Acacia mearnsii (Bekele-Tesemma, 2007)
| Acacia mearnsii (Bekele-Tesemma, 2007) |
Acacia mearnsii (Racosperma mearnsii) (Fabaceae, Australia)
habit
habit
leaves, flowers, fruits
Common names
- English: Black wattle
- Amargna: Mimosa
Ecology
A small tree native to Australia, where it grows from southern New South Wales to Tasmania. Introduced worldwide and now found both in temperate regions and in cool tropical highlands. In Ethiopia it performs well in Moist and Wet Weyna Dega and Dega agroclimatic zones.
Uses
Firewood, charcoal, poles, posts, medicine, bee forage, ornamental, nitrogen fixation, soil conservation, windbreak, fibre, tannin.
Description
An unarmed shrub or tree, 2–15 m, the trunk providing straight poles in close-planted plantations. Sometimes leans over due to the shallow root system.
- BARK: Smooth, green at first, later black, fissured with resinous gum when cut.
- LEAVES: Compound, feathery dull green, leaf stalk to 12 cm and up to 21 pairs of pinnae, leaflets tiny.
- FLOWERS: Many pale yellow rounded flower heads on a branched stalk, very fragrant.
- FRUIT: Numerous dull brown pods with 3–12 joints, straight or bent. Sections break up and contain the small black seeds.
Propagation
Seedlings, direct sowing at site.
Seed
50,000–85,000 seed per kg; germination 50–80 %.
- Treatment: Immerse seed in hot water, allow to cool and soak for 24 hours before sowing to break dormancy. Burning a thin layer of dry twigs with mature pods spread on an area will usually result in profuse natural regeneration.
- Storage: Seed can be stored for long periods.
Management
Thin if established by direct sowing and the germination was profuse.
Remarks
It is the most widely used tree crop for high-quality tannin. Fast growing but short lived; a tree for woodlots. Potentially a weed on farmland and can be difficult to eradicate. It should not be intercropped as it competes with crops. Crops may also not do well in soils previously planted to black wattle.
