Acacia trachycarpa E. Pritz.

Leguminosae

Common names

Sweet scented miniritchie

Description

Shrub or small tree up to 15 m high, with a more or less viscous, resinose and sticky bark. Spreading crown, up to 10 m in diameter . Dark reddish bark, unbinding in laces that roll upward, typical of some Australian acacias ("minni ritchi" bark in aborigine terminology). Phyllodes flat, narrow to linear, 2-10 cm long x 0.8-3 mm wide, smooth and fragile, with silky hair on the nerves, slightly yellowish on young shoots, central nerve conspicuous, longitudinal lateral nerves obscurely visible, ending, however, with a sharp hardened apex at the top, foliage looking both dense and light from a distance. Flowers golden-yellow grouped in cylindrical or oblong, dense, axillary racemes, clustered by 1-3, 1-2 cm long x 5 mm diameter borne on glabrous or, somewhat resinose 5-25 mm long. Pods yellow-brown, linear, strongly falcate up to forming an open circle, 3-6 cm long x 8-10 mm wide, leathery, resinose and sticky, with a rough, sparsely hairy surface ; seeds obliquely orientated in the pod oblong to circular, somewhat flattened, 5-8 mm x 4-7 mm dark brown to black, with a pale central areola and a pale yellow aril.

Habitat

In the drier parts of its distribution area it becomes riverine growing in dry creeks.

Water

Occurs under 120-400 mm of MAR zones. Drought-tolerance in the coastal Sahel is comparable to that of A. holosericea (Hamel, 1980).

Soil

Appropriate soil reaction is neutral to alkaline.

Distribution

Found North of the Tropic of Capricorn, with warm winters and hot summers. This species was first introduced to Senegel in the early 1970's as Acacia aff. linarioides.

Propagation

Propagation by seeds, ability for coppicing assumed weak.

Products & uses

Used for firewood (4,740 kcal kg^-1 DM) and charcoal, production in the coastal zone of Senegal is satisfactory, but less so in the continental Sahel of Niger, Burkina and N. Cameroon (Cossalter, 1986) ; A. trachycarpa could be used as forage as well, with a density of 1100 shrubs per ha, foliage production was 2 kg phyllodes DM per shrub of a material containing 15 % CP, available year-round, including the dry season when native species have shed their leaves (Hamel, 1980). Pods, however, are not palatable. Other uses are sand binding, secondary windbreaks and urban forestry.

Links for the genus:

• The WattleWeb: Acacias from A-Z
• Seed treatment and inoculation: Instructions for acacias and other NFT (Nitrogen Fixing Trees)
• Sustainable livestock production: Indigenous knowledge in utilization of local trees and shrubs in central Tanzania

References

Maslin 1982 ; Simmons 1981 ; Turnbull 1986 ; Harwood 1993 ; Maslin & McDonald 1996 ; Hamel 1980 (sub A. aff. linarioides) ; Cossalter 1986 ; Cossalter 1987 ; Dommergues et al.1999.