of Acacia are naturalized in many other parts of the world and will still impact
their floras if it is changed to Racosperma.
• The official floral emblem of Australia is that of an Acacia s.s.
• Acacia s.s. constitutes the largest genus of flowering plants on the Australian continent.
• Ecologically significant in Australian ecosystems.
• More Australian species are of global economic importance than African species.
• The Australian group is less likely to be subject to further generic splitting.
Arguments against Retypification
• No retypification will restrict the use of the name Acacia to about 12% of Acacia s.l. taxa.
• Retypfication and conservation of genus Acacia to an Australian type will impact many regional
floras around the globe.
• Retypfication and conservation of Acacia will impact a much larger part of the global population,
because Acacia s.s. has a relatively small global distribution when compared to Vachellia.
• Many species of Acacia s.s are narrow endemics and changing the names of narrow endemics has
a much smaller impact than changing the names of species with wide distributions.
• Retypification will benefit ca 20 million people in one country at the expense of over a billion
people in about 90 countries.
• Australian acacias are more commonly known as “wattles” and many will not connect it with
Acacia. Acacia, however, is used throughout Africa and Latin America as a common name.
• Many developing countries will be affected by the retypification, while it only benefits one
developed country.
• Retypification increases the already big economic burden of related name changes placed on
many developing countries.
• The ICBN’s guidelines for conservation of names will be violated by the retypification. It states
that the principle of priority should prevail when conservation for one part of the world creates a
disadvantageous situation in another part of the world.
• Retypification and conservation undermines the rules and guidelines of the ICBN, the principle of
priority in particular. This sets a bad precedent and erodes the authority of the ICBN.
• New combinations in Racosperma have been made for the vast majority of Australian species,
while only four combinations have been made in Vachellia (data current in 2005).
• Public perception of Acacia is that of a flat-topped tree in the African savannah.
• Most species of Vachellia are keystone species in their ecosystems.
• Recent split of Cassia into three genera: No one seems to be unhappy with the application of that
name to the smallest of the three genera.v
TABLE 5.–Summary of the argument presented for and against the retypification of Acacia. Information
compiled from Orchard & Maslin (2003); Luckow et al. (2005); Brummitt (2004) and Thiele et al. (2011).
Conclusion
The literature of such a large and ecologically
dominant genus such as Acacia s.l. is enormous and
any changes of nomenclature, be it to Vachellia or
Racosperma, is sure to have profound repercussions.
It will probably take several generations for the new
classification to be widely used and who knows if it will
still be considered current at that time. It is comforting
to know, however, that the ICBN does not prescribe
which classification system to use—that choice lies
References
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BOUCHENAK-KHELLADI, Y., MAURIN, O., HURTER, J. & VAN DER
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northern United States, Canada and the British possessions, vol.
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BRUMMIT, R.K. 2004. Report of the committee for
Spermatophyta: 55. Proposal 1584 on Acacia. Taxon 53: 826–829.
CHOI, B.H. & OHASHI, H. 1998. (1377) Proposal to conserve
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GREUTER, W., WAGENITZ, G., AGABABIAN, M. & HELLWIG,
F.H. 2001. (1509) Proposal to conserve the name Centaurea
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HUGHES, C. 1997. (1297) Proposal to conserve the name
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KERGOAT, G.J., SILVIAN, J., BURANAPANICHPAN, S. & TUDA, M.
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for paraphyletic genus Acacia from the systematics and
host-plant range of their seed predators. Zoologica Scripta 36:
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CLASSIFICATION AND NOMENCLATURE OF THE GENUS ACACIA
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with the end users of plant names and they now have
the opportunity to choose whether they want to use
the name Acacia in the strict or broad sense (Smith et
al. 2006). I will conclude this review (which has only
but scratched the surface) on the classification and
nomenclature of the genus Acacia s.l. with the following
ironic thought: After retypification, a group of plants
that do not have prominent thorns or spikes now lay
claim to the exclusive use of the name Acacia, derived
from the Greek word Akis, meaning sharp point.
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MCNEILL, J., REDHEAD, S.A. & WIERSEMA, J.H. 2003. Guidelines
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UNDERGROUND TREES OF THE PONDOLAND CENTRE
Underground trees of the Pondoland Centre
The term ‘underground trees’ evocatively
presents a picture in one’s mind, perhaps of
a baobab buried deep in the ground, with just its
branch tips showing above the surface. Well now,
this is not quite how it is, but the concept is pretty
close. First the history, and there is not too much of
that. In 1922, Joseph Burtt Davy [1870–1940] wrote
a paper entitled ‘The suffrutescent habit as an
adaptation to environment’. Burtt Davy was quite a
remarkable fellow; he was born in England, worked
at Kew and later in California, having by then studied
both botany and agriculture. In 1903 he joined the
Transvaal Department of Agriculture and in 1925,
finally went as a lecturer at the Imperial Forestry
Institute, Oxford. This twofold academic training
together with his experiences in different parts of
the world gave him a solid feel for plant ecology.
In his paper Burtt Davy presents some possible
reasons for the evolution of what are now called
geoxylic suffrutices (singular: geoxylic suffrutex) or
“geosuffs”, a term coined by Marita Thornhill and
Ian Felton in their article in PlantLife No. 23. The
term ‘geofrutex’ is also occasionally encountered as
a synonym in the literature but I prefer geosuff.
According to the references I have, definitions of
suffrutex and geoxylic are: an undershrub (Jackson
1971): half shrub, sub-shrub, perennial plant with
only the lower part woody (Stearn 1983). The only
reference to “geoxyl” says: having a woody stem,
partly hypogeic (growing on or remaining below
ground), partly epigeic (spreading above the
surface (Jackson 1971).
Frank White [1927–1994], Curator of the Forest
tony abbott
Herbarium and Lecturer in Systematic Forest
Botany at Oxford University, held a lifelong interest
in the woody plants of southern Africa and was
renowned for his knowledge and work on the
vegetation of sub-Saharan Africa. White was the
next to look in more detail at this phenomenon and
in 1976 published his now classic paper on the
‘Underground Forests of Africa’. Here he suggests
that in many African grasslands, in particular those
of shallow wetlands and floodplains (‘dambos’) in
south-central Africa, the underground biomass of
‘underground trees’ exceeds that of the associated
grasses. He describes these peculiar ‘trees’ as
having massive woody underground parts….In the
majority, several axes radiate just beneath the surface
of the soil from the main vertical subterranean axis,
which, except in young plants, is relatively poorly
developed. Sometimes they extend for a distance of
several metres. In some species these axes can reach
a diameter of 10 cm. or more. They are usually very
hard and consist mostly of secondary xylem, the total
amount of which is probably no less than that of a
medium-sized woodland tree growing in the same
general region. These radiating axes are usually
referred to as rhizomes. Their true nature, however,
requires careful investigation since the arboreal
relatives of some suffrutices are said to sucker freely
from their extensive superficial roots.
Here is what Prof. Braam van Wyk had the following
to say in an address at a conference in Nelspruit on
the 13th November 2003 regarding the impact of
timber plantations on grasslands (transcript at www.
geasphere.co.za; accessed 24 April 2008):
Pyrogenic geoxylic suffrutices is a very peculiar growth form that is associated with our grasslands,
and it is very much a type of growth form in Africa. It is not found anywhere else in the world except
perhaps to a limited degree in South America. It is a growth form where you get plants, woody
plants that can be compared to underground trees, and all that you see are these green twigs
which can be compared with a canopy of the tree. And this is probably one plant sitting here, or
maybe even this whole area may be one plant, and it’s the canopy that just sticks out, the tips of the
branches above ground. They burn down every year, but the rest of the tree stays underground.
Why they have adopted this strategy… it is a very interesting challenge to come up with reasons.
Is it fire? We don’t think so. Is some of it frost? Shallow water table? Grazing? There are lots of interesting
things we can say about the reasons why it adopted this strategy and why it only evolved in Africa.
Now these clones, because we call them clones, they are essentially immortal, nothing can kill them.
Grazers can not kill them, fire can not kill them, they are drought resistant. They grow extremely
A geosuff is described by Yolande Steenkamp
and co-authors in PlantLife No. 25 as ‘basically
an underground tree, with a massive, woody,
underground, perennial central axis (often called a
rhizome) and many short-lived (annual) shoots above
ground’. In Burtt Davy’s paper he shows a drawing of
Parinarium capense. (now Parinari capensis. subsp.
capensis) with a huge stem driving down into the
depths. Today, however, it is considered that while
the initiating plant may have had a tap root, in most
instances it dies off and is superseded by an axillary
network of woody roots and stems (rhizomes) which
reach outwards from the point of origin supporting
aerial outgrowths or ramets (individual members of
a clone); see the picture of Eugenia albanensis (Vlei
myrtle). Considering the description by Steenkamp
and co-authors above, we should rather talk of an
extensive, rather than a massive, underground
network of interconnected woody axes. For the
present article, geosuff should be taken to refer to
a species which is woody in itself and mostly with
close relatives that are proper trees. These can be
divided into ‘facultative’ (when forced by outside
pressures) and ‘obligate’ (when compelled by
genetic requirement) geosuffs and here we enter
a rather grey area with the occasional doubt in
deciding what falls into which group. In Pondoland
we have, for example, two species which occur
as trees and also as possible facultative geosuffs,
namely Diospyros scabrida (Coastal bladdernut)
and Ochna natalitia (Natal plane). At present we
assume that the same species may display both life
forms, but future taxonomic investigation, especially
at gene level, might change this. Eugenia capensis
subsp. capensis (Dune myrtle) grows as a shrub or
small tree in dune forests but can occur as a geosuff
along forest fringes, especially when subjected to
frequent grassland fires.
We excavated part of an extensive stand of Eugenia
albanensis (Vlei myrtle), an obligate geosuff,
growing in red sands of the Berea Formation—a
system of ancient coastal dune cordons inland
from our present coastline. After exposing an area
about 3 m long, the growth pattern appeared to
be quite random with narrow (10–20 mm thick)
rhizomes running in all directions about 20 to 50
cm below ground level; we did not see any sign of
a root dropping vertically into the depths. It seems
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slowly, and if you look at the diameter of some of these clones, they must be the oldest inhabitants
of our grasslands. I would say easily more than a thousand years for many of these clones since the
first seed arrived for that particular species. But I would not be surprised if some of them are one
day shown to be perhaps more than 10 000 years old, amongst the oldest plants in the world, much
older than any tree that you are going to see. They are very peculiar plants and we have quite a
number of these species in our grasslands.
probable that the clone exists as a self-regenerating
organism where the rhizomes most likely have a
limited life (perhaps of some years) and are replaced
from time to time. I got the real impression that the
aerial shoots scattered over a large area (about a
hectare) could well prove to be interconnected—if
one could only have X-ray vision. Like the Eugenia
capensis subsp. gueinzii (Coast myrtle) mentioned
below, these clonal colonies must take at least
hundreds of years to establish over such large areas.
Herbaceous clones of non-grassy herbs (‘wild
flowers’) are quite common in fire-prone grassland
and are provided by several families, including
Asteraceae (Helichrysum), Euphorbiaceae
(Acalypha), Fabaceae (Eriosema, Indigofera),
Lamiaceae (Becium) and Rubiaceae (Pentanisia). The
Pondoland Centre endemic, Helichrysum pannosum
(Pondo everlasting), forms large clones several
metres across. A species such as Eriosemopsis
subanisophylla (Mock eriosema), however, seems to
qualify as a true geosuff, the heavy woody rootstock
of this plant and multiple shoots (note that in the
picture of this plant most of the aerial shoots had
been broken off during the excavation due to the
very brittle nature of the species) have a woody
appearance, but the species has no true arborescent
relatives as it is the only member of the genus. It
is nevertheless closely related to other groups of
woody Rubiaceae that include many proper trees.
