Common Name: Yellow Mangrove

General Information

Yellow mangrove is a glabrous shrub or small tree with a compact crown; it usually grows up to 6 metres tall, but some exceptional specimens in good growing conditions can reach up to 40 metres[]. The bole is usually short and slender, occasionally reaching 40cm in diameter[].
The tree was formerly a commercial source of tannins and dyes. It is still an important local source of these products and is harvested from the wild for them as well as for medicines, timber and fuel.
This species is widespread and common. It is highly utilized and is threatened by habitat loss throughout its range, and there has been an estimated 18% decline in mangrove area within this species range since 1980. However, it is a hardy and prolific species. Mangrove species are more at risk from coastal development and extraction at the extremes of their distribution, and are likely to be contracting in these areas more than in other areas. It is also likely that changes in climate due to global warming will further affect these parts of the range. Although there are overall range declines in many areas, they are not enough to reach any of the threatened category thresholds. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

Range

Coastal areas of the Indian Ocean from Africa to Asia, Australia and the Pacific.

Habitat

Saline creeks and mud flats just above sea-level[]. Typically it occupies sites of the inner mangrove where flooding with salt water is often infrequent and soil salinity may be high due to evaporation[].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Shrub
Height	5.00 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

A plant of tropical and subtropical coastal areas, growing best where temperatures range from 20°c to 26°c and average annual rainfall from 750 mm to 1,500 mm[]. Grows in areas of seasonal rainfall and also in areas where it can rain all year round[].
Usually grows on well-drained soils within the reach of occasional tides[]. Prefers a pH in the range 6 to 8.5[].
The seed germinates while the fruit is still attached to the plant and develops a massive hypocotyl, which contains the food reserve for the seedling. The hypocotyl hangs down from the fruit with the true root at the end. The root has small outgrowths, which are the branch roots all ready to grow out. The plumule too is well-developed, but is enclosed in a sheath holding it in the fruit until the seedling drops from the tree. Seedlings fall like a dart to lodge upright in soft mud into which they penetrate to some depth. They become anchored by the outgrowth of the branch roots and so have a good chance of retaining a hold in the scour of the tide. The seedling is buoyant and if it does not stick in the mud where it drops because of a high tide or for some other reason, it may be transported by water. The seedling becomes established quite quickly. Upward growth carrying the seedling leaves above the level of the flood tide is very rapid and growth may be as much as 60 cm in 24 hours. Later the growth rate declines and seedling development can take a year[].
Flowers open mostly in the evening and remain open the following day, emitting a faint but fragrant odour. Pollination is probably by night-flying insects, although bees also visit the flowers at daytime. Pollen release is explosive and is triggered by delicately touching the petals, which each hold a stamen pair[].
Plants do not respond to coppicing[].

Edible Uses

None known

Medicinal

Numerous applications in traditional medicine have been reported[].

The bark contains tannins and, in general, it is used as an astringent, haemostatic and as a quinine substitute to cure malaria[]. It has also been used to treat diabetes[].
Externally, it is used in lotions to treat malignant ulcers and abdominal ailments[].

Other Uses

The stem bark contains tannins and is used for dyeing and tanning[]. In fishing communities nets and sails are treated with a bark extract to preserve them from decay[]. In South-East Asia, the bark is a major ingredient for the famous 'soga browns' of Javanese batiks[].
For tanning purposes the bark of older trees is preferred because the tannin content increases with age[]. The bark is peeled off and may be used directly, but in India tanning extracts may be prepared from it, and marketed as blocks or powder[].
In central Java the fine 'soga-batik' is still made using vegetable dyes, although on a small scale. The bark of Ceriops tagal, usually called ‘tingi’, is one of the ingredients of the traditional dye-recipes, together with the wood of Maclura cochinchinensis and the bark of Peltophorum pterocarpum. Depending on various proportions of the ingredients, cotton cloth is dyed yellowish to brownish shades in traditional patterns, in a process which often takes several weeks[].
The tannin content of the bark can vary considerably, from 13% to over 40%, which is a common and notable feature of mangrove barks[]. The tannins belong to the group of condensed tannins of the procyanidin type, the reason why dyeing with the bark gives reddish-brown colours[]. The leaves contain less tannin, about 15%, whilst bark from the twigs contains 25 - 41%[].

The heartwood is orange when freshly cut, but turns yellowish brown or sometimes even red on exposure; it is distinctly or indistinctly demarcated from the pale yellow sapwood. The grain is straight, texture very fine. The wood is heavy with an average density of 960 kg/m3 at 15% moisture content. It is moderately durable but in contact with the ground it decays in about 2 years. The timber is not resistant to marine borers. Seasoned wood is comparatively resistant to splitting on shock and it is thus suitable for tool handles[]. In Africa Ceriops tagal provides poles and planks for house building, small planks for boat building including paddles and oars, and fishing stakes[]. For house building it is preferred by many communities (e.g. the Giriama people in Kenya) because it grows long and straight and is suitable for making wattlework for walls and roofs[]. The wood has been used as a source of pulp. An extract of the bark is used as a binder for particle board[].
Communities living along the East African coast and islands use the wood as a medium-quality commercial firewood. In some cases it is converted to a high quality charcoal, mainly from mangrove forests close to urban centres[, ]. This species is highly prized for fuelwood in many parts of its range, where it is considered second only to Rhizophora species in the mangrove swamps[]. In some areas it is said to burn with too hot a flame for domestic use, causing damage to cooking pots[].

Propagation

Seed - commences germination whilst still on the tree and is best harvested at this stage and planted out into its permanent site. The seedlings are small and delicate and should be collected and transported to the planting areas with care[]. Seedlings do not tolerate excessive desiccation, but they establish quickly[].

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