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ForMatForMatForMat
Newsleer of the Research & Training Division, Zimbabwe Forestry Commission
P.O. Box HG 595, Highlands, Harare. Tel: +263-4-496878/9. Fax: +263-4-497070
October 2014
Vol. 14 No. 1
Conservaon of Bivinia jalberi: A special tree of the Nyuni Hills
Background
As one drives southwards from Masvingo town
towards Beitbridge, at the T-juncon about 15 km
before Ngundu Halt on the le side of the road the
signpost to Tokwe-Mukorsi Dam would appear. the dirt
road towards the construcon site of Tokwe-Mukorsi
dam wall would lead to a beauful view of the riverine
vegetaon of Nyuni Hills. These hills are home to Bivin-
ia jalberi, the cobweb seed tree which the locals call
Mutuputupu, a special tree that grows only in the
Ngundu area in Zimbabwe. Scaered pockets of the
tree are found in thickets along the hill slopes. About 8
km from Nyuni Hills are a few other small hills also
providing a habitat for B. jalberi. However, only close
to 20 mature trees sll remain at Dumbuguru and
Bende gap, southwest of Nyuni Hills. This is a clear sign
that B. jalberi, once a common tree in Ngundu area,
is fast becoming exnct. Also growing on hilly slopes
in close associaon with B. jalberi is Androstachys
johnsonii, the iron wood tree. This tree is equally rare
and occurs at low altudes only in the south and east
of the country (Coates-Palgrave, 2002). Both these
trees are in danger from the excessive exploitaon by
villagers in the surrounding neighborhood in
Ngundu. With the construcon of Tokwe-Mukorsi dam
almost reaching compleon, one prays that the hills
will become islands in the dam to become germplasm
hotspots for B. jalberi.
Taxonomy and Distribuon
Bivinia jalberi Tul belongs to the Salicaceae family.
According to Coates-Palgrave (2002), it grows in
evergreen forests, forested ravines and on rocky hill
outcrops in areas of high rainfall and some winter mist
or drizzle. It reaches a height of 20 to 30 m when
mature. B. jalberi is nave to four African countries
namely Kenya, Madagascar, Mozambique and
Zimbabwe. In Zimbabwe, the Internaonal Union on
Conservaon (IUCN) lists the species as near
threatened (IUCN 2013).
In-situ Conservaon
Apart from roune surveys to assess the conserva-
on status of B. jalberi very lile work has been
done in the past to protect the species from over-
exploitaon by local communies. Early conserva-
on eorts for B. jalberi started between 1986 and
1989 driven by communies led by the Forestry
Commission's Conservaon and Extension Division.
The objecve was to plant more trees in and around
the Ngundu area to enrich the natural populaon.
Jephias Mhike (born 1952) , a headman (sadunhu)
under Chief Gororo and Naphet Chihamure (born
1971, son of Chief Madzivire) are the surviving vil-
lage pioneers of tree planng and conservaon of B
jalberi tree conservaon at Ngundu. According to
Naphet, the tree planng project at Banga Irrigaon
Scheme in Chivi started in 1987 with assistance
from the Forestry Commission. They raised both
exoc and indigenous tree seedlings at the nursery.
The Forestry Ocer then, was in charge of the tree
planng project then. Following the 1992 drought
Banga dam dried up and the severe water shortage
forced terminaon of the tree planng project. The
nurseryman was transferred to Chivi, a develop-
ment that impacted negavely on the tree conser-
vaon work. As a result of these early eorts, the
Research and Training Division of the Forestry Com-
mission became more interested in research on the
conservaon of Bivinia jalberi. The tree always has
a straight bole, comparing very well with the fa-
mous gum tree, Eucalyptus species. It also has good
coppicing ability (also very comparable to the gum
tree) and the wood is not suscepble to pest infes-
taon or damage, maybe superior to the gum tree.