The potential reasons put forward by the various
authors to explain the evolution of geosuffs from
arborescent ancestors are several and these
include: extreme cold, aridity, water logging,
edaphic constraints, herbivory, fire and soil fertility
(or lack thereof). Burtt Davy points out that a tree
could not invade grassland and then evolve a
suffrutescent habit. The ecotones of forest margins,
however, are dynamic habitats with adventurous
woody plants attempting to push out from the forest
into the grassland. Could these ecotones present
an opportunity for the evolution of geosuffs? A
walk in spring along our forest margins reveals
several otherwise arborescent species putting out
shoots in the ecotone, the endemic Rhynchocalyx
lawsonioides (Mock umdoni) being one of them. The
two species mentioned earlier, Diospyros scabrida
(Coastal bladdernut) and Ochna natalensis (Natal
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plane), occur widely as forest trees but also can be
found as chasmophytes (growing in fire-protected
rock crevices) in and around rock exposures in
the grasslands, often near forests. Under these
conditions, the aerial parts are burnt off regularly,
but I have not seen an indication of reversion to the
arborescent state in places where fire has missed
out a year or two. It would be informative to study
the genetics of the two forms of these species to see
whether they are either facultative geosuffs or, just
possibly, evolving towards the obligate state. The
other possibility would be to take seed of each form
for growing on, but as the transition from one form
to the other may be incomplete, seeds could also
be in a stage of transition and reproduce either way.
The age of plants has always been
a fascination...it is becoming clear
the we have a tencency to seriously
underestimate it.
Looking at the occurrence of geosuffs in the
Pondoland Centre, temperatures are moderate;
dry periods, especially in winter, can occur but
droughts are rare; geosuffs occur on both the
shallower sandstone derived soil of the Msikaba
Formation and on deeper dune sands; herbivory is
a constant; fire is also a constant in our grasslands
(Abbott, PlantLife 35) and the soils are nutrient poor
because of the high rainfall.
Meg Coates Palgrave (PlantLife 18) is convinced
that the success of seedlings in the indigenous
woodlands (‘miombos’) of Zimbabwe is an
infrequent occurrence and suggests that there,
trees normally reproduce vegetatively from
existing rootstocks. This provides an example of the
ancestral ability of woody plants to produce coppice
shoots but still leaves the reasons for adopting the
geosuff growth form (as opposed to a proper tree)
unexplained. In contrast to Meg’s findings in the
Zimbabwe woodlands, our forest species down here
seem to do quite well in setting seed and generating
seedlings although some species certainly flower
irregularly. Even coppicing forest species such as
Dahlgrenodendron natalense (Sandstone quince)
set fertile seed from time to time. Another such tree
is the rare Lydenburgia abbottii (Pondo bushmans
tea) which I have seen with a mass of seedlings
below it.
Compared to our forest regeneration, Pondoland
grasslands appear to depend largely on perennial
species which shoot at ground level or below, socalled
resprouters. The number of herbaceous plant
species which exist as clones is large and as Acocks
(1975) tells us “The Pondoland Plateau Sourveld
is the densest veld in the Republic, so dense that
grasses grow as single shoots rather than as tufts;
at least the tufts are very small.” Thus it seems likely
that seedlings would find it harder to establish
amongst resprouters and tufted species.
The range of selective pressures suggested to
promote the geosuff growth form is quite large,
but the wide range of distribution and conditions
of geosuff occurrence suggests to me that the
pressures of fire and herbivory are indeed
candidates for such a change of behaviour, at least
in the Pondoland Centre. These could well be acting
in concert with some or all of the other factors put
forward. Here, I would suggest the opportunity
offered by forest margin ecotones with grassland
could well be a potential nursery school for the
evolution of geoxylic suffrutices from arborescent
forest forms.
The age of plants has always been a fascination to me
and it is becoming clear that we have had a tendency
to seriously underestimate it. According to a popular
website that, amongst others provides information
on botanical record breakers (waynesword.
palomar.edu accessed 14 April 2008) there is a
shrub in the Mojave Desert called creosote bush,
Larrea tridentata (Zygophyllaceae). The original
stem produces a series of aerial branches but as the
centre of the stem dies off, the remaining portions
continue to grow as a large ring of peripheral shoots;
a growth pattern reminiscent of that in a geosuff,
except that in the case of creosote bush the clone
forms an ever-widening circle surrounding a central
barren area. The oldest of these clones is estimated
to be about 12 000 years old. Another clonal plant,
Lomatia tasmanica (Proteaceae) in Tasmania, may
be one of the oldest plant clones in the world. Known
as the King’s Holly, the species appears to be a
sterile triploid incapable of producing viable seeds
and the existing clones are estimated to be as much
as 43 000 years old! With examples such as these,
we should not be shy to suggest considerable ages
for our geosuffs. There is an extensive clonal colony
of Eugenia capensis subsp. gueinzii (Coast myrtle)
in grassland on the ancient Berea Formation sand
dunes along the Wild Coast which is about 50 x 30
m in extent. No doubt this particular clone must be
many hundreds, if not thousands of years old. This
evidence of long term stability is a very important
consideration when developments are proposed
which can destroy our grasslands. In fact, this
particular colony of Eugenia capesis subsp. gueinzii
(Coast myrtle) grows on dunes earmarked for the
possible mining of heavy minerals. Suggestions
of rehabilitation or revegetation, often mentioned
in environmental assessments, seem rather
presumptuous. It is quite clear that the prefix “re-”
is out of place and all that can happen to grassland
which has been destroyed by development, is the
introduction of plants to provide a covering to the soil
without a hope of restoring the earlier ecosystem.
Anisha Dayaram of Wits University is currently
working on carbon dating some geosuffs in
collaboration with Custodians of Rare and
Endangered Wildflowers (CREW). There is so little
known about the underground parts of plants in
grasslands and I am delighted that Anisha has taken
on this project and I sincerely hope that it will lead
to other investigations into the behaviour of more of
these plants.
Marita Thornhill and Ian Felton (PlantLife 23) feel
that the term “woody grasslands” better describes
the coastal grasslands of Maputaland with their
abundant of geosuffs. Perhaps we should give
thought to changing our terminology for the
Pondoland veld to give recognition to the fact that,
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although individual numbers of grasses exceed all
other kinds of plant in our ‘grasslands’, they are far
the least in species numbers and biomass. Cryptic
Savanna or Dwarf Open Woodland perhaps, but
certainly something which gives better recognition
to the plant assemblage.
References:
1. Abbott, A.T.D. 2006. Where do our beautiful
2.
grasslands come from? PlantLife 35: 3–6.
Burtt Davy, J. 1922. The suffrutescent habit as an adaptation
to environment. Journal of Ecology 10: 211–219.
3. Acocks, J.P.H., 1975. Veld types of South Africa. Botanical
Research Institute, Pretoria.
4. Coates Palgrave, M. 1988. Regeneration of indigenous
woodland in Zimbabwe. PlantLife 18: 30–32.
5. Gunn, M. & Codd, L.E. 1981. Botanical exploration of
southern Africa. B.R.I. A.A.Balkema, Cape Town.
6. Jackson, B. Daydon, 1971. A glossary of botanic terms.
Hafner Publishing, New York.
7. Thornhill, M. & Felton, I. 2000. The underground forests of
Maputaland. PlantLife 23: 9–10.
8. Stearn, W., 1983. Botanical Latin. David & Charles, London.
9. Steenkamp, Y., Kellerman, M.J.S. & Van Wyk, A.E. 2001. Fire,
frost, waterlogged soil or something else: what selected for
the geoxylic suffrutex growth form in Africa? PlantLife 25: 4–6.
10. White, F. 1976. The underground forests of Africa: a
preliminary review. Gardens’ Bulletin, Singapore 29: 55–71.
Virtual Tree Herbarium (ViTH)
Adapted from news items distributed by the University of Johannesburg & Naas Grové
The University of Johannesburg, under the auspices
of Prof Michelle van der Bank and Dr. Oliver Maurin,
is busy developing a Virtual Tree Herbarium (ViTH)
based on the same concept as similar projects for
birds, mammals and other organisms with the Bird
Atlas and Virtual Museum. The general idea is to have
a system available to anyone, to capture tree / shrub
observations from the field. This idea appealed to
the Central Committee of the Dendrological Society
as it has proven to be very successful with projects
such as the Bird Atlas. It is a non-profit initiative
that would allow our members from all branches
to contribute towards the development of more
accurate species distributions maps, and thus
contribute towards science.
The data that would be uploaded by the members
of the Society on the system will only involve
observations and must contain: 1) A Temporary
identification 2)A GPS location and 3) A set of
photographs of the tree, leaves, bark and any other
features such as fruit and flowers (to help confirm
the identification).
A panel of experts then has to screen, evaluate and
verify all submissions at intervals and record those
which can be verified. The verified data would
eventually serve as the basis for an accurate map
and database of tree / shrub species found in all
parts of the country.
The Dendrological Society held a workshop
facilitated by Dr. Oliver Maurin and Professor
Michelle van der Bank on 30 July 2011 at the
University of Johannesburg to discuss the project
and ways to participate. The following members
attended the workshop: Gert Middelberg, Fanie de
Meillon, Izak van der Merwe, Naas Grové, Christoph
Fuhrmann and Walter Barker (Tree Society of South
Africa)
An experimental survey of 33 tree species was
made in Melville Koppies on 15 October 2011 by
the Magalies branch of the Society during an outing
with the botany Masters Student Mr Phillip Rousseau
of the University of Johannesburg, and these were
the first entries to be submitted by the Society on the
ViTH system. Members who wish to contribute to the
project can consult our website for more information
at www.dendro.co.za
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TSATE HERITAGE SITE IN SEKHUKHUNELAND
REUSE VORM VAN XEroPHytA rEtInErVIS – BOBBEjAANSTERT » Foto Naas Grové
The Tsate Heritage Site in Sekhukhuneland
On our way to visit Tsate on 4-6 February 2011,
I tried to imagine how the area would look like
and how could I contribute to a successful outcome.
In all my years of botanizing I always managed to
by-pass the area and consoling myself with the
promise of one day…!!
That day had come, and it couldn’t have been with a
more friendly and knowledgeable group of people
that I was privileged to be with that weekend. I also
came to realize that every-one of the participants
had something unique to add to the total of the
experience.
I fully agree with what has been written by other
members and therefore I will not duplicate
unnecessarily. I will also concentrate more on
the issues raised by Lizanne Nel regarding the
feasibility of a sustainable and profitable project for
the Tsate community. These are only my personal
thoughts which I offer, regardless of the possibility
of “carrying coal to Newcastle”
Basic strategic thoughts
These thoughts are put down randomly as they
come to mind:
• The Sekhukhuneland Centre of Plant Endemism
boasts 58 endemic, 70 near-endemics and 46
threatened plant species. How many did we see
during the 2 days? It will indeed be a challenge
to be able to show the visitor every single one of
them. Why not cultivate them and plant them in
their respective habitats along a special route?
Then one can advertise! Think of a fenced-off,
dedicated Botanical Reserve and include the
NBI and other Departments of the Government
in the planning and execution of such a project.
This idea might spread to the other centers of
plant endemism
• A “Heritage site” is developed and administered,
and its natural and cultural resources protected,
advertised and shown with pride to visitors. It is
not there to be used up for wood or grazing by
the local community.
• Special attention should be given to the
eradication of all alien and weed species.
• People who come for camping are usually
discerning nature lovers. Well situated,
secluded from the local community and
serviced camping sites is a must. High class,
serviced ablution facilities indicate to the visitor
Hans Vahrmeijer
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your attitude towards them. Mediocre facilities
tend to be vandalized very quickly.
• The Heritage site is a cultural- historic site for
the Bapedi people, and it should be the Bapedi
who must be the main “marketing focus”. This
means that the site must be enriched in such
a way that the visitor can experience a full or
‘complete’ Pedi cultural experience. A good
development avenue will be the incorporation
of this cultural experience (visit to Tsate) in
the formal curriculum of at least the schools
serving the Bapedi people.
• One of the most underrated attractions is
certainly the “Musical Rocks”. I don’t know their
history, or even if the Bapedi used them. Judging
by the wear on the rocks they must have played
a central role in some cultural activity for many,
many years. An in-depth study should be done
on them by professional scientists and the rocks
should enjoy special protection. If some of the
older Pedi still know how to play them, or some
can teach themselves to do it, it will be a unique
opportunity to produce “ancient” music such as
can be heard nowhere else in the world. This
can become a major draw-card for the project.
