Common Name: Black Mangrove

General Information

Bruguiera gymnorhiza is an evergreen tree of the mangrove swamps. Usually growing from 8 - 25 metres tall, though only 10 - 13 metres in India, it can occasionally reach 36 metres[, ]. In many areas it is one of the largest trees of the mangrove swamps, and probably the longest living[]. The straight bole can be 40 - 90cm in diameter, it is buttressed at the base and has many upright knee-roots[].
One of the largest and longest-lived trees in the mangrove forests, it has a wide range of uses and is heavily exploited in the wild, especially for its wood; and for the bark which is used for tannins and dyes[]. The fruits are sometimes sold as a vegetable in local markets[]. The tree is planted in coastal areas and near ponds to provide coastal protection and stabilization of the soil[].
This species is the one of the most widely distributed mangrove species, and is considered common throughout its range. It is threatened by the loss of mangrove habitat throughout its range, however, primarily due to extraction and coastal development, and there has been an estimated 20% decline in mangrove area within this species range since 1980[]. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2011)[].

Known Hazards

None known

Botanical References

Range

Widespread on tropical coasts from E. Africa through Asia to Australia and the Pacific Islands.

Habitat

Characteristic of the landward side of mangroves, usually growing on somewhat dry, well-aerated soil. It often ascends tidal parts of rivers. Sometimes it forms pure stands, but often it is associated with Rhizophora species[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Cultivation Status	Cultivated, Wild

Cultivation Details

A plant of tropical and subtropical, moist to rainforest life zones, where it always grows near the coast at elevations up to 50 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 26°c, but can tolerate 15 - 30°c[]. It can be killed by temperatures of °c or lower[]. It prefers a mean annual rainfall in the range 1,500 - 6,000mm, but tolerates 1,000 - 8,000mm[].
Plants grow best on brackish or saline silts of depositing shores and marshes[]. The tree has proved to be able to grow, flower, fruit and even regenerate in artificial fresh water swamps[]. It can stand any amount of shade[]. Prefers a pH in the range 7 - 8, tolerating 6.5 - 8.5[]. Although it is a mangrove, it is sensitive to high salt concentrations, dying out when concentrations of sodium chloride exceed 3%[].
Black mangrove marks the climax vegetation of littoral forests (mangroves), before the transition to land forest. It is a shade tolerant species that is able to establish itself even in pure stands of Rhizophora species.
It takes 40 years for trees to attain 16cm in bole diameter[].
Plants do not respond well to lopping or coppicing[].
It flowers abundantly in the rainy season[].
Seedlings can remain alive, floating in the water, for 5 - 6 months, which possibly explains the large area of natural distribution[].
Planting is usually not needed because natural regeneration is so successful. Regeneration after felling, however, is usually scant or even absent[]. The natural and artificial regeneration has never been extensively investigated[].

Edible Uses

The leaves and peeled hypocotyls are eaten in times of scarcity in the Moluccas after having been soaked in water to remove the astringent tannins and then boiled[, ].
The starchy central part of the hypocotyl is treated with sugar and then eaten[].

The fruits are sometimes used as an astringent in betel quid when nothing better is available[].

The bark is used as a condiment[].

Medicinal

The bark is used as an astringent medicine against diarrhoea and sometimes malaria[, ]. It is used as an abortifacient[].
The bark is applied externally for treating burns[].

A decoction of the root, combined with the leaves of Piper pyrifolium, is used as a remedy for bleeding, diabetes and hypertension[].

The fruits are suitable as an eye medicine[].

Agroforestry Uses:

This species might be successfully used for reforestation in areas where mangroves have been destroyed[]. It is planted by the coast to provide protection from sea spray, storm surge, and salt-water incursion[].
The tree has been planted in fresh water swamps and also to stabilize dunes[].

Other Uses

The bark is suitable for tanning as it contains up to 35% tanning substance in air-dry bark. It is often mixed with other tannins in the tanning industry[, ]. The tannins can be used to preserve fibres in ropes, sails etc[]. The tannin can be extracted by boiling the bark in large vessels and evaporating down to a solid[].
As in other mangrove species, the percentage of tannin in the bark varies largely from 20% to 43% on dry weight basis, depending on age, season and habitat. The bark of the trunk of large, aged trees is richest in tannin[].

A phlobaphene colouring matter from the bark is sometimes used as a dye for black or dark-brown colour, but this use is considered as minor[].
The bark provides orange to reddish brown dyes without mordanting, and purplish brown, grey and black colours if the fibres or textiles are treated with iron-rich mud or iron salts[].
The skin of the seeds is used to prepare a black dye for traditional skirts in the Pacific[].

The heartwood is red brown; it is distinctly demarcated from the pale brown sapwood. The grain is usually interlocked, texture fine and even. The wood is heavy (about 980 kg/m cubic), strong, hard, moderately durable when exposed to the weather or in contact with the ground[]. It is used for piles, house posts, rafters, fishing stakes, and telegraph poles[, ]. Poles have a life of about 10 years[, ]. The wood can also be used for the paper industry, but the paper is of poor quality[].
The timber is used for fuel and for making charcoal[, ]. It makes a very good fuel and charcoal[, ]. The energy value of the wood is 18,950–20,200 kJ/kg[].

Propagation

Seed germinates whilst still attached to the tree[]. Seedlings can be collected either from the trees or from the ground, they are equally viable[]. They can be planted in a nursery, and transferred to the field 3 - 4 months later[]. Seedlings develop best where the tidal range is only about 0.35 metres and the salinity is 1 - 2.5%[].

Add a Comment:

If you have any useful information about this plant, please leave a comment. Comments have to be approved before they are shown here.

Name:

Email(Private):

Message:

Captcha: How many fingers does the typical human have?