Meanwhile researchers from the Forestry Commis-
sion had inuenced the villagers to bar trespassers
from entering the tree’s natural habitat to avoid
unlawful access to germplasm by unauthorized per-
sons and warned the villagers against unauthorized
cung down of these trees. Below is an image
showing a mature B. jalberi tree in the Nyuni Hills
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Fig. 1. Mature B. jalberi tree. Most Mature trees are
characterised by straight stems and can grow to a height of
up to 30 meters.
Fig. 2 Image showing sampling points (numbered) for B. jalberi trees in Ngundu.
Ex-situ: Threats and opportunies for sustainable
conservaon of B. jalberi
B. jalberi is mostly exploited for fencing and roong
poles and general construcon mber by villagers.
However, exploitaon of B. jalberi seems to have
gone unchecked for a long me to the extent that only
a few mature trees are now le in the area. This
requires urgent acon to save the few remaining pop-
ulaons.
Fires caused by human acvies on the hill slopes
contribute a fair share to destrucon of tender saplings
which are regenerang naturally from seed dispersal.
This causes further tree loss. The construcon of Tokwe
Mukorsi dam poses a further threat to the nearby tree
populaons, especially those at Nyuni Hills which are in
the dam (see Fig 2 below). Under unmanaged
condions the species has a very limited geographic
range that favours its growth.
Despite these challenges, the species is quite promising
from a conservaon point of view. It is relavely easy
to propagate through seed and is relavely fast grow-
ing, making it a candidate for ex-situ conservaon. Cut
stumps show good coppicing abilies (see Fig 3). This
means that the tree can also be managed through cop-
ping from stumps of cut trees
Below is a google earth image showing sites where the
remaining B. jalberi populaons sll exist.
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Fig. 3 A Bivinia jalberi stump with coppices
Fig. 4 Nursery stock for establishment of eld gene banks
So what has been done so far?
In 2013, a domescaon and conservaon iniave
was launched to rescue the fast-declining populaon of
B. jalberi. The Zimbabwe Forestry Commission, in
partnership with the World Agroforestry Centre
(ICRAF—Internaonal Centre for Research in Agro-
forestry), embarked on a conservaon programme,
targeng the remaining populaons of B. jalberi in
the Nyuni range in Ngundu. The project is being
conducted under the theme “Methods for
conservaon and sustainable management of genec
resources of important tree species”. Fig. 4 shows
seedlings raised at the Forest Research Centre nursery
in Harare for planng as ex-situ conservaon plots. An
acve ex-situ conservaon programme was launched
to conserve B. jalberi in secure habitats where it is
likely to thrive. A suitable site was idened on the
rocky outcrops in the Nyamukwarara area in the East-
ern Higlands at John Meikle Forest Research Staon, in
Stapleford Estate where environmental condions are
similar to its natural habitat. Here eld gene banks will
be established at John Meikle for ex-situ management
of B. jalberi.
How important is this conservaon eort?
Through collaborave research work between FC and
ICRAF, conservaon of this threatened forest genec
resource can be improved.
This work will have a signicant impact on forest ge-
nec resources and forest biodiversity conservaon
eorts as it will restore the availability of rare and
threatened species therby achieving an ecosystem bal-
ance. Demand for poles for construcon had put more
pressure on the remaining populaons of B jalberi ,
and hopefully this research work will ensure that this
indigenous tree species is conserved for use by future
generaons.
Acknowledgements
Hearelt acknowledgements go to ICRAF’s Gene bank
Fund for nancial support and Forestry Commission for
providing research personnel. Mr. Matarirano (ICRAF
Country Liaison Ocer) and Belinda Machingauta (FEO
for Chivi District) are acknowledged for facilitang lo-
giscal and local project management support and mo-
bilizing communies respecvely.
References
1. Coates Palgrave, M. 2002. Keith Coates-Palgrave
Trees of Southern Africa, 3rd Ed., 2nd Imp. Struik
Publishers, Cape Town
2. IUCN 2013. IUCN Red List of Threatened Spe-
cies. Version 2013.2. <www.iucnredlist.org>.
Downloaded on 26 February 2014.
M.C TEMBANI , L MATARIRANO AND P. MUTETE
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PEST ALERT:
Glycaspis brimblecombei
Red Gum Lerp Psyllid in Zimbabwe.