• The Heritage site can only be sustainable when
it serves the purpose for which it has been
established and when it is also advantageous to
the community in which it is located.
• With the government’s interest, professional
knowledge of the developers, interest of
various professional bodies and organizations
becoming aware of Tsate, a lot of knowledge,
interest, advice, help, public interest and even
money tend to gravitate towards the project.
These formal and informal resources should be
used to the maximum to achieve the goals.
• In the present times, money-driven, successful
profit centers ‘rules the roost’ and determines
the success or failure of a project like Tsate.
This makes it imperative for Tsate to plan for
such projects.
Possible projects for Tsate
1. Establishing a nursery to legally sell indigenous
plants grown from mother stock in the Endemic
Plant Centre. I am sure Searsia batophylla will be
a horticultural success. I am sure Tsate will be
able to obtain permits to sell rare and endangered
species propagated in their nursery.
2. Planting Dovyalis species like the Kei-apple
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TSATE HERITAGE SITE IN SEKHUKHUNELAND
with its prolific fruits in an orchard, a huge
source of vitamin-rich fruit juice or jam for local
and national markets.
3. Planting medicinal plants in the veld to be
harvested and sold in muthi-markets
4. With the help of the CSIR (ECD) in Pretoria it is
possible to design a project for the production
of aromatic oils suitable for the Tsate area.
5. Planting of a woodlot for the community. The
mines in the area and those at Burgersfort
will most likely have a Trust fund for the
development of the communities (Social
responsibility fund) which can be contacted
for participation in the projects.
6. Why not design an overall network in the
country for all the different cultures (Maybe only
the main ones) where especially the overseas
visitors can experience cultural contact.
Cultural Tourism is on the rise as experienced
in Soweto, Zululand and other areas. These
cultural centers or Heritage sites can liaise and
network to help and ‘cross-pollinate’ each other.
7. Contact the historical associations, wargrave
commissions, cultural attaché’s of
the UK and Swaziland to raise interest in
building a memorial for their own people who
participated in the 1879 war.
8. Design a big hall and enough ablution facilities
to accommodate big gatherings of the Bapedi,
be it of political, cultural, social or whatever
nature. The facilities can be leased to pay for the
maintenance. The bottom line is—Make Tsate a
cultural centre for the Bapedi in practice.
I trust that these loose ideas stimulate further
thoughts that will help put Tsate on the tourist maps.
My contribution to the tree and plant lists of the
Tsate area is depicted in the tables below:
Medicinal plants
Acacia caffra
Acacia karroo
Acacia mellifera subsp. detinens
Acacia nilotica subsp. kraussiana
Acokanthera oppositifolia
Acridocarpus natalitius
Albizia anthelmintica
Aloe marlothii
Balanites maughamii
Bauhinia tomentosa
Berchemia zeyheri
Berchenia zeyheri
Bolusanthus speciosus
Boscia foetida subsp. rehmanniana
Brachylaena ilicifolia
Buddleja saligna
Calodendrum capense
Carissa bispinosa subsp. bispinosa
Catha edulis
Catharanthus roseus
Celtis africana
Chaetachme aristata
Cissampelos mucronata
Clematis brechiata
Clerodendron ternatum
Clerodendrum glabrum
Combretum apiculatum
Combretum hereroense
Combretum imberbe
Combretum molle
Combretum zeyheri
Commelina benghalense
Croton gratissimus var. gratissimus
Cussonia paniculata
Cyphostemma natalitium
Datura stramonium
Dichrostachys cinerea subsp. africana
Diospyros lycioides subsp. lycioides
Dombeya rotundifolia
Dovyalis caffra
Ehretia amoena
Ehretia rigida
Elaeodendron transvaalense
Elephantorrhiza burkei
Euclea crispa
Euphorbia cooperi
Euphorbia ingens
Euphorbia tirucalli
Evolvulus alsnoides
Flueggea virosa
Gomphocarpus fruticosus
Grewia flavescens
Gymnosporia buxifolia
Helinus integrifolius
Heliotropium ciliatum
Heteromorpha arborescens var. abyssinica
Hippobromus pauciflorus
Lantana rugosa
Lippia javanica
Maerua angolensis
Mimusops zeyheri
Monsonia angustifolia
Mundulea sericea
Myrothamnus flabellifolius
obetia tenax
olea europaea subsp. africana
Pappea capensis
Pellaea calomelanos
Peltophorum africanum
Phyllanthus parvulus
Polygala virgata var. decora
Pouzolzia mixta
Psiadia punctulata
Pterocelastrus echinatus
rhoicissus tridentata subsp. cuneifolia
Sarcostemma viminale
Schotia brachypetala
Sclerocarya birrea subsp. caffra
Sideroxylon inerme
Solanum lichtensteinii
Spirostachys africana
Steganotaenia araliacea
Strophanthus speciosus
tarchonanthus camphoratus
tecoma capense
trimeria grandiflora
turraea obtusifolia
Vangueria infausta
Vangueria infausta
Vitex obovata
Withania somnifera
Xerophyta retinervis
Ximenia americana var. microphylla
Ximenia caffra
Zanthoxylum capense
Ziziphus mucronata
Edible plants
Acacia karroo
Asparagus buchananii
Bauhinia tomentosa
Berchemia zeyheri
Boscia foetida
Carissa bispinosa
Cleome gynandra
TSATE HERITAGE SITE IN SEKHUKHUNELAND
Corchorus tridens
Diospyros lycioides
Dovyalis caffra
Ehretia rigida
Elaeodendron transvaalense
Euclea crispa
Ficus abutilifolia
Ficus glumosa
Ficus tettensis
Grewia discolor
Grewia flava
Grewia flavescens
Mimusops zeyheri
Myrothamnus flabellifolius
olea capensis subsp. enervis
olea europaea subsp. africana
Pappea capensis
Schotia brachypetala
Sclerocarya birrea
Searsia lancea
Searsia transvaalensis
Vangueria infausta
Vangueria madagascariensis
Vigna unguiculata
Ximenia americana
Ximenia caffra
Ziziphus mucronata
Poisonous plants
Acokanthera oppositifolia
Argemone ochroleuca
Asclepias fruticosa
Datura stramonium
Euphorbia cooperi
Euphorbia ingens
Euphorbia tirucalli
Ficus salicifolia
Gnidia polycephala
Kalanchoe thyrsiflora
Lantana camara
Lippia javanica
Mundulea sericea
nicotiana glauca
obetia tenax
Pavetta lanceolata
Sarcostemma viminale
Senecio retrorsus
Solanum lichtensteinii
Spirostachys africana
Strophanthus speciosus
tribulus terrestris
Xanthium spinosum
Xanthium strumarium
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VERTROETEL jY UITHEEMSE INDRINGERPLANTE IN jOU TUIN?
Vertroetel jy uitheemse indringerplante in jou tuin?
Rustenburg lê aan die voet van die Magaliesberg
en die grootste gedeelte van die stad lê binnein
of is aangrensend aan die oorgangsgebied van
die voorgestelde Magaliesberg-biosfeer.
Biosfeer reservate of natuurgebiede is beskermde
gebiede wat van internasionale bewaringsbelang is.
Dit is unieke kategorieë van beskermde gebiede en
dit behels ’n kombinasie van beide natuurbewaring
sowel as volhoubare benutting van natuurlike
hulpbronne. Die hele Magaliesberg-gebied vanaf
Cullinan in die ooste tot Pilanesberg
in die weste is onder leiding van die
United Nations Educational, Scientific
and Cultural Organisation (UNESCO),
in die finale stadium om as ’n biosfeer
geproklameer te word. Dit sal slegs
die sewende geproklameerde biosfeer in Suid-
Afrika wees. Die ander gebiede wat ook as biosfere
verklaar is, is die Kogelberg in die Wes-Kaap, die
Weskus, die Waterberg, die Kruger Nasionale
Park wat die Blyderivierpoort insluit, die Kaapse
Wynland en Vhembe in die noorde van die Limpopo
provinsie, wat Mapungubwe insluit.
‘n Biosfeer is dus die biologiese komponent wat
die totale ‘pakket’ van alle lewende organismes op
aarde of dan in ’n spesifieke gebied of area, asook
die dooie materiaal wat deur die lewe tot stand
kom, insluit. Ekologies gesproke is die biosfeer
dus ‘n ‘globale ekosisteeem’ en dit sluit dus alle
vorme van biodiversitiet op die aarde of dan in die
verklaarde gebied in. As gevolg van die langtermyn
interaksie oor biljoene jare tussen die biosfeer en
ander stelsels (atmosfeer, litosfeer, hidrosfeer, ens.)
op die aarde is daar bykans nie ’n deel van die
aarde se oppervlakte wat nie ingrypend aangeraak
word en verander is deur lewende organismes nie.
Die aarde is immers ’n lewende planeet en al die
organismes het aangehou om die aarde tot voordeel
van hulself te verander. Die biosfeer kan dus ook
die strook van lewe op aarde genoem word.
Biodiversiteit is een van die aarde se grootste bates.
Lewe op aarde voorsien aan die mens voedsel, suiwer
die lug wat ons inasem, filter die water wat ons drink
en dit vorm die basis van ‘n oneindige hoeveelheid
medisyne. Dit sluit ook indirekte voordele in soos
bekamping van erosie, regulering van die klimaat en
watervlakke. Verder het dit ook ’n kulturele waarde
wat bestaan uit natuurlike landskappe wat manifesteer
Naas Grové
Biodiversiteit is
een van die aarde se
grootste bates.
in die gepaardgaande ontspanningsgeriewe en
-aktiwiteite wat dit aan mense bied.
Ongelukkig is hierdie natuurlike bronne onder
geweldige druk. Van die grootste bedreigings vir
die vernietiging van biodiversiteit sluit ongetwyfeld
indringer plantspesies, klimaatverandering,
besoedeling en habitat vernietiging of -verandering
in. Dit is dan ook nie snaaks nie dat die rol van die
mens in al voorgenoemde duidelik sigbaar is. Indien
die mens dus nie baie gou planne in plek sit om hierdie
drywers van biodiversiteit vernietiging suksesvol aan
te spreek nie, sal ons toeskouers
wees van ons vernietigende hande
arbeid. Die verlies aan biodiversiteit
het ‘n geweldige negatiewe
uitwerking op die integriteit van
alle ekossisteme (die omgewing of
die natuur) en gepaardgaande daarmee sal enige
poging tot volhoubare benutting van die natuurlike
hulbronne, in watter vorm ookal, futiel wees. Wanneer
ons biodiversiteit vernietig, verloor ons unieke gene,
spesies en ekosisteme asook alles wat die mens tot sy
voordeel kan benut of gebruik.
Een van die grootste probleme vir die huidige stand
van sake is indringerplante en daar is waarskynlik
nie ‘n huishouding in Suid-Afrika wat onskuld kan
pleit nie. Wanneer na uitheemse indringerplante
verwys word is dit nie dieselfde konteks as die
fiksie rolprente se storie lyne oor vreemde vlieënde
voorwerpe nie. Inteendeel dit verwys na biologiese
spesies soos plante, fungi, bakterieë en diere wat
buite hul natuurlike habitat verspreiding ’n ernstige
bedreiging inhou vir die biodiversiteit van die
‘nuwe’ gebied waar binne hulle hulself tuismaak.
’n Spesie kan uitheems wees, sonder dat dit ’n
indringer is. Dink maar aan al die graan, mielies,
sonneblom, aartappels, ens., wat almal hul
oorsprong elders in die wêreld het en tog voedsel
aan miljoene mense dwarsoor die wêreld verskaf.
Dus is alle uitheemse spesies nie ongewens nie.
Om indringer status te verdien moet die spesie
aangeplant word, dit moet oorleef en tot so ’n mate
floreer dat dit die natuurlike inheemse spesies
heeltemal oorheers of verdring. ’n Goeie voorbeeld
hiervan is die uitheemse Australiese Acacia spesies
wat oral op die Hoëveld die natuurlike grasveldekosisteme
binne gedring en totaal versteur het. Al
die indringer plant spesies het dus ’n paar dinge in
gemeen:
• Hulle groei en versprei baie vinnig.
