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The karee is a small to medium sized evergreen tree that usually
grows to a height of 7 m and a width of 7 m but can be larger depending
on environmental factors.
It
is usually a single-stemmed, low branching tree which has a dense,
soft, round canopy. The karee has a course textured bark and on
older specimens it is dark grey or brown in colour while on young
branches and trees it is a reddish brown-colour. The leaves are
trifoliate (a compound leaf with three leaflets), possessing narrowly
lanceolate (lance shaped) leaflets. The leaves are dark green above
and paler green below. They do not have any hairs on them and the
margins of the leaves are entire. The leaves are leathery and are
often sickle shaped.
The small, inconspicuous flowers are presented as much-branched
sprays which are greenish-yellow in colour and are produced from
June until September. The male and female flowers occur on separate
trees. The fruit are small (up to 5mm in diameter), round, slightly
flattened and covered with a thin fleshy layer which is glossy and
yellowish to brown when ripe. The fruits are produced from September
until January.
The word Rhus is probably derived from the Greek word rhodos
which means red and possibly refers to the colour of the fruits
or autumn leaves of Northern Hemisphere Rhus species. The
genus name lancea refers to the lance shaped leaflets.
The karee occurs naturally in Acacia woodland and along
drainage lines, rivers and streams. It is often found growing on
lime rich substrates. The karee occurs from Zambia in the north
to the Western Cape in the south. It is found throughout the Freestate
and in parts of all the other provinces of South Africa except for
KwaZulu-Natal.
The fruit is eaten by birds such as bulbuls, guineafowl and francolins.
Game animals such as kudu, roan antelope and sable browse the leaves
of the tree which can serve as an important food source for them
in times of drought. The sweetly scented flowers attract bees and
other insects to them. Rhus lancea is useful in providing
natural soil stabilisation and increasing infiltration of rainwater
into the soil thus reducing erosion and raising the ground water
table.
The leaves of the karee provide valuable fodder for livestock but
can taint the flavour of milk if eaten in large quantities by dairy
cattle as a result of the resin contained in them. The tree is also
an important source of shade for livestock in certain regions. The
bark, twigs and leaves provide tannin. In the past the hard wood
was used for fence posts, tool handles and parts of wagons. Bowls,
tobacco pipes and bows were also made from the wood. The fruits
are edible and were once used as an important ingredient of mead
or honey beer. The word karee is said to be the original Khoi word
for mead.
Growing Rhus lancea
The karee is an excellent shade tree especially in hot regions
such as the Karoo and Kalahari since it is evergreen and drought
resistant. Rhus lancea does not have an aggressive root system
and can be used near paving and tarred surfaces. Because the karee
is hardy, frost resistant and evergreen, it is ideal for establishing
a protective canopy for frost sensitive and shade loving plants.
It could thus be considered as a possible pioneer plant for establishing
a new forest in an area that receives frost. Rhus lancea
is suitable for use as a large hedge along the boundaries of properties
such as farms because of its dense growth habit. The density of
the plant makes it suitable for use as a screen or barrier against
wind, noise, objectionable views or to provide privacy. The karee
can adapt well to different soils including those that are poorly
drained (which means that it can be planted almost anywhere). Rhus
lancea is therefore ideally suited for use as a street tree.
Aesthetically the karee is a graceful tree possessing a willow-like
appearance due to its drooping habit and this makes it suitable
for use near water e.g. next to a water garden, dam or river.
Rhus lancea can be propagated easily from seed, cuttings
or layers. The ripe seed should be sown in seedling trays using
a good seedling medium and transplanted into bigger containers when
the seedlings reach the two leaf stage. Cuttings can be taken using
young growth from September till October. The tree can grow up to
80 cm a year and is thus fairly fast growing. Because the tree is
both drought and frost resistant it does not require any special
attention once it has established its root system.
Rhus lancea belongs to the family Anacardiaceae (the Mango
family) which is the fourth largest tree family in southern Africa.
This family is composed of at least 80 native tree species. Rhus
is easy to recognise, as the leaves are all trifoliate and have
a resinous smell when crushed. Common edible fruit and seeds that
belong to this family include the mango, pistachio nut and cashew
nut. The resinous substance is poisonous in many species such as
poison ivy.
References
- Coates Palgrave, K. 1983. Trees Of Southern Africa. Struik:
Cape Town.
- Jackson, W. 1990. Origins And Meanings Of Names Of South African
Plant Genera. Rondebosch: University of Cape Town.
- Joffe, P. 1993. The Gardener's Guide To South African Plants.
1st edition, Cape Town: Tafelberg Publishers Limited.
- Thomas, V. & Grant, R. 1998. Sappi Tree Spotting Highveld
And The Drakensberg Tree And Shrub Identification Made Easy.
1st edition, Johannesburg: Jacana.
- Van Wyk, B. & van Wyk, P. 1997. Field Guide To Trees
Of Southern Africa. 1st edition, Cape Town: Struik Publishers.
- Venter, F. & Venter J. 1996. Making The Most Of Indigenous
Trees. 1st edition, Pretoria: Briza Publications.
Marc Stern
Witwatersrand National Botanical Garden
June 2002
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