Acacia cyclops A. Cunn. ex G. Don
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Producing a dense high quality firewood, this species has been recommended for
stabilization of coastal dunes. Goats and antelope browse the phyllodes. The
seeds and their oily funicles are eaten by birds, primates, and rodents, and if
crushed, might be suitable for cattle.
With its high tannin content, the species could serve as an astringent.
Bark has yielded 6.5% tannin, or in Natal, up to 12.1%. Seed contains 10% of
fixed oil, the aril or funicle 40%.
Dense, evergreen bushy shrub, often multistemmed, or small tree 3 to 8 m tall,
with a rounded crown . In windy coastal sites it forms a hedge less than 0.5 m
high. The foliage comprises light green phyllodes, varnished when young, and
growing in a downward vertical position. Pods, maturing in summer, are not
shed, but remain on the tree, exposing the seeds to predators and dispersers.
Reported from the Australian Center of Diversity, Acacia cyclops is
reported to tolerate drought, salt, sand, weed, and wind.
Native to southwestern Australia, where it grows mostly on coastal sand dunes.
Used for stabilization in South Africa, it is spreading on sand and sandstone
into coastal bush and heathland. This is an extremely weedy species spread by
birds into indigenous vegetation. Once established, it is difficult to remove
or replace. There is little vegetation cover beneath an Acacia cyclops
thicket. The seeds remain viable in the soil for many years. It is relatively
Acacia cyclops can grow in dry areas with annual precipitation less than
300 mm. Tolerating salt spray, wind, sand-blast, or salinity, it is useful for
dune stabilization. This species has a high light demand; it will not survive
in deep shade. Monthly temperature means within the distribution range of this
species vary from 5°C in winter to 31°C in summer. It is slightly
resistant to frost. The species is generally found below 300 m altitude where
annual rainfall is 200 to 800 mm. It grows on quartzitic or calcareous sand or
limestone. It also is found in drier sites such as dune crests (NAS, 1980a).
Direct sowing of pretreated seed is recommended (NAS, 1980a). Seed are treated
with abrasion, acid, and hot water treatment.
Trees may be harvested as needed. This species rarely coppices, and mature
trees do not survive felling. The pods are nondeciduous and are therefore not
easily gathered. Unlike many Acacia species, it is not considered a
valuable tannin or gum producer (NAS, 1980a).
Standing biomass of Acacia cyclops in the southwestern cape of Africa,
where it is replacing indigenous Fynbos vegetation and coastal shrub
communities, was 131 MT/ha. Of this, the litterfall was said to represent 7.4%
of the total biomass, 21.2% of the canopy mass.
Recommended by the NAS (1980a) as a firewood source. The wood is dense, the
logs rarely exceeding 20 cm in diameter. It is a very popular firewood in
South Africa, sold regularly in Cape Town. The annual litterfall of four
Acacia species naturalized in the South African Cape, comprising 60% foliage
and 30% reproductive structures, averages 7 MT/ha, double the value expected in
evergreen scrub communities in winter rainfall regions. Standing biomass in
the Acacia thickets is ca 10 times greater than that of mature Fynbos
(1126 MT/ha) and shrublands in other Mediterranean climates (1530 MT/ha).
Acacias lose ca 10% of their standing crop annually as litter, at a rate
34 times that of the Mediterranean heath and shrub communities. The litter
accumulates on the ground. In a mature thicket, the dry mass of the ground
litter per unit area exceeds that of the living canopy. The ground litter
layer runs 1428 MT/ha, which is fairly average by world standards. "The
annual nitrogen and phosphorus input by Acacia litter should be about nine
times as great per unit area as that of Fynbos." Assuming an N content of 1.5%
and a P content of 1.13%, Acacia litter would contribute 105 kg N/ha and
92 kg P. In an area where the annual precipitation averages between 500 and
750 mm/yr and the annual temperature average ranges between 16 and 18°C,
with radiation averaging 450500 Langleys/day (Capetown has an average annual
precipitation of ca 600 mm, average temperature approaching 18°C), the total
annual litterfall is 9,680 kg/ha, with 1.4% as flowers, 35.5% as pods, 5.3% as
seed, 11.3% as twigs, 39.0% as phyllodes, and 7.7% unidentified fragments. The
total standing biomass was 131 MT/ha DM, ±4% (Milton, 1981).
Most African Acacias are thought to be cross pollinated. Pests and diseases
are not an important factor in South Africa; in fact, the lack of seed
destroyers is partly responsible for the weediness of the species. Grazers may
Complete list of references for Duke, Handbook of Energy Crops
- N.A.S. 1980a. Firewood crops. Shrub and tree species for energy production.
National Academy of Sciences, Washington, DC.
- Milton, S.J. 1981. Litterfall. of the exotic acacias in the southeastern cape.
J. S. Afr. Bot. 47(2):147-155.
Last update December 16, 1997