• Hulle het almal die vermoë om hul saad oor ’n
wye gebied te versprei.
• Die plante is fisiologies goed aangepas by
die nuwe klimaat kondisies en hulle kan
so in verskillende grondtipes en in uiterste
klimaatomstandighede floreer.
Per definisie is die uitheemse plante nie slegte
spesies nie, hulle het net ’n potensiële vernietigende
uitwerking op die biodiversitiet van die natuurlike
omgewing, indien dit nie behoorlik beheer word nie.
Suid-Afrika huisves tans meer as 25 000 uitheemse
plant spesies.
Dit kos die belastingbetaler jaarliks
biljoene rande om uitheemse
indringerplante te bestry.
Daar is in totaal 220 uitheemse plantspesies
ingevolge die Die WET OP DIE BEWARING VAN
LANDBOUHULPBRONNE, 1983 (WET No. 43 VAN
1983 soos gewysig in MAART 2001) as ongewens in
SWAARDVARING » nephrolepis ezaltata
VERTROETEL jY UITHEEMSE INDRINGERPLANTE IN jOU TUIN?
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drie verskillende kategorieë geklassifiseer. Hierdie
plante het reeds ’n gebied van 15 miljoen hektaar
(so groot soos KwaZulu-Natal) binnegedring. Daar is
beswaarlik nie ’n bergkompleks, bosveld-, savanna-
of grasveldbiome in Suid-Afrika wat nie in ‘n mindere
of meerdere mate deur een of meer indringerplante
bedreig word nie. Dit kos die belastingbetaler jaarlks
biljoene rande om die plante te bestry.
Baie van hierdie plante word tans binne in huise,
in tuine en in visdamme aangehou en vertroetel.
Van die algemene indringers wat ek oral in tuine
opmerk is swaardvaring (Nephrolepis exaltata –
uitgesonder steriele kultivars), meeste van die privet
bome en struike (Lingustrum spp.), maandblomme
(Ipomoea alba, I. lndicaen I. purpurea), mak sering
(Melia azedarach), selonsroos (Nerium oleander –
behalwe gekultiveerde plante met dubbel blomme),
skubliesroos (Litsea glutinosa ), waterslaai (Pistia
stratiotes ) en water hiasinte (Eichhornia crassipes).
Die lys is eenvoudig te lank om by te hou.
Van ons sypaadjies en winkelsentrum parkeer-areas
is besoedel met indringerplante soos die wynboom
of belhambra (Phytolacca dioica), Brasiliaanse
peperboom (Schinus terebinthifolius), vlinder-orgideë
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VERTROETEL jY UITHEEMSE INDRINGERPLANTE IN jOU TUIN?
(Bauhinia purpurea en B. variegata), Kanferboom
(Cinnamomum camphora), jakaranda (Jacaranda
mimosifolia), treur-wilger (Salix babylonica,
wat nie verwar moet word met die inheemse
wilgers nie), moerbei (Morus alba - uitgesonder
die kultivar Pendula wat as wortelstok gebruik
word), wasboom (Rhus succedanea), Tipu-boom
SELONROOS » nerium oleander
(Tipuana tipu), sisal (Agave sisalana), Australiese
silwer-eik (Grevillea robusta), Australiese kasuur
(Pittosporum undulatum), Spaanse-riet (Arundo
donax), pampasgras (Cortaderia selloana –
uitgesonder steriele kultivars), geel-kassia (Senna
didymobotrya), lukwart (Eriobotrya japonica),
geelklokkies (Tecoma stans), koejawel (Psidium
guajava) en alle saaddraende vorms van die lantana
spesies (Lantana camara).
Ongeveer 10% van Suid-Afrika se jaarlikse
watervoorraad word deur indringer plante
opgebruik. Indringer plante het geen of weinig
natuurlike vyande in Suid-Afrika, met die gevolg
dat hulle die inheemse plante verdring en later
vernietig. Groot stande uitheemse plante
veroorsaak erosie en dit skep ‘n brandgevaar. In
’n gebied wat as biosfeer verklaar is, is die vereiste
dus die bewaring van die diversiteit van plante, diere
en mikro-organismes wat almal saam die lewende
biosfeer uitmaak. Vanselfsprekend beteken dit dat
almal wat van Cullinan tot Pilanesberg onlosmaaklik
aan die Magaliesberg verbind is en sekere
verantwoordelikhede het teenoor die bewaring van
hierdie voorgestelde biosfeer.
Dit het derhalwe nodig geword dat iets drasties
gedoen word om die verspreiding en aanplanting
van die plante in te kort of selfs op te skort.
Die gevaar van indringerplante lê daarin, dat dit
digte stande vorm wat die natuurlike plantegroei
verdring soos gesien kan word in die geval van
Lantana camara en Tecoma stans wat oral in die
gebied ter sprake voorkom. Omdat die plante geen
of min natuurlike vyande het en onder dié gunstige
omstandighede groot hoeveelhede saad per jaar
produseer kan die verspreiding daarvan eenvoudig
nie maklik beheer word nie.
Daar is verskeie maniere om die probleem aan te
spreek en ’n goeie wegspring plek is sekerlik om
te begin met ’n bewusmaking en inligtingsveldtog.
Sodra ’n mens weet waarna om te kyk en meer van
die indringer plante weet kan daar daadwerklik tot
aksie oorgegaan word. Uiteindelik kan daar dan
met die kennis tot ons beskikking tot een van die
volgende aksies oorgegaan word:
• Voorkoming is die eerste lyn van verdediging
teen uitheemse indringer plante. Op die
langduur is dit ook die goedkoopste en mees
praktiese metode. Dit behels kennis van die
wet en watter van die uitheemse spesies as
ongewenste indringerplante geproklameer
is. Dit behels ook metodes hoe om hoë
risiko gebiede waar die plante voorkom te
identifiseer en maatreëls in plek te sit vir die
beheer daarvan. Sonder enige moeite kan
elke huishouding, deur nie van die ongewenste
plante aan te hou nie, klaar help in die proses
van voorkoming.
• Uitroei van die plante uit ’n bepaalde gebied.
Hoe langer ’n uitheemse indringer alleen
gelaat word, hoe moeiliker en duurder word dit
om dit te beheer. Deur die plante te verwyder
is dikwels goed genoeg vir die natuurlike
plantspesies om hulself weer te hervestig.
• Beheer die verspreiding van die plante met
doelgerigte metodes om te verhoed dat die
plante buite ’n bepaalde geografiese gebied
versprei. Die doel is om die plant populasie
te beheer en te verminder sodat dit nie hande
uitruk nie. Sodra die populasie onder ’n seker
groei kom sal die natuurlike plante genoeg
voorsprong hê om hulself weer te hervestig en
so die uitheemse plante natuurlik verdryf.
Navorsing dui daarop dat daar mikroskopies klein
bakterieë bestaan wat doeltreffender as bome is in
die vervaardiging van suikers. Wetenskaplikes beoog
om die klein ‘moderne‘ bakterieë in te span om te help
voorsien aan die toenemende wêreldvraag na voedsel.
In die volgende paragrawe word meer agtergrond
verskaf oor waarom die fotosintese van ‘moderne’
sianobakterieë beter as dié van landplante soos bome
is, watter soorte fotosintese in landplante voorkom en
hoe die mens die fotosinteseproses kunsmatig kan
inspan vir verhoogde voedselproduksie.
Hoe bome se produktiwiteit agter geraak het
Volgens die evolusieteorie bestaan sianobakterieë
wat kan fotosinteer al drie miljard (3000 miljoen) jaar
op aarde. Hierdie primitiewe bakterieë het fotosintese
uitgevoer in ’n omgewing wat baie anders is as dit wat
ons vandag ken. Die atmosfeer het toentertyd ’n veel
hoër konsentrasie koolsuurgas bevat as die 0.039%
van die huidige atmosfeer, en die konsentrasie
suurstof (O 2 ) was destyds veel laer as die huidige
21%. Bowendien het die bakterieë in water (oseane,
mere) gelewe. Die fotosinteseproses wat deur hulle
gebruik is, was vir daardie omstandighede geskik.
Uit die beskikbare gegewens lei wetenskaplikes af dat
sekere eenvoudige organismes (protista) ’n miljard
jaar gelede van hierdie primitiewe sianobakterieë in
hulle selle opgeneem en ‘gevange’ gehou het. Die
sianobakterieë is ‘beskerm’ binne die selle waardeur
hulle opgeneem is, en het nog steeds deur fotosintese
suikers geproduseer waardeur die selkompleks
gebaat het. ’n Simbiotiese verhouding het so ontstaan
en die ‘sianobakterieë’ het binne selle ontwikkel tot
dit wat ons vandag as chloroplaste ken (Figuur 1).
Alhoewel die fotosinteseproses van die chloroplaste in
selle basies vergelykbaar is met die fotosinteseproses
van die vrylewende primitiewe sianobakterieë van
destyds, is hulle totaal afhanklik van die selle waarin
hulle voorkom. So byvoorbeeld, bevat chloroplaste
nie al die nodige gene vir die fotosinteseproses nie,
maar kom sommige van die noodsaaklike gene in
die nukleusse van die selle voor. Die funksionering
van chloroplaste word dus deur die selle waarin
hulle voorkom, beheer. Alle landplante het uit die
aanvanklike simbiotiese verhouding ontwikkel met
die gevolg dat die basiese fotosinteseproses wat hulle
gebruik om voedsel (soos suikers) te vervaardig, ’n
miljard jaar gelede al ontwikkel is!
Klink hierdie evolusionêre siening dat chloroplaste
eers vryswemmende sianobakterieë was,
Is bome swak kosmakers?
fanie de Meillon
IS BOME SWAK KOSMAKERS?
vergesog? Die argumente wat hierdie siening
staaf, kan op Wikipedia onder “Endosymbiotic
theory” gelees word.
FIG 1 Selle van die mosplant Plagiomnium affine
waarin die groen chloroplaste duidelik gesien
kan word. Wikipedia: Chloroplast.
Die probleem met die fotosinteseproses van
bome
Natuurliefhebbers, en veral boomliefhebbers, is
geneig om die Natuur as volmaak te beskou. Tog blyk
dit dat daar uit ’n menslike oogpunt ’n ‘probleem’ is
met die heel eerste reaksie van die fotosinteseproses
in die chloroplaste van die selle van bome en alle
ander groen plante.
RuBP CO 2 O 2
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FIG 2 ’n Skematiese voorstelling wat die
kompetisie tussen CO 2 en O 2 vir bindplek op die
ensiem Rubisco aandui.
In die heel eerste reaksie verbind
koolsuurgasmolekule (CO 2 ) met molekule van
ribulose-1,5-bisfosfaat (RuBP: ’n ribose-suiker met
twee fosfaatgroepe aan). Die reaksie is slegs moontlik
deur die bemiddeling van ’n ensiem waarvan die
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IS BOME SWAK KOSMAKERS?
naam as Rubisco afgekort is (Figuur 2). Rubisco werk
heel gaaf om die reaksie te kataliseer mits die CO 2 -
konsentrasie hoog is. Drie miljard jaar gelede, toe die
atmosferiese CO 2 -konsentrasie hoog was, sou Rubisco
dus goed in primitiewe sianobakterieë gefunksioneer
het. Die Rubisco ensiem vaar egter nie so goed
onder huidige atmosferiese toestande van ’n lae CO 2 -
en hoë O 2 -konsentrasie nie want die O 2 -molekule
kompeteer nou met die CO 2 -molekule vir bindplek
aan die ensiemmolekule. Weens die kompetisie
tussen CO 2 - en O 2 -molekule bind daar dus minder
CO 2 -molekule per sekonde aan die Rubisco-ensiem.
Boonop veroorsaak die binding van die O 2 -molekule
aan Rubisco dat afwykende reaksies (fotorespirasie)
plaasvind wat fotosintese minder doeltreffend maak.
Kan bome se fotosintese deur mutasies
verbeter word?
