Agroforestree Database

Local names:
 Amharic (lebbek), Arabic (lebbek,labakh,daqn el-Basha,dign el basha,laebach), Bengali (sirisha,sirish), Burmese (kokko), Creole (tcha tcha), English (english woman's tongue,siris tree,woman’s tongue tree,East Indian walnut,acacia amarilla,fry wood,lebbec

Albizia lebbeck can attain a height of 30 m and a diameter of 1 m; more often it is 15-20 m tall with a diameter of 50 cm; bark grey-violet with rusty brown breathing pores, rough and fissured.

Compound leaves bipinnate, glabrous or slightly hairy on the axis; pinnae in 2-4 pairs, each with 2-11 pairs of obliquely oblong leaflets 15-45 x 8-22 mm, shortly stalked; glabrous glands are raised, elliptic to circular, on the upper side of the stalk close to the base and between most pairs of leaflets. 

Flowers appear shortly after new leaves, are white, heavily scented, with the stamens free above the corolla, in heads 18-36 mm across excluding the stamens, on a stout stalk 5-7.5 cm long, appearing singly or in small clusters in the leaf axils and in terminal panicles; stamens 30-40, yellowish-green on top side, white underside, up to 5 cm long; flower-stalks up to 5 mm long; corolla tube, 1 cm long.

Pods pale straw to light brown at maturity, narrow-oblong, 15-26 x 3-5 cm, papery, leathery, flat and not raised or constricted between seeds; seeds brown, flat, orbicular or elliptic, 8-10 x 6-7 mm; transversely placed with 6-12 in each pod. 

The genus is named after Filippo del Albizzi, a Florentine nobleman who in 1749 introduced A. julibrissin into cultivation. The species name is from the Arabic name for this plant, ‘laebach’. When agitated by the wind, the pods and enclosed seeds are said to produce an incessant rattle likened to women’s chatter, hence the name ‘woman’s tongue’.

Ecology

A. lebbeck is a dominant species in semi-evergreen vine forests (monsoon forest) in areas with a mean annual rainfall of 1300-1500 mm and a very dry winter. It is also found in semi-deciduous microphyll vine thicket on screes of quartz sandstone mountains. It can withstand long, hot, dry periods and cold winters. The species occurs on soils overlying basalt and among sandstone boulders and basalt outcrops on breakaway slopes. It is also found on the banks of riverine sites, on stabilized dunes or low lateritic ledges above the beach. After the 1st year, it can tolerate droughts and some frost.

Native range
Australia, Bangladesh, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Thailand

Tree management

A. lebbeck coppices well, responds to pollarding, pruning and lopping, and will produce root suckers if the roots are exposed. Typical spacing is 3 x 3 m for fuelwood, and 5 x 5 m for timber. Fuelwood plantations spaced at 3 x 3 m clear felled on a 10-year rotation produce about 50 cubic m/ha of stacked fuelwood. In Queensland A. lebbek reaches about 11 m in height and 50 cm dbh in 30 years. The trees are vulnerable to strong winds and are killed by even light fires.

Seed storage behaviour is orthodox. Viability is maintained for several years in hermetic storage at room temperature with 11-15% mc; even seeds stored 30 years show 5% viability. However, the seed is liable to bruchid attack, which may occur while the pods are still on the tree, so a little contact insecticide should be mixed with the stored seed. There are about 5000-12 000 seeds/kg.

A. lebbeck is a dominant species in semi-evergreen vine forests (monsoon forest) in areas with a mean annual rainfall of 1300-1500 mm and a very dry winter. It is also found in semi-deciduous microphyll vine thicket on screes of quartz sandstone mountains. It can withstand long, hot, dry periods and cold winters. The species occurs on soils overlying basalt and among sandstone boulders and basalt outcrops on breakaway slopes. It is also found on the banks of riverine sites, on stabilized dunes or low lateritic ledges above the beach. After the 1st year, it can tolerate droughts and some frost.

It is best established using potted seedlings, although bare-rooted seedlings, direct seeding and stump cuttings have all been used successfully. Seed pretreatment involves scarification and immersion in boiling hot water then cooling and soaking for 24 hours, or acid treatment to break seed-coat dormancy. Germination improves after storage for 2-4 years, but satisfactory germination (50-60%) has been obtained from fresh seeds. Freshly collected seed has about 70% germination capacity after 1-2 months.
About 880 pods weigh 1 kg and will yield about 300 g of seed.

Erosion control:  Due to its extensive, fairly shallow root system, A. lebbek is a good soil binder and is recommended for eroded lands and erosion control, for example along river embankments.

A. lebbeck is grown in some areas primarily as fodder for camels, water buffalo and cattle. The leaves are reported to be good fodder, with 17-26% crude protein; 100 kg of leaves yield 11-12 kg of digestible protein, and 37 kg of digestible carbohydrates. The pods contain saponin and are not eaten in large amounts by sheep, although cattle eat them readily.

Apiculture:  Its whitish flowers are fragrant, attracting bees. Highly regarded by bee-keepers for the light-coloured honey its nectar provides.

An excellent fuelwod species with a calorific value of 5200 kcal/g. A. amara fruits can yield 10 barrels of ethanol per hectare.

Timber:  Sapwood is pale; heartwood is dark brown with black streaks and very decorative. It is moderately heavy and hard, strong and fairly durable, with a specific gravity of 0.5-0.6 kg/cubic m. The wood seasons well, works and polishes easily, can be used for interior moulding, parquet, furniture, panelling, turnery and general construction. It is also used for making agricultural implements and mine props. Timber plantations in India clear felled after 25-30 years yield about 10-12 cubic m/ha per year of timber, but under semi-arid conditions and on shallow soils, a mean increment of 2-3 cubic m/ha is obtained.

Shade or shelter:  The species is commonly grown as a shade tree in pastures, tea, coffee and cardamom plantations, and along avenues. It can be planted in exposed coastal situations and as quick-growing shelter for less hardy plants.

Tannin or dyestuff:  The bark is used locally in India for tanning fishing nets (tannin content of 7-11%).

Medicine:  Leaves and seeds are used for eye problems, and the bark to treat boils. Saponin from pods and roots has spermicidal activity.

Gum or resin:  The trunk yields a reddish gum that is used as an adulterant of gum arabic.

Nitrogen fixing:  A. lebbeck is not Rhizobium specific, and native strains are nearly always capable of producing an abundance of nodules.

Ornamental:  In India A. lebbeck is often planted along roads and in homegardens.

Soil improver:  The nitrogen-rich leaves are valuable as mulch and green manure.