Glycaspis brimblecombei (Psyllidae, Hemiptera),
commonly referred to as the red gum lerp psyllid, is
a major sap-sucking insect that feeds on eucalypts
leaves. This pest is nave to Australia, but has been
accidentally introduced into the USA (1998), Mexico
(2000), Chile (2002), Brazil (2003), Argenna (2005),
Ecuador (2006), Venezuela (2007), Uruguay (2008)
and Peru (2008). It has also been recently introduced
in Europe in the following countries; Portugal (2007),
Spain (2007), Italy (2010) and France (2011). Zimba-
bwe is now the fourth African country to record red
gum lerp aer it was recorded in Maurius (2001),
Madagascar (2004) and in South Africa (2012).
Red gum lerp psyllid females lay between 45 and
700 eggs in batches or randomly. The eggs are spin-
dle shaped cream or yellow coloured and hatch in 10
to 20 days. They hatch into yellowish orange nymphs
which pierce the plant ssues with their stylets
(mouth parts), feeding on the xylem cells. As the
nymphs feed they secrete honeydew with which
they construct a waxy cover (called a lerp) around
themselves. This waxy cover is whish and conical in
shape and shelters the insects unl the adult stage.
Lerps are the rst visible sign of the presence of the
red gum lerp psyllid infestaon. In Australia there
are two to four generaons per year.
The red gum lerp psyllid is known as an aggressive
insect that spreads rapidly once it is introduced in an
area. Symptoms of its feeding include dropping of
leaves and drying of leading shoots (twig dieback).
Infested leaves are covered with waxy secreons
and honeydew, on which sooty mould grows. Heavy
infestaons can totally defoliate and kill trees. Euca-
lyptus species dier in their suscepbility to aack
by the red gum lerp psyllid, with E. camaldulensis
and E. terecornis being highly suscepble while E.
grandis is reported to be more tolerant.
Both chemical and biological control measures have
been used especially in America in an aempt to con-
trol infestaons of the red gum lerp psyllid. Contact
inseccides are known to be ineecve as the
nymphs are protected by their covers. Systemic insec-
cides have been used with some limited success,
and their use is of limited value in plantaon forestry
due to the high cost. In the USA, natural enemies of
the red gum lerp psyllid were imported from Austral-
ia. One of these, the parasic wasp Psyllaephagus
bliteus (Hymenoptera, Encyrdae) has become estab-
lished in the USA as a biological control agent for the
red gum lerp psyllid.
For the rst me now the red gum lerp psyllid has
been detected in Zimbabwe around Bulawayo. This
could be aributed to increased movement of goods
and people between our countries and across the
globe in the last few decades hence we need to anc-
ipate the arrival of new invasive pest species. New
pests in South Africa oen appear in Zimbabwe soon
aerwards and good examples are the eucalyptus
snout beetle (Gonipterus scutellatus), the bronze bug
(Thaumastocoris peregrinus) and the blue gum Chal-
cid (Leptocybe invasa). Since the rst report of red
gum lerp psyllid in South Africa in 2012 we have been
on alert for the introducon into Zimbabwe and this
rst report in Bulawayo is very recent and currently
we know that it is restricted in Hillside, Matopos and
Chesa reserve.
The red gum lerp psyllid is a serious Eucalyptus pest
hence we need to take stock of all our eucalyptus
planngs to map out the extent of dispersal and chart
a way forward. The sooner new insect pests are de-
tected, the sooner control measures can be imple-
mented. If you see these symptoms on Eucalyptus
(shown in the picture above), or any unusual symp-
toms on your trees, please report it to:
Mr Member Mushongahande
Forestry Research Centre
Box HG 595, Highlands, Harare.
Phone: 04-496878/9; Cell: 0772372660
e-mail: membermushongahande@gmail.com or
member@frchigh.co.zw
The dierent stages of the Red gum lerp psyllid (eggs,
orange nyph, green adult and the waxy lerp
Red Gum lerp psyllid on eucalypts