Veronderstel dat daar ’n ‘gunstige’ mutasie in die
chloroplaste van ’n blaar sou plaasvind waardeur ’n
beter Rubisco ensiem sou ontstaan. So ’n gunstige
mutasie kan ongelukkig nie na ander volwasse
blaarselle of na ander blare versprei nie want
chloroplaste migreer nie tussen selle nie. As die
blaar met die gunstige mutasie dus verouder en
afval, sal die mutasie verlore gaan. Om verskeie
redes is die kanse maar klein dat ’n gunstige
mutasie in enkele chloroplaste van ’n plant na ’n
nageslag oorgedra kan word.
Wat die vrylewende sianobakterieë in die oseane
en mere betref, is die situasie anders. Mutasies kan
makliker plaasvind, en ’n sianobakteriesel met ’n
gunstige mutasie kan geredelik aanteel en in groot
hoeveelhede voorkom. Dit is skynbaar wat 0.4 miljard
(400 miljoen) jaar gelede gebeur het. Op daardie
stadium het die CO 2 -konsentrasie van die atmosfeer
beduidend begin daal en ‘moderne’ sianobakterieë
het toe ontstaan wat daarby kon aanpas. Die
aanpassing het behels dat mikrokompartemente
in die sianobakterieë ontstaan het en daarby het
membraan-‘pompe’ ontwikkel wat CO 2 aktief in die
mikrokompartemente inpomp. Sodoende word ’n
hoë CO 2 -konsentrasie in die mikrokompartemente
verkry en kon die Rubisco-ensiem van die ‘moderne’
vrylewende sianobakterieë effektief funksioneer.
Kan landplante dan nie ook koolsuurgas
konsentreer nie?
Ja inderdaad beskik sekere landplante beskik wel
oor meganismes om CO 2 te konsentreer maar hulle
maak nie van CO 2 -‘pompe’ en mikrokompartemente
gebruik nie. Hulle is egter in die minderheid en
verreweg die meeste soorte plante maak nog van die
‘primitiewe’ proses (C 3 -fotosintese) gebruik sonder
dat die CO 2 vooraf gekonsentreer word. Die gewone
fotosintese word C 3 -fotosintese genoem omdat die
eerste stabiele fotosinteseproduk wat ontstaan, se
molekule drie koolstofatome lank is.
Sekere ekonomies belangrike landplante (suikerriet,
mielies, sorghum) beskik oor ‘n fotosinteseproses
(C 4 -fotosintese) waardeur CO 2 gekonsentreer word
en die soort fotosintese is eers in die sestigerjare
van die vorige eeu ontdek. Die blare van C 4 -plante
is anatomies aangepas om die konsentrering van
CO 2 moontlik te maak. Eerstens word die CO 2
doeltreffend in gewone blaarselle gebind deur
’n karboksilase-ensiem en dus nie deur Rubisco
nie. Die appelsuur of ander C 4 -verbinding wat so
gevorm word, word na dikwandige skedeselle
wat om die blaar-are gerangskik is, vervoer. Daar
word die C 4 -verbinding ontbind en word die CO 2
weer vrygestel. Die CO 2 kan nie maklik uit hierdie
dikwandige selle ontsnap nie en kom dus in hoë
konsentrasies daarin voor, waar dit dan sonder die
belemmering van O 2 aan die Rubisco-ensiem kan
bind en die normale ‘primitiewe’ C 3 -fotosintese vind
dan in die chloroplaste van die skedeselle plaas.
Die enigste boomspesie wat tot dusver ontdek is
wat tot C 4 -fotosintese in staat is, is ’n Euphorbia.
Die derde soort fotosintese wat deur sekere
landplante uitgevoer word en waardeur CO 2 vooraf
gekonsentreer word, word CAM-fotosintese genoem,
kom in sekere vetplante voor en stel hulle in staat om
in dor gebiede te groei. Die plante se huidmondjies
is, in teenstelling met alle ander plante, bedags toe en
snags oop. Die CO 2 kom die plante dus snags binne,
word deur ’n karboksilase-ensiem in gewone selle
gebind en die suur wat so ontstaan, hoop gedurende
die nag in die selle op. Soggens, wanneer die son
opkom, gaan die huidmondjies toe en die suur ontbind
om CO 2 vry te stel. Die CO 2 kan nou nie ontsnap nie
en die toe huidmondjies verhoed ook dat die plante
bedags water verloor. Omdat die CO 2 -konsentrasie
binne die plant soggens hoog is wanneer die son skyn,
kan dit aan die Rubisco bind sonder belemmering van
O 2 en die ‘primitiewe’ C 3 - fotosintese vind plaas in die
chloroplaste van die blaarselle. Vetplante wat CAMfotosintese
gebruik, groei baie stadiger as ander
plante. Die epifitiese boom Clusia rosea is uitsonderlik
deurdat dit CAM-fotosintese bedryf.
Planne om die fotosinteseproses te manipuleer
Die jongste planne behels om die CO 2 -‘pompe’
(spesiale proteïene) van ‘moderne’ sianobakterieë
in die chloroplaste van plantselle in te bou. Twee
van die pompe word deur ’n enkele geen gekodeer
wat die plan dus heel uitvoerbaar behoort te maak
met die hulp van moderne geentegnologie. Met die
verhoogde CO 2 in die chloroplaste behoort Rubisco
beter te funksioneer en sal plantproduksie sdoende
opgestoot kan word.
’n Meer ambisieuse plan is om die gene vir
mikrokompartemente wat CO 2 kan konsentreer
(karboksisome) uit sianobakterieë te kry en
na plantselle oor te dra. Karboksisome bestaan
hoofsaaklik uit membrane wat sodanig uit proteïene
opgebou is dat CO 2 moeilik daaruit kan ontsnap.
Daarby bevat hulle pompe wat CO 2 aktief na binnedra.
Die kuns is dus om die hele stel van nege gene wat
vir karboksisome en meegaande ensieme kodeer,
susksesvol na plantselle oor te dra sodat dit met
die werking van die chloroplaste kan integreer. Die
navorser Martin Warren en sy span het al daarin
geslaag om kunsmatige mikrosome in die bakterie
Escherichia coli in te bou en hulle dink dis haalbaar om
’n kunsmatige karboksisoom saam te stel.
Nog meer ambisieus, en aansienlik moeiliker,
is die plan om die hele battery gene wat vir C 4 -
fotosintese benodig word, na gewone C 3 -plante oor
te dra. Baie gene is hierby betrokke: gene vir sowel
spesiale ensieme as vir anatomiese veranderings om
dikwandige skedeselle om die vaatbondels te verkry.
Navorsers het al daarin geslaag om die gene vir
enkele van die spesiale C 4 -ensieme na rysplante oor
te dra maar dit het nog geen toename in rysproduksie
tot gevolg gehad nie.
Die stikstof probleem
Plante benodig groot hoeveelhede stikstof vir die
fotosintese-masjinerie, en veral vir die sintese van
die relatief groot hoeveelhede Rubisco-ensiem wat
benodig word. Beperkte hoeveelhede stikstof in
die vorm van nitrate, ammonium en urea kom egter
in grond voor. Dit het aanleiding gegee tot nog
’n opwindende droom: om plante deur genetiese
manipulering so te verander dat hulle die stikstofgas
in die atmosfeer kan benut. Stikstof (N 2 ) is chemies ’n
baie onaktiewe gas maar wat in groot hoeveelhede
voorkom – amper 78% van die atmosfeer.
Omdat stikstof so inert is, is dit moeilik om dit na
ammonium of nitrate om te skakel. Wat so verstommend
is, is dat geen plante dit nog op hulle eie kon regkry
nie, behalwe in assosiasie met heel klein onsigbare
IS BOME SWAK KOSMAKERS?
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mikroörganismes. Mikroskopies klein bakterieë
(Rhizobium, Azotobacter, en ander) doen wat geen
reuseboom nog op sy eie kon regkry nie.
Peulplante, soos doringbome, kan in simbiose met
Rhizobium-bakterieë wel stikstof bind. Die bakterieë
word in knoppies op die wortels van peulplante
aangehou maar die hele proses om die bakterieë
in die wortelknoppies te huisves en in assosiasie
met hulle stikstof te bind, is so ingewikkeld dat
wetenskaplikes liewers wil probeer om die masjinerie
vir N-binding uit die bakterieë te verkry en dit na die
chloroplaste van blaarselle oor te dra. Die voordeel
daarvan is dat chloroplaste alreeds verskeie van
die ensieme bevat wat vir N-binding nodig is, sodat
‘slegs’ agt gene i.p.v. 20 gene van bakterieë na
chloroplaste oorgedra hoef te word. Die nadeel is dat
die binnekant van chloroplaste suurstof bevat, maar
dat die hoofspeler in N-binding, naamlik die ensiem
nitrogenase, slegs in ’n suurstof-vrye omgewing
aktief is. Een oplossing vir die probleem sal wees om
die bakterie Azotobacter se truuk uit te haal, naamlik
om N-binding snags te doen wanneer fotosintese
nie plaasvind nie. ’n Ander moontlike oplossing
sou wees om die gene vir N-binding in wortels te
laat funksioneer waar fotosintetiese suurstof nie ’n
probleem behoort te wees nie.
Daar is wetenskaplikes by universiteite, institute en
by private firmas wat hard daaraan werk om al die
drome te realiseer. Die vordering op tegnologiese
gebied is so snel dat dit waarskynlik slegs enkele jare
sal wees voordat voedselproduksie op bogenoemde
innoverende wyses drasties verhoog sal word.
En ons geliefde bome – hoe lank voordat hulle in
wetenskaplikes se visier kom? Wel, eksperimentering
word gewoonlik eers met vinnig-groeiende plante soos
eenjariges en met krities-belangrike voedselgewasse
soos rys uitgevoer voordat vrugtebome aan die
beurt sal kom. Intussen bly die mensdom steeds
afhanklik van die ‘primitiewe’ en ‘ondoeltreffende’
fotosinteseproses waardeur bome en alle ander groen
plante op aarde groei en gedy en tot voordeel van die
mensdom produseer.
Verwysings:
1. Holmes, Bob. 2011. Billion-year upgrade. New Scientist,
Feb., pp 42-45.
2. Wikipedia: Chloroplast.
3. Wikipedia: Endosymbiotic theory.
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NEW TREE SPECIES DISCOVERED IN KWAZULU-NATAL
New tree species discovered in KwaZulu-Natal!
A newly discovered tree species found only in
KwaZulu-Natal was recently published in the South
African Journal of Botany. The tree is a species of
Combretum, popularly known as bushwillows, many
of which are common and conspicuous features of
the African bushveld.
The new tree has been named Combretum stylesii,
and is a rare species known so far only from a
rugged, ten kilometre stretch of the Tugela River,
within the Maphumulo District Municipality to the
north of Durban. It appears to have been hidden by
its inaccessible habitat, although this is now being
threatened by road development and rural sprawl.
The tree is named after David Styles, a member
of BotSoc KZN Coastal Branch who has collected
several thousand plant specimens in the province
over the past decade, in the process discovering
a number of other, smaller plant species. David is
editor of the journal published jointly by BotSoc KZN
Coastal Branch and the Durban Botanic Gardens
Trust, PlantLife, and he is founder and administrator
of the Yahoo! discussion group, Plant-chat.
David first found the tree in 2004, but although he
realized that it was an unknown species, both fruits
and flowers were needed in order to complete its
description. It took four years for this to occur. As
David explains: “the locality is remote and flowering
is brief and erratic. Many visits were made to the
area. In some years no flowers were found or
flowering was just missed.”
Eventually complete material was collected and
sent to Olivier Maurin, a Ph.D. student studying
the family at the University of Johannesburg, and
Professor A.E. (Braam) van Wyk, the renowned plant
taxonomist based at the University of Pretoria.
In addition to more obvious distinguishing features,
bushwillow species can be distinguished from each
other by tiny scales on the leaves that are as unique
as a human fingerprint. The scales of Combretum
stylesii were also studied under a microscope and
Marilyn Bodasing
LEAVES & FRUIT of the » Combretum stylesii
its DNA was analyzed, proving its distinctness from
other known species.
The tree grows both on its own and as a vigorous
strangler, climbing up and over other trees. The
vegetation in which it occurs is classified as Eastern
Valley Bushveld and the area is arid and hot with
temperatures often reaching over 40 degrees
centigrade in the summer.
