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Acacia saligna (Labill.) H.Wendl.
Mimosaceae
Orange Wattle
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Uses
- Folk Medicine
- Chemistry
- Description
- Germplasm
- Distribution
- Ecology
- Cultivation
- Harvesting
- Yields and Economics
- Energy
- Biotic Factors
- References
Orange wattle is an extremely rugged tree, adaptable to barren slopes, derelict
land, and exceptionally arid conditions in Australia and North Africa. It
grows rapidly and is used for reclaiming eroded hillsides and wastelands and
for stabilizing drift sands as well as for fuel. This is one of the best woody
species for binding moving sand. It is useful for windbreaks, amenity
plantings, beautification projects, and roadside stabilization in semiarid
regions. The leaves, or phyllodes, are palatable to livestock when fresh or
dried into hay, especially used as supplementary feed for sheep and goats.
Crushed seeds have been fed to sheep without ill effects. Regrowth of
established bushes is so good that Acacia saligna can be completely
grazed off without harming the plants. The damaged bark exudes copious amounts
of a very acidic gum that seems to show promise for use in pickles and other
acidic foodstuffs (NAS, 1980).
No data observed.
Natal-grown bark contains up to 30.3% tannin compared to 19.1–23.0 at the Cape.
The plant has given negative test for HCN.
Dense, bushy shrub, usually 2–5 m tall; may grow treelike to 8 m tall with a
single main stem (diameter to 30 cm). In spring its usually drooping branches
are clad in beautiful and abundant yellow flowers (NAS, 1980a).
Reported from the Australian Center of Diversity, orange wattle, or cvs
thereof, is reported to tolerate alkalinity, drought, heavy soil, poor soil,
salinity, salt spray, sand, shade, slope, waterlogging, and weeds. (2n = 26)
Acacia saligna is native to the southwestern corner of western
Australia. It was introduced to South Africa in the 1840s in an attempt to
stabilize the shifting sand dunes. It has also been planted in Uruguay, Mexico
Israel, Iran, Iraq, Jordan, Syria, Greece, Cyprus, and North African countries
(NAS, 1980a).
Acacia saligna can grow throughout the tropical and the warm temperate
regions of the world (NAS, 1980a). In its native habitat, the summer
temperature ranges from about 23°–36°C, winter temperatures from
4°–9°C. The plant does not withstand frost and grows best where the
winter and summer means are between 13° and 30°C respectively. Grows
from near sea level to about 300 m, with isolated occurrences at higher
elevations. Particularly drought hardy, it grows where annual rainfall is as
low as 250 mm, though it probably does better with 350–600 mm. It grows well
where annual rainfall is as high as 1,000 mm. Grows mainly on sandy, coastal
plains, but is found from swampy sites and riverbanks to small, rocky hills
(often granitic) and coastal slopes. It occurs on poor acid or calcareous
sands, under the most dry and adverse soil conditions, in moderately heavy
clays and a range of podzols (NAS, 1980a).
Seeds germinate readily; young plants can often be found under mature trees in
the hundreds. Seedlings are easily raised in a nursery and established in the
field. This species develops root suckers and coppices freely. Seeds are
normally treated with boiling water, but nicking the seed coat, soaking in
sulfuric acid, and exposing the seeds to dry heat are also effective (NAS,
1980a).
In Mediterranean countries, the fuelwood from this species is harvested on a
coppice rotation system of 5–10 years (NAS, 1980).
Acacia saligna grows quickly, often reaching up to 8 m tall with a
spread as great as its height in just 4 or 5 years. In very dry situations,
growth rate is slower. Annual yields vary from 1.5 to 10 m3 per ha, depending
on site. Because of its hardiness and profuse reproductive abilities,
Acacia saligna has become a serious menace in parts of South Africa by
invading and displacing indigenous vegetation. It infests water courses
(sometimes decreasing the water available for irrigation), and has proved
difficult to eradicate (NAS, 1980a).
Plantations for fuel have been established in some Mediterranean countries.
But, according to one report from South Africa, the wood is "sappy, light, and
not a popular fuelwood." The plant can withstand some shade and can be grown
as an understory beneath pines or eucalypts in energy plantations or village
fuel and fodder areas (NAS, 1980a). 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.
Acacia saligna supports a diverse and abundant range of herbivores that
cause damage to the plant. Among pests cited are Icerya purchasi
(Hemiptera) and Euproctis fasciata (Lepidoptera) (NAS, 1980a) and
Meloidgogyne sp. (Nematoda)
- N.A.S. 1980a. Firewood crops. Shrub and tree species for energy production.
National Academy of Sciences, Washington, DC.
Complete list of references for Duke, Handbook of Energy Crops
Last update December 20, 1997