According to David, “It is possible that this new
Combretum occurs at other localities in this area, as
vegetation along this part of the Tugela River is not
well known.” He also believes that more exploration
of this interesting area could result in other new
discoveries being made.
Combretum stylesii grows easily from seed, and is
currently being grown at the Kirstenbosch National
Botanical Garden.
Author:
Marilyn Bodasing, University of KwaZulu-Natal
Photo credits:
David Styles
This article was previously published in the September 2011
issue of the Veld & Flora.
Published in the Dendron with kind permission of the authors.
Die grootste gedeelte van die noordoostelike
Springbokvlakte (Limpopo) word onderlê
deur ‘n substraat van basaltiese lawa en sekondêre
wit kalksteen. Van horison tot horison is dié
wêreld plat. Vorentoe en agtertoe lyk albei ewe
opdraand! Die algehele afwesigheid van panne
en duidelik gedefinieerde waterlope val ‘n mens
dadelik op. Die waterlope bestaan in werklikheid
uit breë, vlak laagtes wat moeilik met die blote oog
waarneembaar is en slegs na groot reëns loop. Die
enigste afwisseling in die gelyk landskap is ‘n breë
strook sand wat die noordelike Vlakte van die suide
skei, die sogenaamde sandbulte.
Die basalt skep ‘n uitgestrekte, struikagtige,
doringboom-oorheersde bosveld op die
kenmerkende basaltiese kleigronde. Groot
gedeeltes is egter al ontbos en vir akkerbou
aangewend of deur ander menslike aktiwiteite
getransformeer. Die geoloog, Wagner (1927) het dit
treffend beskryf: “The flats proper are characterized
by their level nature --- the almost entire lack of well
drained water-courses and their peculiar black and
red soils. They are made up of great expanses of
apparently level grassland and tree steppe --- The
grassland marks the position of the area occupied
by black turf soil. It is normally devoid of trees, but
supports an abundant growth of dwarf bush-like
acacias.”
Die swart turf is ‘n vrugbare, swaar, swakgedreineerde
kleigrond wat in situ ontwikkel het.
Volgens Wagner (1927) is dit ‘n fosfaatryke grond
met sterk rek- en krimpeienskappe: “The black
turf is a heavy residual clay soil of greyish-black
or bluish-black colour, rich in colloids. It swells
very considerably when wetted and on drying
develops gaping shrinkage cracks which divide
into polygonal (veelhoekige) columns. Its marked
fertility is due mainly to the high ratio of available
to total phosphorus. The black turf forms a layer
from 1 to 8 feet in thickness, generally underlain
by nodular calcareous tufa.” Die “colloids” waarna
die outeur verwys staan in Afrikaans bekend as
kolloïdale deeltjies; dit is kleiminerale of organiese
deeltjies met ‘n deursnee van 0.0005 tot 0.000001
mm wat nie in water oplos nie, maar klein genoeg is
om daarin rond te dryf.
Só ‘n plek is Malgas (154 KS, 2429 AC Zebediela-
Wes), suid van Immerpan – ‘n tuiste van die
DIE MAROELABOS VAN TSHIPISE-”DUIN” » Berig op volgende bladsy
DIE INVLOED VAN SWART TURF OP BOOMDIVERSITEIT
Die invloed van swart turf op boomdiversiteit
te Malgas, Noordoostelike Springbokvlakte
Nico Hager
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blaasdoring (Acacia luederitzii var. retinens) en
‘n paar ander wat dié grondsoort se gelyke is.
Die agtervoegsel “-pan” in Immerpan verwys nie
na ‘n pan in die werklike sin van die woord nie.
Volgens Wagner (1927) is daar geen panne op die
basaltgedeeltes van die Vlakte nie: “The complete
absence of pans is the more remarkable as they
are fairly common on the sand-bults.” ‘n Ondersoek
van die S.A. 1:50 000 Topo-kadastrale kaarte van
die gebied bevestig inderdaad hul afwesigheid.
Desondanks is daar talle plase op die turfvlaktes
met “pan”-name, bv. Klippan (521), Rooipan (508),
Vlakpan (509), Mooipan (519), Turfpan (943),
Zandpan (1048) en Kalkpan (127). Immerpan is ‘n
spoorweghalte op Brakfontein (152). Waarskynlik
het hierdie ou plaasname uit die dae van die ZAR
hul oorsprong in die vlak, breë, stadigvloeiende
waterlope, wat na groot reëns soos panne lyk.
Nie elke boom wat op ander grondsoorte in die
omgewing gedy, aard egter op Malgas se swart
turf nie. As voorbeelde, uit die omgewing, van
bome wat glad nie op swart turf kan aanpas nie,
kan die vaalboom (Terminalia sericea) en die
wilde-sering (Burkea africana) genoem word.
Hierdie twee is ware sandliefhebbers. ‘n Boom
se verspreidingspotensiaal word beperk as ‘n
lewensbelangrike omgewingsfaktor buite sy
verdraagsaamheidsgrense val, of indien dit sy
vermoë om te kompeteer, strem (Van Wyk, 1982).
In hierdie geval is die grond, die swart turf, met sy
besondere chemiese en fisiese eienskappe, die
beperkende faktor.
Tog is daar bome, soos die fyndoring (Acacia
tenuispina), wat uitsluitlik met swart turf assosieer.
Sulke bome is turfspesialiste. Tussen die uiterstes
van turfliefhebbers en -haters is daar ook die
veelsydiges (generaliste) wat op meerdere
grondsoorte deug. As voorbeelde van sulke
bome, wat op Malgas voorkom, kan die swarthaak
(Acacia mellifera subsp. detinens) en witgat (Boscia
albitrunca) genoem word. Dit is gewoonlik bome
met groot verspreidingsgebiede.
Dat die swart turf die verspreiding van verreweg die
meeste van die omgewing se bome daarop inhibeer,
word deur die feite gestaaf. Op Malgas kom net
16 soorte voor, terwyl daar op Vuursteenlaagte,
5 kilometer daarvandaan, op sand, 73 is. Dié
opvallende verskil in diversiteit kan net toegeskryf
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62
FIG 1
Stam en bas van die blasadoring
FIG 3
jong, hangende blaasdoringpeule
FIG 5
Stammetjies, dorings en blare van die fyndoring
FIG 7
Swartstorm
FIG 9
Blomme van die swartstorm
FIG 2
Normale en geswolle dorings van die blaasdoring
FIG 4
Fyndoring
FIG 6
Hangende fyndoringpeule
FIG 8
Stam en bas van die swartstorm
FIG 10
Veelhoekige kolommetjies in uitgedroogde swart turf
word aan die verskil in grondsoort. Alle ander
omgewingsfaktore is immers op so ‘n kort afstand,
oor gelyk grond, een en dieselfde.
Anders as wat ‘n mens intuïtief sou verwag,
onderhou arm sandgronde ‘n veel groter
verskeidenheid bome as vrugbare kleigronde.
Vrugbare gronde is hoofsaaklik afkomstig van
basiese, vulkaniese gesteentes (moedermateriaal),
soos basalte, gabbro’s en doleriete. Hierteenoor
is arm sandgronde, asook windafsettings van
Kalaharisand, afkomstig van sandsteen (soos
op Vuursteenlaagte), en oppervlaktesand
afkomstig van graniete en gneise (soos op
die Nebo-plato) (Scholes, 1990). Die rede vir
die verskil in vrugbaarheid is dat sand, weens
gebrek aan kleiminerale, vinniger dreineer en
plantvoedingstowwe daardeur uitgeloog word,
terwyl klei stadig dreineer en voedingstowwe
behou. In Suid-Afrika onderskei ons gewoonlik
ook tussen plantegroei op voedingstofryke, warm,
laagliggende gronde en arm, koeler, hoogliggende
gronde as onderskeidelik soetveld en suurveld.
Intermediêre toestande word dan gemengde (bos)
veld genoem.
‘n Tweede verskynsel, wat verbandhou met
grondvrugbaarheid, is dat boombevolkings
op hoërliggende, goed-gedreineerde en arm
sandgronde (soos in die Waterberg) breëblaargedomineerd
is (veral lede van die Combretaceae
en Caesalpiniaceae), terwyl bevolkings op
laagliggende, swak-gedreineerde, vrugbare en
kalkryke kleigronde (soos op die Springbokvlakte)
mikrofillies of fynblaar-gedomineerd is (veral lede
van die Mimosaceae) (Scholes, 1990; Coetzee e.a.,
1977). Selfs die bome se verdedigingstrategieë
teen blaarvreters volg min of meer die
grondvrugbaarheidspatrone van die bosveld:
chemies (tannien) op arm gronde; struktureel
(dorings) op vrugbare gronde (Scholes, 1990).
Die voor die hand liggende vraag is wat die rede(s)
vir dié ”eienaardige” verspreidingsgedrag van die
bome is? Hoewel die verskil in boomdiversiteit
tussen klei- en sandgronde welbekend is, is daar
nogtans min daaroor gepubliseer. Volgens die
beskikbare literatuur oor die onderwerp berus dit
egter bloot op die bome se natuurlike reaksies op
gegewe omgewingsfaktore.
Soos reeds genoem, penetreer en filtreer water
maklik deur sand. Hierteenoor absorbeer klei water
stadig, wat waterverlies deur afvloei en verdamping
meebring (Scholes, 1990). Plantvoedingstowwe
word op dié wyse maklik uitgeloog in sand,
maar bly behoue in klei. Daarom is kleigronde,
DIE INVLOED VAN SWART TURF OP BOOMDIVERSITEIT
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soos die swart turf van die Springbokvlakte, baie
vrugbaar. Hoewel klei vog vir lang tye behou, kan
boomwortels dit nie maklik opneem nie omdat die
water stewig aan die kleideeltjies vaskleef. Bome
op kleigronde verkry nietemin steeds genoeg
voedingstowwe, danksy die vrugbaarheid van die
grond. Bome op sandgronde moet egter groter
hoeveelhede water absorbeer om in hul minerale
voedingstofbehoeftes te voorsien. Om dan weer
van die oortollige water ontslae te raak, het hulle
(in die algemeen) breë (groot) blare om vinniger
te kan transpireer, terwyl bome op kleigronde
eerder die skaars water moet bespaar en daarom
klein blaartjies het (Grant & Thomas, 2000). Bome
is dus aangepas by hul natuurlike omgewings om
dit ten beste te benut.
Dit verduidelik natuurlik nog nie wat die
“verdwerging” van die bome op die swart turf
van die Springbokvlakte, in weerwil van hul
veelgeroemde vrugbaarheid, veroorsaak nie. Wat
gebeur, is dat die rek- en krimpbewegings van die
klei, in reaksie op benatting en uitdroging, die bome
se wortels beskadig. Die skade wat hierdie eienskap
van turf aan mensgemaakte strukture kan aanrig, is
welbekend. Die potensiële uitsetting (en inkrimping)
van turf wissel van plek tot plek, afhangende van
faktore soos gronddiepte, maar kan baie groot wees.
Wagner (1927) het dit bloot as “very considerable”
beskryf. Te oordeel aan die “golwe” wat ‘n mens
soms op teerpaaie wat op turf gebou is, sien (bv. op
die Roedtan-Potgietersruspad), kan dit aansienlik
wees. Volgens Van der Merwe (1964) is opwellings
(heaves) van 80–100 mm algemeen vir swart turf,
maar vertikale bewegings van meer as 300 mm is
moontlik en op Lethabo is opwellings van meer as
500 mm op alluviale gronde aangeteken. Dit verg
dus geen besonderse verbeelding om ‘n begrip te
vorm van die kragte waaraan boomwortels, veral
haarwortels, in swart turf blootgestel is nie. ‘n Mens
kan maar sê hulle word voortdurend “gesnoei”. Die
gevolg is ‘n natuurlike verdwergde groeivorm, net
soos wat die kunsmatige snoei van wortels ook deur
die mens gebruik word om bonsai-plante te skep.
Dit hang dus waarskynlik van ‘n boom se
lewenskragtigheid en herstelvermoë af of dit
die mas op swart turf, soos die van Malgas, sal
opkom of nie. Weinig beskik blykbaar oor dié
vermoëns. Bome wat dit wel het of selfs turf bo
ander grondsoorte verkies, is soos gemeld,
turfspesialiste. Net twee van Malgas se bome
kan beskou word as egte turfspesialiste: die
blaasdoring en die fyndoring. Die ander sien ‘n
mens ook in gemengde bosveld en op sand, selfs
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DIE INVLOED VAN SWART TURF OP BOOMDIVERSITEIT
Kalaharisand (bv. swarthaak). Dit is nie duidelik
waarom turfspesialiste nie op sandgronde vestig nie.
Een moontlikheid is dat die bome swak met ander
bome kompeteer en daarom die gespesialiseerde
turfhabitat (waarby min bome aangepas is) verkies.
Ongeveer 80 uit elke 100 bome op Malgas
is ‘n blaasdoring. Vir hom beteken die swart
turf die lewe. Die blaasdoring is meestal ‘n
laagvertakkende, meerstammige haakbos met kort,
gepaarde haakdorings en enkele groot, wit, reguit,
opgeblaasde dorings, amper soos die dorings
wat ‘n mens soms aan die Nataldoring (Acacia
natalitia) sien, net korter. Die oningewyde sien hom
maklik vir iets anders aan, totdat die onverwagte
aanskoue van die bolmagie-dorings, saam met
die “normales” aan een en dieselfde tak, sy ware
identiteit met verbasing tuisbring. Soms ontbreek
die grootdorings geheel en al, veral by ouer bome.
Laasgenoemde eksemplare is enkelstammig en tot
7 m hoog.
Volgens Ross (1979, p. 12) is die geswolle dorings
nie insekgalle nie, maar ‘n normale produk van
die boom self. Wipstertmiere maak egter soms
nes in die dorings en is na bewering vir die
boom tot nut. Die blaasdoring se tweelingbroer,
die Kalaharidoring (Acacia luederitzii var.
luederitzii), wat nie opgeblaasde dorings het nie,
verkies uitsluitlik die Kalahari se sand, met net ‘n
beperkte verspreiding duskant die suidoostelike
Botswanagrens (steeds op Kalaharisand). Die feit
dat dié grootboet Kalaharisand, in teenstelling met
turf verkies, laat ‘n mens wonder of die twee werklik
net variëteite of selfs subspesies is en nie eerder
volwaardige afsonderlike spesies is nie?
‘n Yl, lang en fyndoringrige struikie, wat uitsluitlik
op swart turf tuis is, is die fyndoring. Een van
sy ander name is inderdaad turfdoring. Hierdie
kleintjie is ‘n ware turfliefhebber en jy sal hom nie
kry, tensy jy hom op swart turf soek nie. Op Malgas
staan dit plek-plek op versteurde grond so dig dat
dit van stap ‘n beproewing maak. Die fyndoring is
die enigste plant, behalwe die enkele kanferbos
(Tarchonanthus camphoratus) hier en daar, wat
op die hope bogrond van die ongerehabiliteerde
Malgasse kalkgroewe van weleer floreer.
Dié meerstammige doringboompie (meer struik as
boom) spruit vanuit ‘n meerjarige, ondergrondse
wortelstelsel (Palgrave, 2002) met gladde, persbruin
stammetjies so dik soos ‘n potlood of jou vinger. Dit
kan ‘n meter of twee hoog word. Ou stammetjies
gaan lê later almal na die een kant toe soos iets
wat geswik het en gaan dan dood. Soos die naam
sê, is die dorings lank en fyn (dun) en wys terug
na die hoofstamme. Die blomme is in digte eiergeel
bolletjies gerangskik. Die klewerige peule is kort,
plat, geboë en oortrek met swart kliertjies. Op ‘n
afstand kan hy jou moontlik mislei om hom aan te
sien vir ‘n plaat jong soetdorings (Acacia karroo),
maar van naderby is die verskille baie duidelik.
Byvoorbeeld, die soetdoring se peule is nie
klewerig nie en sonder die swart kliertjies. Omdat
die fyndoring so puntenerig is oor die tipe grond
loop mense soms ‘n leeftyd lank in die veld rond
sonder om hom ooit te ken.
Een van Malgas se struike wat dikwels met diep,
swaar kleigronde geassosieer is, maar nie werklik
‘n getroue turfliefhebber is nie, is die swartstorm
(Cadaba aphylla), want hy het twee liefdes --- turf
én kalksteen. Elders in Suid-Afrika sien ‘n mens dit
dikwels in nate en skeure van kaal kalksteenkranse
(bv. op die Ghaapse plato). Die vraag is nou of hy
op die Springbokvlakte se turfvlaktes tuis is oor die
hondjie of die halsbandjie, die turf of die kalk? Ten
spyte van sy groot verspreidingsgebied is hy tog nie
orals te vinde nie as gevolg van sy sterk voorkeure
vir grondtipe.
Soos die spesifieke naam aphylla aandui, is die
plant blaarloos, behalwe in saailinge of aan baie
jong takkies. Die algemene voorkoms is die van ‘n
slordige, stekelrige bos wat ietwat aan ‘n ystervark
herinner. Die takkies is blougroen; die blommetjies
pragtig rooi met die meeldrade op die punt van ‘n
lang steeltjie en die vruggies wurmagtig, amper
soos die knoppiesboontjie (Maerua angolensis) s’n,
net kleiner. Aanvanklik staan of lê hy op die grond,
maar ouer plante het plat, swart stamme waarmee
hulle in bome oprank of opleun en wat soos ‘n
bobbejaan se arm lyk, kompleet met skielike, skerp
buig en al, nes ‘n elmboog. Vandaar die paslike
alternatiewe volksnaam, bobbejaanarm.
Enigeen wat ‘n aftrekstel van die swartstorm se wortel
as purgeermiddel ingekry het, staar na bewering ‘n
moeilike tyd in die gesig! Hierdie ekstremiteit was
ook die aanleiding tot die uitsonderlike naam: “The
vernacular name is an allusion to the black colour
of the bark of the root and the “stormy” action of
the bark in decotions when taken as a purgative.”
(Smith, 1966).
Behalwe voormelde drie soorte kom die volgende
bome en groter struike ook op Malgas se swart turf
voor:
Boscia albitrunca;
B. foetida subsp. rehmanniana;
Acacia karroo;
A. mellifera subsp. detinens;
A. tortillis subsp. heteracantha;
Searsia engleri;
S. pyroides;
Ziziphus mucronata;
Grewia flava;
Combretum hereroense subsp. hereroense var.
hereroense;
Euclea undulata;
Ehretia rigida subsp. nervifolia; en
Tarchonanthus camphoratus.
Dit sou onvolledig wees om nie ook van die
dominante grasse te vermeld nie, want die Vlakte se
swart turf is graswêreld. Die gras wat Wagner (1927)
so geïmponeer het, is waarskynlik witbuffelsgras
(Panicum coloratum var. coloratum). Ook dit groei
by voorkeur op swaar, vrugbare gronde (Van
Oudtshoorn, 1994). ‘n Bees wat daarop loop, word
spekvet (pers. med. mnr. J.S. Venter).
Ten spyte van die beperkte boomverskeidenheid
is die veld op die swart turfvlaktes van die
Springbokvlakte uit ‘n boerdery oogpunt alles
behalwe minderwaardig vergeleke by ander
veldtipes van die Bosveld. Die veld is soet, die grond
vrugbaar, die drakrag hoog en die plek het sy eie
bekoring en mistiek. En as jy nog nie die blaas- of
fyndoring gesien het nie, soek hulle gerus op die
swart turfvlaktes van die Springbokvlakte op plekke
soos Malgas.
FOTOS:
Mnr. Dick Duncan
ERKENNINGS:
Dank is verskuldig aan mnr. Koos Venter vir die
beskikbaarstelling van sy fasiliteite; aan dr. Phil Paige-Green
van die WNNR en mnr. Peter Day van Jones & Wagener vir
DIE INVLOED VAN SWART TURF OP BOOMDIVERSITEIT
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inligting; aan prof. S.W. Jacobsz van UP vir die verkryging
van ‘n literatuurbron; en aan prof. Braam van Wyk van UP vir
aanmoediging om die artikel te skryf, vir inligting en vir die
kontrolering van die manuskrip.
BRONNELYS:
1. COETZEE, B.J., VAN DER MEULEN, F., ZWANZIGER, S.,
GONSALVES, P. & WEISSER, P.J. 1977. A phytosociological
classification of the Nylsvley Nature Reserve. CSIR,
Pretoria.
2. GRANT, R. & THOMAS, V. 2002. Sappi tree spotting
Bushveld. Jacana Education Ltd, Johannesburg.
3. PALGRAVE, M.C. 2002. Trees of Southern Africa, Third
edition. Struik Publishers, Cape Town.
4. ROSS, J.H. 1979. A conspectus of the African Acacia
species. Memoirs of the Botanical Survey of South Africa.
Botanical Research Institute, Pretoria.
5. SCHOLES, R.J. 1990. The influence of soil fertility on the
ecology of Southern African dry savannas. Journal of
Biogeography 17 (4/5): 415–419.
6. SMITH, C.A. 1966. Common names of South African
plants. Government Printer, Pretoria.
7. VAN DER MERWE, D.H. 1964. The prediction of heave
from the plasticity index and percentage clay fraction
in soils. The Civil Engineer in South Africa, June 1964:
103–107.
8. VAN OUDTSHOORN, F.P. 1994. Gids tot grasse van Suid-
Afrika. Briza Publikasies, Arcadia, Pretoria.
9. VAN WYK, A.E. 1982. Seldsame Bome –
10.
Verspreidingsfaktore, Dendrologiese Tydskrif 2 (1 & 2):
3 – 24.
WAGNER, P.A. 1927. The geology of the north-eastern
part of the Springbok Flats and surrounding country.
Geological Survey. Government Printer, Pretoria.
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DENDRON » No/Nr: 43 » November 2011

WHITE PEAR Apodytes dimidiata » Foto: Naas Grové
STINKWOOD ocotea bullata » Photo: Naas Grové
group of 26 members of the Outeniqua
A branch of the Dendrological Society and
two members of the fledgling Worcester section
visited Grootvadersbos over the weekend of 10-11
September, 2011. We were ably guided by Pierre
van den Berg (ex Cape Nature) and the extremely
competent and amiable Goliath Highburg, a serving
Field Ranger at Cape Nature, known affectionately
as “Twakkies”. The forest represents the southwestern
most vestige of Afromontane forest which
had earlier occupied vast areas of the southern
Cape. Grootvadersbos had mercifully been spared
the most severe fires and more importantly, the
insatiable woodcutters’ axes. Secure from utter
devastation from the harvesters, partially on account
of its inaccessibility and the fact that it could recover
from exploitation owing to its good rainfall, seclusion
in a deep kloof where soil is fertile and fires do not
penetrate so easily, the forest has survived and
matured to reveal some excellent examples of
some of the southern Cape’s signal Afromontane
species. Control measures undertaken at first by
the Department of Forestry and later Cape Nature
have meant the forest is now in good hands and
thriving.
Of the official list of 46 common tree species
which can be found in the forest, the group had the
opportunity of viewing 34 at close range.
A key species in the forest is Olea capensis subsp.
macrocarpa (Ironwood). This species is abundantly
evident throughout the forest and the towering size
of the specimens viewed, left the group with little
more than a good feeling for the greyish bark with
its indentations, an occasional “crocodile skin-like”
appearance and sporadic black “oozes”, which seem
to occur anywhere on the trees, but more particularly
where a wound has occurred in the bark.
Notable of the species found in the forest are the
various “pear” species. These trees are notoriously
difficult to separate, but the group could get a
true feel for the subtle differences between these
species. To start with, Olinia ventosa (Hard Pear)
was in full flower with small posies of yellow
flowerets (similar to the smaller clusters of flowers
on the Cherry/Candlewoods which were also in
flower). The bark was shown to be reddish-brown
and deeply fissured lengthways. In contrast Scalopia
byeenkomste
events
Grootvadersbos excursion
Robert Smith - September, Grootvadersbos
mundii, (Red Pear) was pointed out on a number of
occasions. Many of these trees have survived to
become excellent soaring canopy specimens; not
the “small to medium sized” trees which the field
guides would have you believe. On account of their
cathedral-like growth, the stems have a definitive
smooth but mostly blistering bark structure,
where the blisters hang downwards and not in
any direction as in Podacarpus falcatus (Outeniqua
Yellowwood). More often than not, while marvelling
at the various specimens in this forest of superb tall
canopy trees, the bark and stems are all one has to
go by to determine the species! Alas, no specimens
of Apodites dimidiata (White pear) could be found.
On the south facing slopes of the forest, good
sightings of Cunonia capensis (Red Alder) could
be had. Some of these specimens were truly awe
inspiring. One in particular was situated near the
canopy bird hide and its presence alongside a
marvellous example of a coppiced Ocotea bullata
(Stinkwood) which had sent up its rescue shoots
to the canopy in defiance of the otherwise mortal
wound which it had suffered sometime in its troubled
past, left one with a true sense of amazement at these
spectacular trees. This canopy is also shared with
a number of introduced California Redwoods and
together with Podocarpus falcatus and Podocarpus
latifolious (Outeniqua and Real Yellowwood) one
has a magnificent feeling for this great forest. The
haunting song of Narina trogons (two people were
lucky enough to see one) and the fleeting twitters
of Cape White-eyes, Greater Double-collared
Sunbirds and Blue-mantled Crested Flycatchers,
seem to bear out the fact that the area is well
appreciated by the locals!
While it would be impossible to mention all species
encountered in this forest, it is with conviction that
one can say that the visit was well worth the effort
and every hope is that it will continue to survive and
grow under the ongoing care and dedication of the
officials of Cape Nature.
The group would like to record their appreciation
of the excellent cottage facilities on Honeywood
farm run by Miranda and John Moodie next door to
Grootvadersbos.
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BIG TREE COMPETITION 2011
Grootboommeet-kompetisie
in samewerking met RSG
Redakteur - namens die Sentrale Komitee
Ons het ‘n wonderlike reaksie gehad deur oor die 70 inskrywings vir die eerste Grootboommeet-kompetisie
te ontvang. Ons het die voorreg gehad om saam met RSG lugtyd te kry om die nuus te verspei en so ook
bewustheid oor die Dendrologiese Vereniging en sy missie aan te spoor.
Daar was twee kategorieë om van te kies tydens die boommeet kompetisie. Die eerste kategorie was vir die meet
en opname van groot bome met die grootste stamomtrek op borshoogte. Vir hiérdie kategorie kon drie wenners
elk ‘n kopie, geteken deur die outeurs van Dictionary of Names of South African Trees (Prof AB van Wyk, Dr Erika
van den Berg, Meg Coates-Palgrave & Marie Jordaan, 2011. BRIZA, PLUS ) ontvang, asook ‘n uitgawe van Green
heritage: trees, forests and woodlands of South Africa (Department of Agriculture, Forestry & Fisheries, 2011).
Die tweede kategorie was vir die meet en opname van uitsonderlike bome. Tien wenners kon elk ’n kopie
van Field Guide to Trees of Southern Africa (Prof. Braam van Wyk & Piet van Wyk. 1997, Struik Publishers, Cape
Town PLUS) asook ‘n uitgawe van Green heritage: trees, forests and woodlands of South Africa (Department of
Agriculture, Forestry & Fisheries, 2011) ontvang.
Kategorie 1
Groot bome met die grootste stamomtrek op borshoogte
Eerste Prys:
Dr. Francois du Randt van Hluhluwe in Kwa-Zulu Natal het nie minder nie as 33 spesies opgemeet. Wat hierdie
bydrae besonder maak is dat hy oor ongeveer 23 jaar die groei patroon van onder andere talle voorbeelde
van die Newtonia hildebrandtii var. hildebrandtii (Lebombo-wattel, endemies aan die streek) opgemeet en
gedokumenteer het. Hy het die volledige lys van bome wat hy opgemeet het aan die Vereniging beskikbaar
gestel sodat dit in die Nasionale Register van Grootbome in Suid-Afrika opgeneem kan word. Twee van die
grootste Lebombo-wattels wat hy opgemeet het se stamomtrek by borshoogte is onderskeidelik 8,80m en 7,40m.
Interessante afleidings wat hy die afgelope 23 jaar gemaak het sluit in en ek haal hom aan:
Die Lebombo-wattel bome
begin krimp voordat hulle doodgaan.Die bome groei nie eweredig oor die jare
nie – dit het waarskynlik te doen met die wisselende reënval. Ons kan aflei, mits die
bome eweredig gegroei het dat hulle maklik tussen 500 en 800 jaar oud kan wees.
Ekstrapoleer hierdie inligting op ‘n grafiek en kyk na die afleidings! Dit lyk amper asof
die gemiddelde Newtonia spp ongeveer 0,5 cm per jaar dikker word, maar natuurlik
is daar ‘n hordes ander faktore, soos hoogte van die boom, en so meer.
Tweede Prys:
Mnr. Chris jordaan van Kenhardt wat vir ons ‘n baie interessante opmeting van ‘n Acacia erioloba (kameeldoring)
met 6 stamme ingestuur het. Die boom het ‘n baie groot basis wat op 1 – 1,2m vertak. Chris het al die stamme by
1,4m kon opmeet. Hy laat weet ook dat ‘n kleinerige tent opgeslaan kan word tussen die stamme bo-op die basis
van die boom. Die gesamentlike omtrek van die ses stamme is 13,6m!
Derde Prys:
Me. Linda Retief van Smithfield wat ‘n Olea europaea subsp. africana (olienhout) met 14 stamme opgemeet het.
Die totale stamomtrek by borshoogte is ‘n allemintige 10,15m.
Kategorie 2
Uitsonderlike bome opgemeet
1
2
3
4
5
6
7
8
9
10
BIG TREE COMPETITION 2011
Mnr. Wynand Breytenbach van Montanapark het ‘n Diospyros mespiliformis (jakkalsbessie) met ‘n
stamomtrek van 6,34m opgemeet.
Mnr. Gideon Odendaal van Polokwane het ‘n twee-stam Boscia albitunca (witgat) met ‘n stamomtrek
van 4,06m opgemeet.
Mnr. Deon den Hartog van Die Boord, Stellenbosh het ‘n Erythrina caffra (Kaapse koraalboom)
met ‘n stamomtrek van 4,91m opgemeet.
Mnr. Carel Erasmus van Stellenbosh het ‘n Maytenus oleoides (klip-kershout) met vier stamme
opgemeet. Die gesamentlike stamomtrek by borshoogte is 8,9m.
Me. Lisa Martus van Haenertsburg het ‘n Cussonia spicata (kiepersol) met ‘n stamomtrek van
9,65m opgemeet.
Me. Ronel Eksteen van Mookgophong het ‘n Searsia lancea (karee) met ‘n stamomtrek van 6.69m
opgemeet.
Glenwood House School in George het as skoolprojek 6 bome opgemeet. Dit is die enigste skool
wat ingeskryf het en omdat ons juis die liefde en kennis van bome onder die jeug wil bevorder, is hulle
ook wenners.
Mnr. Willem van jaarsveld van Annlin het ‘n Dovyalis zeyheri (wilde-appelkoos) met ‘n stamomtrek
van 2,94m opgemeet.
Mnr. Kambro Swanepoel van Oudtshoorn het ‘n Ficus burkei (gewone wildevy) met ‘n stamomtrek
van 9,55m opgemeet
Mnr. Gerbie Strydom van Baltimore het ‘n Acacia erioloba (kameeldoring) met ‘n stamomtrek van 4,25m
opgemeet. Hierdie is waarskylik die grootste kameeldoringboom in die westelike bosveld.
Atalaya Branch Calendar 2012
byeenkomste
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Beautiful photographic calendar for 2012 printed on high quality
photographic quality paper and nicely bound. It contains one
photo per month including a short story about the subject matter.
Six photos are in portrait and six in landscape, so some will have
the dates and info along the sides and some along the bottom.
Get it at: Fogarty’s Bookshop or contact
Lloyd Edwards at raggycharters@gmail.com
A3 size A4 size
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DENDRON » No/Nr: 43 » November 2011

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BERIGTE
Boomplantfunksie saam met Solidariteit Helpende Hand
Izak van der Merwe - Filadelfia
Mnr. Dirk Hermann het in Kameeldrif- Wes naby Pretoria het homself en sy grond toegewy aan die bediening en
huisvesting van arm blanke gesinne. Hierdie projek, bekend as Filadelfia Ark, huisves reeds ‘n aantal mense wat
ook werk gebied word in onder meer ‘n kombuis wat tuisgebak maak en verkoop, en ‘n aanleg waar bitumen
pakkies vervaardig en aan munisipaliteite verkoop word om slaggate mee te vul.
Op 23 September het die Dendrologiese Vereniging in samewerking met Solidariteit Helpende Hand en die
NG Gemeente Lynnwoodweg inheemse bome geplant by die sowat 50 nuwe Wendyhuise wat op die terrein vir
huisvesting opgerig word. Hierdie bome sal mettertyd koelte verskaf en die omgewing verfraai. Professor Andre
de Villiers, voorsitter van die Magaliestak, het tydens die geleentheid gepraat oor die belangrike rol wat bome
in ons kultuurerfenis speel, aangesien die geleentheid saamgeval het met Erfenisdag.
Die geharde boomsoorte wat geplant is was versigtig geselekteer om die harde omgewingstoestande van
winterryp en kleigronde te oorleef. Die Vereniging lewer in Desember nog vrugtebome by Filadelfia Ark af.
Dendrological Society Pays for Radar Scan of Tree Giant
Izak van der Merwe
The Woodville Big Tree is a giant Outeniqua yellowwood (Podocarpus falcatus) standing in the Knysna forests near
George. This tree has a trunk circumference of 8.9m and a height of about 33m. It has been declared a Champion
Tree, and receives thousands of visitors per year. Members of the Dendrological Society raised a concern about
the condition of the tree, since considerable crown die-back could be observed. It was then decided to spend
a part of funds raised specifically for conservation projects on a crown inspection by an arboriculturalist and a
high-tech radar scan of the tree trunk to detect whether there might be tree-rot, in which case special measures
would have to be taken to save the tree. Such surveys are expensive, and securing government funding for tree
conservation activities of this nature is seriously hampered by red tape.
On 28 June 2011 a member of the Central Committee of the Society joined Mr Daan Loock, an arboriculturist of
Arbor Oxygen based in Australia, in his investigation of the tree. The radar scan with a tomograph fortunately
indicated no major internal decay requiring urgent action. There are signs of outer decay that has to be monitored,
with removal of some dead wood recommended. The creation of a larger boardwalk area around the tree was
also recommended, to prevent further compaction of soil around the tree.
On 15 August 2011 tree climber, Leon Visser
from Trees Unlimited in Stellenbosch scaled and
measured a Sydney gum tree (Eucalyptus saligna),
which turned out to be a new African tree height
record. This tree towers above a stand of gum
trees planted in 1906 in the Woodbush Forest
Estate, Limpopo Province. The tree climb formed
part of a tree measuring expedition organised
by the Department of Agriculture, Forestry and
Fisheries, sponsored by Stihl South Africa. Three
giant Mexican Pine trees (Pinus oocarpa) were also
climbed, the tallest of which measured at over 50
metres tall. These sturdy trees with trunks of just
under 5 metres in circumference, were dubbed
“The Three Matrons”. Few pine trees anywhere in
the world reach such dimensions. The pine trees,
like their gum tree counterparts nearby, are already
New Africa Tree Record
Adopted from a Press Release by Daff
more than a century old. According to the planting
records they were planted a year before the gum
trees.
The Sydney gum tree, measured at over 80 metres,
breaks the previous South African tree height record
held by two gum trees, known as the “Twin Giants
of Magoebaskloof”, by just a metre. It stands so
close to the twin trees such that their crowns almost
touch. The trio of world-class champions may now
be called “The Magoebaskloof Triplets”, officially
the tallest trees in Africa, and also the tallest planted
trees in the world. The Department protects the tree
stand as a whole as a grove of Champion Trees,
which is managed by Komatiland Forests.